study companion unit 1 biology 108 (spring Benevidis)
In aqueous solution at 25 °C, the product of the H+ and OH- concentrations is constant at?
- 10^-14 [H+][OH-]= 10^-14
What are the two functional groups found in all amino acids?
1. Amino 2. Carboxyl
What are the classes of the large molecules that all living things fall into?
1. Carbohydrates 2. proteins 3. nucleic acids 5. lipids
List the two types of nucleic acids and explain how they differ from one another
1. DNA - two strands/ the blueprint of biological guidelines that a living organism must follow to exist and remain functional. Medium of long-term, stable storage and transmission of genetic information 2. RNA - one strand/ helps carry out DNA's blueprint guidelines. Transfers genetic code needed for the creation of proteins from the nucleus to the ribosome
Describe some of the distinguishing features of eukaryotes:
1. Have DNA in a nucleus that is bounded by a membranous nuclear envelope 2. Have membrane-bound organelles 3. Are generally much larger than prokaryotic cells How much bigger are
Describe some of the distinguishing features of prokaryotic cells:
1. Lack a nucleus 2. Have their DNA in an unbound region called the nucleic 3. Lack membrane-bound organelles
What are the three components from which a nucleotide is constructed?
1. a ring-shaped molecule belonging to the class of purine or pyrimidine bases 2. a 5-carbon, or pentose, sugar (deoxyribose) 3. one or more phosphate groups
what are the tree major components of cilia and flagella?
1. core of microtubule sheated by plasma membrane 2. basal body that anchors cilium or flagellum 3. motor protien called dynein which drives bending movements of a cilium of fugellum
What establishes the membrane potential?
1. electrogenic pump - transport proteins that generate voltage across a membrane 2. sodium-potassium pump - major electrogenic pump of animal cells 3. proton pump - main electrogenic pump of plants, fungi, and bacteria
The pH of the Great Salt Lake is ~10, while the pH of sea water is ~8. From this information, The Great Salt Lake is __ times more ___ than sea water.
100 .... Basic
Acid precipitation has lowered the pH of a particular lake to 4.0. What is the hydrogen ion concentration of the lake?
10^-4 M
In a solution with a pH value of 4, the H+ ion concentration is __.
10^-4 M
How rapidly do adjacent phospholipids "switch" positions?
10^7 times per second; can travel the length of many bacterial cells in 1 second
In this figure of an integral membrane protein, which of the following groups of terms correctly describes the three labeled regions (1,2,3) of the protein?
1=hydrophilic; 2=hydrophobic; 3=hydrophilic
For every one unit change in the pH of a solution how much does the concentration of H+ change?
1pH unit therefore represents a 10-fold increase or decrease in hydrogen ion concentration
Electrochemical Gradient
2 combined forces of a chemical force (concentration gradient) and electrical force (effect of membrane potential on ion movement) that drive the diffusion of ions across a membrane
How many carbon atoms are in this structure of pyruvate, an important molecule in glucose metabolism?
3 (picture)
How many carbon and hydrogen atoms are I the molecule shown here?
3 carbon atoms and 7 hydrogen atoms
Uracil is one of the bases found in nucleic acids. the structure is shown. this molecule has __ carbon atoms.
4
This is the structural formula for glyceraldehyde, an intermediate in carbohydrate metabolism. How many hydrogen atoms are in this molecule?
6
Consider the molecule represented in the figure shown. There are ____ carbon atoms and ____ hydrogen atoms in this molecule.
6 ... 12
The figure at right shows the effect of pH on the activity of the enzymes pepsin, amylase, and arginase. Each enzyme has different substrates. Solution 1 has equal amounts of all three substrates for the tree enzymes. Solution 2 has equal amounts of all three enzymes. The most direct way to convert solution 1 to contain only pepsin substrate (removing the substrates for amylase and arginase) is to adjust the pH of solution 1 to ___ and add the enzymes from solution 2.
8
how many carbon atoms are in this molecule of caffeine?
8
Creatine is a molecule often used in muscle cells to store energy, the structure is shown here. This molecule has __ hydrogen atoms.
9
Consider the molecule shown in this figure. There are __ carbon atoms and __ hydrogen atoms in this molecule.
9 ... 11
What is the function of the nuclear lamina. Which type of cytoskeletal component is it constructed from?
A netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus. lines the nuclear side of the envelope
Which of the following descriptions best fits the class of molecules known as nucleotides?
A nitrogenous base, a phosphate group, and a pentose sugar
Which of the following statements about the differences between a nucleolus and nucleoid is true?
A nucleoid is found in prokaryotic cells and is a non-membrane bound region of DNA, a nucleolus is found in a nucleus in eukaryotic cells and is a region containing a high density of rRNA
Which of the following statements about a nucleus and a nucleoid is true?
A nucleus is found in plant and animal cells, a nucleoid is found in bacteria cells.
define single bond
A pair of shared electrons
A sample of cells was analyzed and found to contain a nucleus, a central vacuole, and a cell wall. These cells are most likely from __.
A plant
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma, membrane, and mitochondria. It could be a cell from __.
A plant or an animal
define cation
A positively charged ion
Which of the following is possible due to the high surface tension of water?
A water strider (a bug) can walk across the surface of a small pond.
Which of the following polysaccharides would be found in plants, but not animals?
Amylose, starch, amylopectin, cellulose are all found predominantly in plants, not animals.
Which of the following increases membrane fluidity at cool temperatures?
An abundance of unsaturated acyl chains in the membrane lipids. High cholesterol levels.
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that __.
An electron may move to an electron shell farther out from the nucleus
All of the following are part of a prokaryotic cell except __.
An endoplasmic reticulum
The interaction between a K+ and a Cl- is __ bond wile the interaction between water molecule (H2O) and an ammonia molecule (NH3) is __ bond.
An ionic ... a noncovalent
The amino acids lysine and aspartic acid are both ionized at physiological pH. Lysine has an ionized amino group in the side chain, and aspartic acid has an ionized carboxyl group in the side chain. If these two ionized groups are located close together in space, what type of interaction is possible between these side chains?
An ionic bond.
What is the Golgi apparatus function?
An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the endoplasmic reticulum.
Which of the following statements is false in describing the behavior of water transport in animal and plant cells?
Animal cells will undergo plasmolysis in hypertonic solutions
Which of the following statements is false in describing differences between plant and animal cells?
Animal cells, but not plant cells, contain mitochondria.
What is the major electrogenic pump of animals? Plants?
Animals - sodium potassium pump Plants - proton pump
define matter
Anything that has mass and takes up space
Thalidomide is a drag prescribed in the US in the late 1950s as a treatment for morning sickness during pregnancy. It was determined that the drug was present in two enantiomeric forms, one form was effective, while the other form caused birth defects. When a molecule can be present as enantiomers that means they __.
Are mirror images of each other
What is evaporative cooling?
As liquid evaporates, the liquid left behind is cooler because the warmer liquid is turning into a gas.
Which of the following conditions would increase membrane fluidity?
At cool temperatures, the presence of cholesterol in the membrane bilayer. An increase in unsaturated tails of the phospholipids in the membrane bilayer.
What is an isotope?
Atoms of the same element that have different numbers of neutrons
define atom
Basic unit of matter
Hydrangeas are plants that produce spectacular blossoms of differing color, depending on the pH of the soil. If a blue flower is desired, the soil needs to be acidic. Therefore, the pH level of the soil should be adjusted to __.
Below 5.5
The cytoskeleton has three major components. In order of increasing size, they are ___.
Microtubules, intermediate filaments, microfilaments
In which organelle would you find an outer membrane, cristae, free ribosomes, and circular DNA?
Mitochondria
The Golgi apparatus is involved in__.
Modifying, packaging, and transporting proteins that are to be released from the cell
define amino acid
Monomer (building blocks) for making proteins, held together by peptide bonds
dehydration reaction
Monomers connected by reaction in which 2 molecules are covalently bonded to each other w/ loss of water molecule -when 2 monomers bond each contribute part of water molecule, released during reaction - one provides hydroxyl group (-OH) other hydrogen(-H) -action repeated as monomers added to chain, 1 by 1 making polymer
Glycosidic bonds link __ monomers, while peptide bonds link __.
Monosaccharide .... amino acids
define passive transport
Movement across cell membrane--high to low--does NOT require energy
define bulk transport
Movement of substances, usually large particles, across the plasma membrane using vesicles. 91
The major factor limiting cell size is the __.
Need for energy
Which of the following atoms have a valence number of 5?
Nitrogen
What is the change in free energy at chemical equilibrium?
No net change
The enamel on teeth is resistant to most substances except acids. In regard to enamel on teeth, which of the following beverages should be avoided?
Both Cola (pH 3.3) and beer (pH 4.5)
Which of the following statements is false in describing the similarities and differences in nucleic acids?
Both DNA and RNA are usually observed as two strands which form a double helix.
Which of the following is a polymer?
Both DNA and starch
Which of the following transport processes is passive, not requiring energy?
Both diffusion and facilitated diffusion
Which of the following atoms has an electronegativity value most dissimilar to hydrogen and will form a polar covalent bond with hydrogen?
Both nitrogen and oxygen
Which is the correct association with the two organelles most directly involved in energy metabolism in eukaryotic cells?
Cellular respiration/ATP synthesis in the mitochondria; photosynthesis in the chloroplast
Which of the following polymers is not a polysaccharide?
Cellulose, amylopectin, starch, glycogen
Cranberry juice has a pH of ~2. Orange juice has a pH of ~4. Which of the following statements is true?
Cranberry juice is 100 times more acidic then orange juice.
Which of the following is not a component of a nucleus?
Cristae
The main nucleic acids in cells are __.
DNA and RNA
DNA and RNA are both nucleic acids. Which of the following is a correct description of differences between these two polymers?
DNA is composed of A, G, C, T nitrogenous bases, RNA is composed of A, G, C, U nitrogenous bases.
The presence of cholesterol in the plasma membranes of some animals __.
Enables the membrane to stay fluid more easily when cell temperature drops.
A chemical reaction that has a positive delta G is correctly described as ___.
Endergonic
What organelle is shown to the right?
Endoplasmic reticulum
The pancreas is an organ found in many animal species. It synthesizes and secretes a large quantity of protein hormones (insulin is an example). You would expect a pancreas cell to have a large quantity of __.
Endoplasmic reticulum and Golgi apparatus
The pancreas is an organ found in many animals. It synthesizes and secretes a large quantity of protein hormones. You would expect a pancreas cell to have a large quantity of __.
Endoplasmic reticulum and Golgi apparatus
Which statement about thermodynamics is false?
Entropy tends to move towards a minimum.
The arrangement of lipid bilayers and other components in a membrane is the basis for the currently widely accepted description which is called the __.
Fluid mosaic model
Name the differences between free ribosomes and bound ribosomes?
Free ribosomes are suspended in the cytosol and mainly function in the cytosol. Bound ribosomes are bound to ER or the nuclear envelope. Bound ribosomes generally make protein for insertion into membranes, for secretion, or packaging into organelles.
If a molecules movement across a membrane is said to move down its concentration gradient. This means the molecule moves ___.
From high concentration of the molecule to low concentration of the molecule
Which of the following is not a polymer?
Glucose
Starch is a polymer of __ and is often found in ___, while glycogen is a similar polymer, but found predominantly in__.
Glucose ... plants.... Animals
Starch is a polymer of ___ and is classified as a __.
Glucose .... Carbohydrate
Glucose (a monosaccharide) enters most cells by facilitated diffusion. This being the case, which of the following statements is true?
Glucose is a polar molecule and cannot diffuse across the hydrophobic core of a membrane without the aid of a transporter protein. Glucose is transported into the cell when there is a higher glucose concentration outside the cell then inside the cell.
Starch is a polymer composed of __ monomers, hemoglobin (a protein) is a polymer composed of __ monomers, and DNA is a polymer composed of __ monomers.
Glucose... amino acid .... Nucleotide
Starch is a polymer composed of __ monomers, hemoglobin (a protein) is a polymer composed of __ monomers, and DNA is a polymer composed of __ monomers.
Glucose... amino acid... nucleotide
Starch is a polymer of ___ and is often found in ___, while glycogen is a similar polymer, but found predominantly in___.
Glucose.... Plants..... animals
A triacyglyceride is composed of a ___.
Glycerol backbone with three fatty acids
The simple sugars of carbohydrate polymers are linked by __ bonds, while the amino acids of proteins are linked by __ bonds.
Glycosidic .... Peptide
Covalent bonds linking monomers in saccharides are called __ bonds and covalent bonds linking monomers in proteins are called ___ bonds.
Glycosidic.... peptide
Covalent bonds linking monomers is saccharides are called ___ bonds and covalent bonds linking monomers in proteins are called __ bonds.
Glyosidic ... peptide
Some integral membrane proteins are modified by having carbohydrates attached to the part of the protein that is not embedded in the lipid bilayer. This modification occurs in the __, and is ultimately found on the ___ face(s) of a plasma membrane.
Golgi apparatus .... External
What organelle is depicted here? What is its function in a cell?
Golgi apparatus.... Processing of secretory vesicles
Which of the following examples is of a noncovalent bond?
H ***O
Which of the following examples is of a noncovalent bond?
H-O
Polar molecules __.
Have an unequal distribution of electric charge
Polar molecules ___.
Have an unequal distribution of electric charge
Amphipathic molecules __.
Have hydrophilic and hydrophobic region and include phospholipids and integral membrane proteins
Amphipathic molecules __.
Have hydrophilic and hydrophobic regions; include phospholipids and integral membrane proteins
When you drop an ice cube into a cup of Pepsi, which of the following is true?
Heat flows from the Pepsi to the ice cube
The cooling affect of seat or perspiration is due to ___.
High heat of vaporization
The cooling affect of sweat of perspiration in humans is due to what property of water?
High heat of vaporization
The cooling affect of sweat or perspiration in humans is due to what property of water?
High heat of vaporization
Ocean temperatures and coastal land areas have more stable temperatures than inland area because large bodies of water can absorb a large amount of heat from the sun in the daytime yet only warm a few degrees. What property of water explains this phenomenon?
High specific heat
Ocean temperatures and coastal land areas have more stable temperatures than inland areas because large bodies of water can absorb a large amount of heat from the sun in the daytime yet only warm a few degrees. What property of water explains this phenomenon?
High specific heat
Ocean temperatures and coastal land areas have more stable temperatures that inland areas because large bodies of water can absorb a large amount of heat from the sun yet only warm a few degrees. What property a water explains this phenomenon?
High specific heat
The climate modifying property of lakes and oceans is due to waters __.
High specific heat
When a glucose molecule is metabolized to release energy, ~40% of the energy is converted into usable energy while ~60% is lost as heat. What property of water acts to keep temperature levels in the cell from rising to dangerous levels?
High specific heat
When sugars and fats are metabolized to release energy for an organism, ~38% of the energy is converted into useable energy while 62% is lost as heat. What property of water acts to keep temperature levels I the cell from raising too dangerous levels?
High specific heat
Mitochondria and chloroplasts have extensive membrane structures to increase membranous surface area for membrane-bound proteins. Mitochondria accomplish this by ___ while chloroplasts have __.
Highly folded cristae ..... internal membranous thylakoids
Which of the following solutions has the greatest concentration of hydroxide ions?
Household ammonia at pH 11.5
The interaction between a water molecule and an ammonia molecule is a __ bond while the interaction between Na+ and Cl- is a(n) __ bond.
Hydrogen ... ionic
Hydronium ion (H30)
Hydrogen atom in a hydrogen bond between 2 water molecules can shift from one water molecule to other
What type of bond/interaction best describes the attraction of water molecules to one another?
Hydrogen bond
Which is not involved in the tertiary structure of a protein?
Hydrogen bonding between backbone atoms.
The high specific heat and cohesive forces characteristic of water are a result of __.
Hydrogen bonding between water molecules
Why does ice float in liquid water?
Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water.
Larger molecules are cleaved into smaller units by __ reactions requiring the addition of water.
Hydrolysis
Phospholipid bilayers are often drawn as shown to the right. The round circles represent __ and the zig-zag lines represent __.
Hydrophilic head groups .... Hydrophobic acyl chains
Phospholipid bilayers are often drawn as shown to the right. The round circles ___ represent ___ and the zig-zag lines represent __.
Hydrophilic head groups ..... hydrophobic acyl chains
Phospholipid bilayers are often drawn as shown to the right. The round circles represent __ and the zig-zag lines represent __.
Hydrophilic head groups ..... hydrophobic acyl chains
In an integral membrane protein, one would typically find __ regions in the interior of the membrane and __ regions on the exterior of the membrane. This type of molecule is called __.
Hydrophobic ... hydrophilic ... amphipathic
What are the 7 functional groups?
Hydroxyl Carbonyl (ketone, aldehyde) Carboxyl Amino Group Sulfhydryl Phosphate Methyl
Which functional group below is not present in this structure?
Hydroxyl group
Which of the following functional groups is structurally most similar to the sulfhydryl group?
Hydroxyl group
Plant cells are healthiest when in ___ solutions and animals' cells are healthiest when in __ solutions.
Hypotonic .... Isotonic
The preferred environment for a plant cell is __, which animal cells do the best in__ solution.
Hypotonic .... Isotonic
Which of these sugars is an aldohexose?
Image B and C both images have a double bond O at the end of hexane chain. Each carbon down the chain has H or OH on one side or the other.
A nucleus is___.
None of the above
Which of the following statements concerning enzymes is false?
None of the above, all of the statements are true
Which of the following statements about starch and cellulose is false?
None of the above, all the statements are true.
Which of the following statements about the carboxyl group is not true?
None of the above, all the statements are true.
Which of the following is not an example of a glyosidic bond?
None of the above, they are all glyosidic bonds.
How does a bacterial cell (prokaryote) still function properly without membrane bound organelles?
It is highly folded, which provides more surface area to be able to carry out the functions that organelles usually do in eukaryotes
What does the endomembrane system do?
It regulates protein traffic and performs metabolic functions in the cell
The maximum size of a cell is limited by __.
Its need for enough surface area to make exchanges with its environment
The requirements of carrying out cellular metabolism does what to cells?
Limits the size of cells
When limp celery stalks are placed in a bowl of tap water, the stalks become firm within hours. Which statement best describes why this happens.
Limp celery cells are hypertonic to tap water and water enters the cells.
Which geometric arrangement is formed between two C atoms when they form a double bond?
Linear
In the fluid mosaic model of cellular membrane structure, 'fluid' describes the __ component and 'mosaic' describes the __ component.
Lipid .... Protein
Define polymer
Long molecules made up of many similar building blocks (monomers)
Each winter Lake Erie freezes. Diehard fisherman can cut holes in the ice and catch fish that are still alive under the frozen ice. What property of water explains these activities?
Low density in it's solid form
In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components. Which of the following organelles functions in this compartmentalization?
Lysosome
Which of the following pairs is mismatched?
Lysosome protein synthesis
Which organelles compartmentalizes degradative enzymes to prevent autodigestion of the cell?
Lysosomes
define nucleolus
Makes ribosomes
Describe the endomembrane system
Many different membranes of the eukaryotic cell which include the nuclear envelope, the ER, Golgi apparatus, lysosomes and various vesicles and vacuoles.
The protein and carbohydrate composition on the interior and exterior sides of a plasma membrane are asymmetric. One reason for this is that __.
Membrane proteins modified inside of the Golgi end up on the outside of plasma membranes
Example of a hydrocarbon
Methane (CH4)/ocatane
The cytoskeleton is composed of three different filament types. Which of the following is the correct order of these filaments from smallest to largest diameter?
Microfilaments, intermediate filaments, microtubules
In prokaryotic cells DNA is found in the ___ and in eukaryotic cells most DNA is found in the ___.
Nucleoid .... Nucleus
Four of the five answers listed below are familiar organelles in the cytoplasm. Select the exception.
Nucleolus
A phosphodiester bond links __ monomers, which ester bonds link __.
Nucleotide .... Glycerol to fatty acids
___ are the subunits of nucleic acids and ___ are the subunits of proteins.
Nucleotides .... Amino acids
___ in nucleic acids are connected by ___ bonds.
Nucleotides ..... phosphodiester
DNA in eukaryotic organisms is found primarily in the __.
Nucleus
What is the mass number?
Number of protons and neutrons
hydroxly
OH-, polar, attracts water molecules and helps dissolve organic compounds like sugar. (example ethanol)
A covalent bond is likely to be polar when __.
One of the atoms sharing electrons is more electronegative than the other atom
A covalent bond is likely to be significantly polar when __.
One of the atoms sharing electrons is more electronegative than the other atom
In a research article printed in Medicine and Biology, 2006, "The Electron-microscopic findings on the liver in chronic abuse of heroin" the authors found that the most prominent changes in cellular organelles was the enlargement and increase number of smooth endoplasmic reticulum. Which of the following statements most likely explains this observation?
One of the functions of the smooth ER is detoxification.
define osmoregulation
Osmoregulation is the control of the water balance of the blood, tissue or cytoplasm of a living organism
If a plant cell is put in an environment which is hypertonic to the cytoplasm, what will the net movement of water be?
Out of the cell, leading to plasmolysis.
The Golgi apparatus ___.
Packages and modifies proteins
Facilitated diffusion is a form of __.
Passive transport that allows solute molecules to diffuse through by means of carrier proteins
What is the correct match between the type of linkage and the monomer?
Peptide bonds link amino acids; ester bonds link fatty acids with glycerol; phosphodiester bonds link nucleotides
Which organelle is primarily involved in degrading hydrogen peroxide (H2O2)?
Peroxisomes
The molecule shown is an amino acid, cysteine. Which functional group listed below is not present in this molecule?
Phosphate
Covalent bonds linking monomers in DNA are __ bonds and covalent bonds linking fatty acids to a glycerol backbone in lipids are __ bonds.
Phosphodiester ... ester
Covalent bonds linking monomers in DNA are called ___ bonds and covalent bonds linking fatty acids to a glycerol backbone in lipids are called __ bonds.
Phosphodiester ... ester
Covalent bonds linking monomers in DNA are __ bonds and covalent bonds linking fatty acids to a glycerol backbone in lipids are __ bonds.
Phosphodiester .... Ester
Monomers in DNA are covalently linked by ___ bonds, while monomers in proteins are covalently linked by __ bonds.
Phosphodiester ..... peptide
Which of the following macromolecules is not a polymer?
Phospholipids
Which of the following types of molecules are the major structural components of the cell membrane?
Phospholipids and proteins
Differences between plant cells and animal cells include all of the following except __.
Plant cells do not contain mitochondria
Define plasmolysis
Plant cells exposed to low water potention. water moves out causing it to shrink
A cell has the following molecules and structures: DNA, plasma membrane, proteins, and Golgi apparatus. This could be a __ cell.
Plant or animal cell
Protein structure is the most complex and diverse of all the macromolecules. Which protein structure level is defined by hydrogen bonds between main chain (or backbone) atoms?
Second structure
The figure to the right best illustrates the ___.
Secondary structure of a polypeptide
The primary structure of a protein is determined by its __.
Sequence of amino acids
Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
The double bonds form a kink in the fatty acid tail, forcing adjacent lipids to be further apart.
why is it called a system
The endomembrane system (endo = "within") is a group of membranes and organelles
Potential energy is __.
The energy that mater possesses because of its location or structure
Which cellular component of eukaryotic cells is most involved in sensing the environment outside the cell?
The extracellular matrix
Differences in cell structure between plant and animal cell result in different effects of osmosis. Which of the following statements is true?
The plant cell wall prevents cell lysis when in hypotonic solutions.
define autophagy
The process of self-digestion by a cell through the action of enzymes originating within the same cell
Which of the following is not a known function of the cytoskeleton?
To maintain a critical limit on cell size
Why do phospholipids form a bilayer structure in an aqueous environment?
To orient the hydrophilic head groups at the surfaces near water and to sequester the hydrophobic acyl chains in the core away from water.
What is a transport protein? A channel protein? A carrier protein?
Transport proteins - allow passage of hydrophilic substances across the membrane Channel proteins- have a hydrophilic channel that certain molecules or ions can use as a tunnel Carrier proteins- transport proteins that bind to molecules and change shape to shuttle them across the membrane. A transport protein is specific for the substance it moves
A glycerol molecule with ester bonds to three fatty acids in called a __.
Triacylglycerol
What are isomers?
Two or more compounds having the SAME MOLECULAR FORMULA but different structural formula and properties.
Define polysaccharide
a carbohydrate (e.g., starch, cellulose, or glycogen) whose molecules consist of a number of sugar molecules bonded together.
what is a hydrocarbon?
a compound made of hydrogen and carbon atoms
What is a glycosidic linkage (bond)?
a disaccharide is formed when a dehydration reaction joins two monosaccharides; covalent bond
What does a good scientific model do in addition to explaining current observations and experimental results?
a good model makes predictions and shapes future research; they inspire experiments, and models survive theses tests without modification; new findings may make it obsolete, but it may not be scrapped, but revised to incorporate new observations
define chlorophyll
a green pigment, present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis
define temperature
a measure of the average kinetic energy of the particles in a substance
define monomer
a molecule that can be bonded to other identical molecules to form a polymer.
what determines the shape of a molecule?
a molecules shape is determined by the positions of its atoms valence orbitals
what is the difference between a nonpolar and polar covalent bond?
a nonpolar covalent bond, the atoms share electrons equally. In a polar covalent bond, one atom is more electronegative and the atoms dont share the electrons equally
Which statement about membrane phospholipids is not true?
They flop readily from one side of the membrane to the other.
Which of the following is true of geometric isomers?
They have variations in arrangement around a double bond.
what is an electron shell?
an electron's state of potential energy
What is an element? How does it differ from a compound?
an element cant be broken down by chemical means. compound is joined by chemical bonds.
define trace element
an element that is essential for life but required in extremely minute amounts
What is chitin? How does its structure differ from glucose?
another structural polysaccharide, found in the exoskeleton of arthropods; provides structural support for cell walls of fungi it has different chemical groups coming off the sugar molecules
what is and acid?
any compound that forms H+ ions in solution
The two strands making up the DNA molecule
are held together by hydrogen bonds and van der Waals forces.
Dynamic Equilibrium
as many molecules cross in one direction as in the other
what is the relationship between bonding capacity and the number of unpaired electrons in an atoms valence shell?
bonding capacity(valence) usually equals the number of unpaired electrons in the valence shell
Which of the following organelles fits this description? - it is involved in energy metabolism -it possesses an inner and outer membrane - it has characteristics resembling prokaryotic cells - it contains DNA that is replicated along with the organelle.
both mitochondria and chloroplasts
What is the difference between a cis and trans fat?
cis: same side double bond that cause it to bend trans: opposite side double bond
The pH scale shown indicates pH values of several common solutions. Which substance is ~100 times more acidic than pure water at neutral pH?
coffee
List the four emergent properties of water that contribute to Earth's fitness for life
cohesion behavior, ability to moderate temperature, expansion upon freezing, versatility as solvent
Which of the emergent properties are dependent upon water's ability to form hydrogen bonds?
cohesive behavior, ability to moderate temperature, expansion upon freezing.
define nuclear pore
complex opening in a nuclear membrane
what protein subunits are microfilaments constructed from?
composed of actin
The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA
contains less oxygen
describe versatility as solvent
a solution is a liquid that is a homogeneous mixture of two or more substances. then dissolving agent of a solution is the solvent. the solute is the substance that is dissolved. the water is versatile solvent due to its polarity. an aqueous solution is one in which water it the solvent.
Define Alpha Glucose:
a specific isomer of glucose, with a difference of group 1 with -OH in the group point of carbon 1
Define Beta Glucose:
a specific isomer of glucose, with a difference of group 1 with an -H int he group point of carbon 1
what is a base
a substance that reduces the hydrogen ion concentration of a solution
Define electrogenic pump
a transport protein that generates voltage across a membrane
What is an enzyme?
a type of protein that acts as a catalyst speeding up chemical reactions; can form their functions repeatedly as workhouses that carry out the processes of life
What is a hydrogen bond?
a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other.
Define electronegativity
ability of an atom to attract electrons
Water's high specific heat is manly a consequence of the
absorption and release of heat when hydrogen bonds break and form.
The movement of a substance across a biological membrane against its concentration gradient with the help of energy input is
active transport.
aminos
acts as a base and can pick up a proton from the surrounding solutions
What is a hydrolysis reaction?
adds a water molecule and breaks a bond
what is a hydrolysis reaction?
adds a water molecule and breaks a bond
Selective Permeable Membrane
allows some substances to cross the membrane while restricting or excluding others
What environmental factors can affect a protein's conformation?
alterations in pH, salt concentration, temperature...etc.
If the process of diffusion is random, why may a population of molecules exhibit a net movement in one direction?
although each molecule moves randomly, diffusion of a population of molecules may exhibit a net movement in one direction as molecules diffuse down their concentration gradient
Which type of molecules are able to pass freely through a membrane? Which type are hindered?
hydrophobic (nonpolar)molecules, such as hydrocarbons, CO2, and O2 can dissolve in the lipid bilayer and pass through the membrane rapidly ions, and polar (hydrophilic) molecules, such as sugars, do not cross the membrane easily
Identify the functional groups in the molecule shown at the right.
hydroxyl and carbonyl (ketone)
A simple of cells is placed in a salt solution. The cells shrink and the membrane is distorted. Relative to the cell, the solution is probably:
hypertonic
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cell of the celery stalks are
hypertonic to fresh water by hypotonic to the salt solution.
a molecules shape is _____
important to its funciton
What does the term antiparallel mean with respect to the arrangement of the two backbones that comprise the double-helix?
in DNA, two backbones run opposite 5' to 3' directions from each other
What types of adaptations for maintaining membrane fluidity do plants that adjust to extreme cold exhibit?
in many plants that tolerate extreme cold, such as winter wheat, the percentage of unsaturated phospholipids increases in autumn, an adaptation that keeps the membranes from solidifying during winter
What is cellulose? How does the structure of cellulose differ from that of starch?
in starch, all the glucose repeat units are oriented in the same direction. But in cellulose, each succesive glucose unit is rotated 180 degrees around the axis of the polymer backbone chain, relative to the last repeat unit
The inner mitochondrial membrane is folded into cristae. Why (think structure- function relationships here)?
increase the surface area
phosphate
makes the molecule of which it is a part an anion (negatively charged ion) and can transfer energy between organic molecules
methyl
non-polar, additional of a methyl group to DNA, or to molecule bound to DNA affects gene expression. arrangements of methyl groups in make and female sex hormones affects their shape and function
Glycine
nonpolar amino
When two atoms are equally electronegative, they will interact to form
nonpolar covalent bonds
Be able to distinguish among nonpolar, polar and electrically charged amino acids.
nonpolar: hydrophobic; the side chain contains a hydrocarbon alkyl group, or a benzene ring; polar: hydrophilic; any side chain that contains an acid, amide, alcohol, or amine electric: both; aspartic, glutamic, lysine, arginine, histidine
What is a nucleotide, polynucleotide?
nucleotide: polynucleotide made of monomers polynucleotide: nucleic acids that are polymers
What is molarity? How would you make a 0.5 M solution of fructose?
number of moles of solute per liter of solution - unit of concentration used most often by biologists for aqueous solutions find out the molecular mass of fructose. Then set 0.5 M equal to x grams/the molecular mass.
What does the atomic number tell you?
number of protons
Co-transport
occurs when active transport of a solute indirectly drives transport of another solute`
ATP: An Important Source of Energy for Cellular Processes
one phosphate moleculem adenosine triphosphate (ATP) is the primary energy-transferring molecule in the cell.
Gated Channel
open or close as a response to a stimulus
In the reaction shown here, a __ bond is formed.
peptide
the chemical reactions illustrated to the right results in the formation of
peptide bonds
define nuclear envelope
double membrane that surrounds the nucleus
Receptor Mediated Endocytosis
enables the cell to acquire bulk quantities of specific substances, even though these substances may not be very concentrated in the extracellular fluid
Glyceraldehyde is a triose that is the configurational standard for carbohydrates. The isomers D-glyceraldehyde and L-glyceraldehyde are shown to the right. Specifically, these two molecules are __.
enantiomers
What is meant by the term "free water concentration"? Why is the free water concentration an important consideration in understanding osmosis?
free water concentration - water diffuses across the membrane from the region of lower solute concentration to that of higher solute concentration until the solute concentrations on both sides of the membrane are equal
Which solute(s) will exhibit a net diffusion into the cell? The membrane is permeable to water, sucrose, and glucose but impermeable to lactose. The cell 0.02 lactose and 0.02 M sucrose and the environment is 0.01 M sucrose, 0.01 M glucose, and 0.01 M lactose
glucose
What are structural isomers?
have different covalent arrangements of their atoms
define amphipathic
having both hydrophilic and hydrophobic parts
define hypertonic
higher concentration of solutes (more salt)
which of the following solutions has the greatest concentration of hydroxide ions?
household ammonia at pH 11.5
What are the two major populations of proteins found in membranes and how do they differ from one another? To which population does a transmembrane protein belong?
peripheral proteins - bound to the surface of the membrane integral proteins - penetrate the hydrophobic core transmembrane proteins - integral proteins that span the membrane hydrophobic regions of an integral protein consist of one or more stretches of nonpolar amino acids, often coiled a-helices
The molecule shown is of the amino acid, tryrosine. Which functional group below is not present in this molecule?
phosphate
gycerol phosphate
phosphate
Consider the following ladder representation of DNA. The A and C represent different nitrogenous bases. The backbone is shown as alternating P and S blocks; P indicates ___ while S indicates ___.
phosphate ... sugar
What is a nucleic acid?
polymers called polynucleotides
What is a polypeptide?
polymers of amino acids
Acid precipitation
refers to rain, snow, or fog with pH lower than 5.6 - caused by mixing of different pollutants with water in the air - can damage life in lakes and streams
what is the relationship of an electron orbital to an electron shell?
represents the average distance between an electron and the shell and nucleus
Be able to distinguish among primary, secondary, tertiary and quaternary structures of proteins.
rimary: a protein is its unique sequence of amino acids secondary: found in most proteins, consists of coils and folds in the polypeptide chain tertiary: determined by interactions among various side chains (R groups) quaternary: results when a protein consists of multiple polypeptide
in a covelant bond, the _____ and ____ orbitals may _______, creating specific molecular shapes
s;p;hybridize
Molecular Mass
sum of all the masses of all the atoms in a single molecule - measured in Daltons (Da) or atomic mass units (u) where 1 Da= 1u= 1g/6.02x10^23= 1.660x10^-24g
what is the function of the nucleolus
takes part in production of ribosomes.
define tonicity
the ability of a surrounding solution to cause a cell to gain or lose water
what is specific heat of a substance?
the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1 degree celcius
define mass
the amount of matter in an object
what is an electron orbital?
the three-dimensional space where an electron is found 90% of the time
What does the mass number tell you?
the total number of protons and neutrons in the atom
define heat
the transfer of thermal energy
What is a membrane fluid?
the viscosity of the lipid bilayer of a cell membrane or a synthetic lipid membrane
Define membrane potential
the voltage difference across a membrane
Chloroplasts and mitochondrion have been termed semiautonomous organelles. Why?
they can feed and govern themselves and do not necessarily need the cell
If cattle lack the enzymes to digest cellulose, how can they extract nourishment from hay and grasses?
they harbor microbes that can digest cellulose
Distinguish among tight junctions, desmosomes and gap junctions. Which is analogous to the plasmodesmata of plant cells>
tight junctions membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid desmosome; anchoring junctions fasten cells together into strong sheets gap junctions; communicating junctions provide cytoplasmic channels between adjacent cells
Facilitated Diffusion
transport proteins speed the passive movement of molecules across the plasma membrane passive because solute moves down its concentration gradient
Exocytosis
transport vesicles migrate to the membrane, fuse with it, and release their contents used to export products
Describe the six major functions performed by membrane proteins
transport, enzymatic activity, signal transduction, cell to cell recognition, intercellular joining, and attachment to cytoskeleton and ECM
What is a protein?
tructural support, storage, transport, cellular communications, movement, and defense against foreign substances; account for more than 50% of the dry mass of most cells
What is a phospholipid? Why does it form a lipid bilayer (membrane) in aqueous solution?
two fatty acids and a phosphate group are attached to glycerol because when added to water they self-assemble with the hydrophobic tails pointing toward the interior
Define disaccharide
two simple sugars combined
define concentration gradient
unequal distribution particles (solute) in a solution
define anion
A negatively charged ion
The reactive properties or chemical behavior of an atom depend on the number of __.
Electrons in the outer valence shell in the atom
Interactions between what protein constituents are responsible for the formation of a protein's tertiary structure?
R groups
Which of the three components in question 42 above form the hydrogen bonded "rings" of the double helix?
a 5-carbon, or pentose, sugar (deoxyribose)
What is pH? How is it calculated? What is the relationship between the pH of a solution and the hydroxide ion concentration of that solution at 25 °C?
- Variation of H+ concentration can more easily be expressed by employing logarithms pH= -log [H+] - log 10^-7= -(-7)= 7
why does the surface of a liquid become cool as the liquid evaporates
- evaporative cooling of water helps stabilize temperatures in organisms and bodies of water - hottest molecules, with the greatest kinetic energy, are the most likely to leave as a gas
Why is water less dense as a solid than a liquid? What are the consequences of this property of water for the existence of life on Earth?
- hydrogen bonds are more ordered, making ice less dense - if ice sank, all bodies of water would freeze solid, making life impossible on Earth
What is a buffer and how does it function?
- internal pH of most living cells must remain close to pH of 7 buffer - substance that minimize changes in concentrations of H+ and OH- in a solution - most buffers consist of acid-base pair that reversibly combines with H+ H2CO3-> <- HCO3- + H+ - this acts as a pH regulator, shifting left or right, adding or removing H+
What is the concentration of the hydronium ion in pure water? The hydroxide ion?
- the concentration of each ion in water at 25 degrees C is 10^-7 M - The concentrations of H+ and OH- are equal
Why can even very large polar molecules such as proteins dissolve in water?
- water can also dissolve compounds made of nonionic polar molecules because water readily forms hydrogen bonds - even large polar molecules such as proteins can dissolve if they have ionic and polar regions
Which of the following can form a hydrogen bond with water?
-C=O and -NH2
Which of the following will not form a hydrogen bond(s)?
-CH3
What are some of the basic features of all cells?(both)
-Plasma membrane -Semifluid substance (cytosol) -Chromosomes (carry genes) -Ribosomes (make proteins)
sulfhydryl
-SH polar;two sulfhydryl groups can interact to help stabilize protein structure
describe cohesion
-Water binds to itself -Cohesion forms surface tension -Surface Tension can support small objects -Creates Viscosity
what is the relationship between heat absorption and release and the formation and breaking of hydrogen bonds?
-heat is absorbed when hydrogen bonds break - heat is released when hydrogen bonds form
The carbon atom is tetravalent; this means that ___.
A carbon atom can complete its valence shell by forming four covalent bonds
A enzyme is ___.
A catalyst, a protein, not consumed by a chemical reaction
Which cell would be able to diffuse substances from the interior of the cell to the exterior more rapidly?
A cell with a high surface area to volume ratio.
Which cell has properties better suited for the metabolic needs of diffusing substances most rapidly from the interior to the exterior of a cell (and vice versa)?
A cell with a surface area significantly greater then its volume.
define glycolipid
A complex lipid that contains carbohydrates and ceramides
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?
A hydrogen bond
What is a triacylglycerol?
A lipid made of three fatty acid and glycerol
Define surface tension
A measure of how difficult it is to stretch or break the surface of a liquid
An upper limit to the size of a cell is primarily a result of __.
A need for a high surface-to-volume ratio
Molecules capable of interacting in a chemical reaction must overcome a thermodynamic barrier known as the reactions __.
Activation energy
The movement of a substance across a biological membrane against its concentration gradient with the help of energy input is __.
Active transport
Transport processes across cellular membranes that require energy are ___.
Active transport
Which of the following statements describes the main difference between active and passive transport?
Active transport uses energy and passive transport does not.
The R group or side chain of the amino acid serine is -CH2-OH. The R group or side chain of the amino acid alanine is -CH3. Where would you expect to find these amino acids in a globular protein in aqueous solution?
Alanine would be in the interior, and serine would be on the exterior of the globular protein.
Although the structures of the functional groups that are most important to life vary, they share one thing in common: they __.
All are hydrophilic and increase the solubility of the molecule to which they are bound
A common characteristic of functional groups found in biological molecules is they __.
All are hydrophilic and increase the solubility of the molecule to which they are bound.
A common characteristic of functional groups found in biological molecules is they__.
All are hydrophilic and increase the solubility of the molecule to which they are bound.
Put the following molecules in order from smallest to largest molecular weight.
Amino acid, phospholipid, DNA, bacteria
Catabolic pathways __ complex molecules; they are dominated by __ reactions.
Break down .... Hydrolytic
Which of the following is a function of proteins in membranes?
Cell-cell recognition; provide a means for chemical signaling; transport large or hydrophilic molecules.
Monosaccharides have molecular formulas that are usually multiples of?
CH2O
Hydrophobic interactions __.
Can hold two nonpolar molecules together
Put the following atoms, which are in alphabetical order, in order of increasing number of protons in the element:
Carbon, Nitrogen, Oxygen
Which two functional groups are always found in amino acids?
Carboxyl and amino
what factor constrains the size to which a cell can grow
Changes in the surface area to volume ratio have important implications for limits or constraints on organism size, and help explain some of the modifications seen in larger-bodied organisms.(The requirements of carrying out cellular metabolism sets limits on the size of cells.)
What organelle is shown in the micrograph to the right? What is it's primary function?
Chloroplast ... sugar synthesis
Which of the following organelles is found in plant cells, but not in animal cells?
Chloroplast, central vacuole, cell wall
Grana, thylakoids, and stroma are components found __.
Chloroplasts
Which of the following are capable of converting light energy to chemical energy?
Chloroplasts
Which of the following relationships between cell structures and their respective functions is not correct?
Chloroplasts: chief site of cellular respiration
Which of the following relationships between cell structures and their respective functions is not correct?
Chloroplasts: chief sites of cellular respiration
Consider this fragment of a polypeptide. Which of the labeled atoms can be involved in secondary structure?
Circled atoms B and D
What is the DNA in a prokaryotic cell like?
Circular and not isolated from the cytoplasm
What are ribosomes
Compelxes made of ribosomal RNA and protein which are cellular components that cary out protein synthesis (create proteins).
A common mechanism to link monomers in covalent bonds to form polymers is ___.
Condensation/dehydration
In__ reactions, small molecules become covalently linked and water is formed.
Condensation/dehydration
A common mechanism to covalently link monomers to form polymers is __, which a common mechanism to break bonds linking monomers in polymers is __.
Condensation/dehydration ... hydrolysis
What is the correct description of the synthesis or degradation of macromolecular molecules?
Condensation/dehydration reactions extract a water molecule when forming a covalent bond. A hydrolytic reaction is often used when polymers are broken down into smaller units.
A nucleus __.
Contains most of the DNA in a cell
define nucleus
Control center of the cell
When two atoms interact, which atomic components are involved?
Electrons
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers, and hydrolysis breaks down polymers.
DNA is composed of __ and __ nitrogenous bases; while RNA is composed of __ and __ nitrogenous bases.
Deoxyribose..... A, G, C, T ...... ribose ..... A, G, C, U
Which of the following transport process(es) moves molecule down their concentration gradient?
Diffusion and facilitated diffusion
A polar covalent bond is a pairwise interaction between two atoms with ___ electronegativities. An example of a polar covalent bond is __.
Dissimilar ..... N-H
Prokaryotic cells differ from eukaryotic cells in that prokaryotic cells ___.
Do not have a nucleus
Diffusion moves molecules __ their concentration gradient __ added energy.
Down ... without
Of the following, which is probably the most common route for membrane flow in the endomembrane system?
ER-> vesicles-> Golgi-> plasma membrane
This is the electronic shell diagram of three of the most common elements in biological molecules. Which of the following statements is false?
Each of these atoms has a total of two electrons in the valence shell.
Are protists, fungi, animals, and plants prokaryotic or eukaryotic?
Eukaryotic
Regarding the size and shape of cells, which of the following statements in false?
Eukaryotic cells are often 100-1000 times larger then prokaryotic cells.
Which of the following difference between a prokaryotic and an eukaryotic cell is false?
Eukaryotic cells can synthesize proteins but prokaryotic cells cannot.
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells?
Facilitated diffusion
Which type of transport process requires transporter proteins embedded in the membrane?
Facilitated diffusion and active transport
Maltoporin is a protein in the outer membrane of some bacteria cells that form a narrow, hollow tube for maltose to pass through the membrane. Maltose is a disaccharide. Maltose is transported down its concentration gradient. What type of transport process is described here?
Facilitated diffusion, using a channel-type transport protein
what does the singer and nicolson fluid mosaic model state about membrane structure? what scientific evidence is there in support of this model?
In 1935 these 2 men suggested that the membrane might be coated on both sides with hydrophilic proteins. They proposed a sandwich model: A phospholipid bilayer between two layers of proteins. First inspection of a variety of membranes revealed that membranes with different functions differ in structure and chemical composition. A second, more serious problem became apparent once membrane proteins were better characterized. Unlike proteins dissolved in cytosol, membrane proteins were not very soluble in water because they were amphipathic. If such proteins were layered on the surface of the membrane their hydrophobic parts would be in aqueous surroundings. These two men proposed in 1972 that membrane proteins reside in the phospholipid bilayer with their hydrophilic regions protruding. This molecular arrangement would maximize contact of hydrophilic regions of proteins and phospholipids with water in the cytosol and extracellular fluid, while providing their hydrophobic parts with a non-aqueous environment.
what cell features can be used to distinguish a plant form an animal cell
In plant cells but not animal cells: Chloroplasts Central vacuole and tonoplast Cell wall Plasmodesmata
The solutions in the arms of a U-tube are separated by a selectively permeable membrane. The membrane is permeable to water but not to glucose. Side A is filled with a solution of 0.4 M glucose and side B is filled with a solution of 0.8 M glucose. Initially, the volume in both arms is the same. At equilibrium the water level __.
In side A will be lower than side B
In this schematic of an integral membrane protein, where would you expect to find hydrophobic amino acids?
In the section labeled 'B' but it is the tails or the middle section of the membrane
Which of the following statements about osmosis is false?
In turgid cells, the plasma membrane shrinks away from the cell wall.
Which of the statements regarding phospholipid bilayers is false?
Individual phospholipid are free to change sides of the bilayer.
What interactions define the tertiary structure of a protein?
Interactions between ---R groups of the amino acids
A chemical bond resulting from the attraction between oppositely charged ions in a (n) ___.
Ionic bond
A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism ___.
Is more closely related to frogs than to humans.
What are enantiomers?
Isomers that are mirror images of each other
What are cis-trans isomers?
Isomers that have the same covalent bonds but differ in spatial arrangements
Why is the valence shell important?
It determines many of an atoms chemical properties
The structural formula for galactose, a milk sugar, is shown to the right. How can this sugar be classified?
It is a hexose and aldose.
The structural formula for fructose, a monosaccharide often found in fruits, is shown to the right. How can this sugar be classified?
It is a hexose and ketose.
Ribulose is a saccharide that is an important precursor molecule for photosynthesis. Its structural formula is shown, how can this sugar be classified?
It is a pentose and ketose.
Which cell components are found in both prokaryotic and eukaryotic cells?
Plasma membrane Semifluid substance called the cytosol Chromosomes (carry genes) Ribosomes (make proteins)
A bond in which electrons are not shared equally is a __ bond.
Polar covalent
Consider this description of a bond. The interaction involves two atoms. The atoms share one electron between them. One of the atoms in the bond is more electronegative then the other atom. What type of bond is this?
Polar covalent bond
According to the fluid mosaic model of membrane structure, the mosaic part of the membrane is mostly __.
Proteins
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
Proteins
The atomic number of an element is the number of __ while the atomic mass is the number of __.
Protons ... protons and neutrons
Describe the relationship between the nucleus and ribosomes?
Ribosomes are made in the nucleus and ribosomes are used to carry out protein synthesis. They are composed of ribosomal nucleic acid and proteins.
which of the following set of cellular features are present in both prokaryotic and eukaryotic cells?
Ribosomes, plasma membrane, DNA
define thylakoids
Sacs of membrane with pigment molecules
Saccharides are composed of monomers of __ covalently attached by __ bonds.
Simple sugars .... Glycosidic
What kinds of molecules pass through a cell membrane most easily?
Small and hydrophobic
what are the two distinct regions of the ER called? how do they differ in funtion?
Smooth ER *its surface that faces the cytoplasm lacks ribosomes *it functions in detoxification of drugs *a major function is lipid synthesis Rough ER *its surface that faces the cytoplasm is studded with ribosomes *a major function is the manufacture of proteins Both *it forms vesicles that travel to other parts of the cell
In people who take large amounts of drugs to the point the compounds become toxic to that person, elevated levels of the following organelle involved in detoxification is often observed.
Smooth endoplasmic reticulum
Which of the following organelles is primarily involved in the synthesis of oils, phospholipids, and steroids?
Smooth endoplasmic reticulum
Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids?
Smooth endoplasmic reticulum
Discuss the sodium-potassium pump and the importance of protein shape.
Sodium potassium pump - exchanges sodium (Na) for potassium across the plasma membrane of animal cells this transport system pumps ions against steep concentration gradients: sodium ion concentration (represented as NA+ is high outside the cell and low inside, while potassium ion concentration is low outside the cell and high inside. The pump oscillates between two shapes in a pumping cycle that translocates 3 sodium ions out of the cell for every 2 potassium ions pumped into the cell. The 2 shapes have different affinities for the 2 types of ions. ATP powers the shape change by phosphorylating the transport protein ( by transferring a phosphate group to the protein )
Which of the following statements about water is true?
Statements A, B, and C are true
This image shows the structural formulas for sucrose and maltose. What type of isomer best describes these two molecules?
Structural isomers
define solute
Substance being dissolved
If a type of transport uses metabolic energy, which of the following statements also applies to the type of transport?
Substances are moved against the concentration gradient.
Anabolic pathways __ complex molecules, a common reaction in these pathways are __.
Synthesize .... Condensation
At which level of protein structure are interactions between R groups most important?
Tertiary
The geometric arrangement of 4 single covalent bonds around a C atom is a __.
Tetrahedral structure
The decomposition of an aqueous solution of starch has a negative delta G. At room temperature it does not degrade to monomeric sugar components because __.
The EA cannot be surmounted to most of the starch molecules
define energy
The ability to do work or cause change
What did Stanley Miller's experiment demonstrate? What does this suggest about the origin of life?
The abiotic synthesis of organic compounds is possible- could have been a stage in the origin of life.
The rate (speed) of a chemical reaction depends on __.
The activation energy, EA
Heat if vaporization
The amount of energy required for the liquid at its boiling point to become a gas
what happens when an atoms valence shell is full?
The atom is unreactive but complete/most stable point
Water is able to form hydrogen bonds because __.
The bonds that hold together the atoms in a water molecule are polar covalent bonds
What are functional groups?
The components of organic molecules that are most commonly involved in chemical reactions. The number and arrangement of the functional groups gives each molecule its unique properties.
The molecule shown is an amino acid, cysteine. The functional group indicated by the solid arrow is a __.
sulfhydryl
The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements is true?
The fluid component of the membrane is phospholipid, and the mosaic is protein.
Consider a cell that uptakes a particular molecule by simple diffusion. What is the effect of increasing the concentration of that molecule in the environment surrounding the cell?
The initial rate of diffusion will increase.
define denaturation
The irreversible, structural change in an enzyme that makes it unable to catalyse due to the substrate no longer fitting its active site.
The figure at right shows two isomers of C4H10. Which of the statements is true?
The isomers are structural isomers
If all the lysosomes within a cell suddenly ruptured, what would be the most likely result?
The macromolecules in the cytosol would begin to break down.
Why do fatty acids have limited solubility in aqueous solutions?
The majority of their bonds are nonpolar covalent carbon to hydrogen linkages.
What is the reason why hydrocarbons are not soluble in water?
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
What is the reason why hydrocarbons are not stable in water?
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
Nitrogen is much more electronegative than hydrogen. Which of the following statements is correct about the atoms in ammonia (NH3)?
The nitrogen atom has a partial negative charge.
Cells have a cytoskeleton of internal structures that contribute to the shape., organization, and movement of the cell. All of the following are part of the cytoskeleton except __.
The nuclear envelope
If a given chemical reaction is spontaneous, that means that __.
The reaction can occur without the net input of energy; the reaction is exergonic
Solution A of 5M glucose is separated from solution B containing only water by a membrane that is permeable to both glucose and water. At equilibrium, the concentration of glucose in solution A is __ in solution B: this is an example of __.
The same as ... diffusion
This is a diagram of a phospholipid. Which of the following statements is false?
The section labeled 'A' is buried in the interior of a lipid bilayer. The section labeled 'A' s buried in the interior of a lipid bilayer.
This image is of two sugars. How can they be best described?
The sugar on the left is a pentose and a ketone, the sugar on the right is a pentose and an aldehyde.
define polarity
The tendency of a molecule to be attracted to electric charges as a result of uneven electron sharing between atoms of different electronegativities.
The partial charges on a water molecule occur because of __.
The unequal sharing of electrons between the hydrogen and the oxygen atoms of a water molecule
What is the function of pili?
They allow a cell to attach to a substrate/other bacterial cells
proteins associated with membranes are what?
They are either hydrophobic and hydrophilic regions.
Which of the following statements about hydrophilic molecules is false?
They are found largely in oils.
Which of the following is (are) true for the class of large biological molecules known as lipids?
They are insoluble in water and they are an important constituent of cell membranes
Which of the following is (are) true in regard to lipids?
They are insoluble in water. They are an important constituent of cell membranes.
Which of the following is a false statement concerning amino groups?
They are nonpolar.
ethanethiol
sulfhydryl
Vinegar is a solution of dilute acetic acid with a pH of ~2.5. Wine typically has a pH of 3.5. Which of the following statements is true?
Vinegar is 10 times more acidic then wine.
Hydrophobic
Water fearing
In the cell when molecules are broken down to release energy, heat is also released. Water is able to maintain, of the buffer, temperature in cells better then almost any other liquid. What property of water best explains the temperature buffering capabilities of water?
Water has a high specific heat capacity.
Often when swimming in lakes at night, the water feels warmer than this temperature of the air. What property of water explains this phenomenon?
Water has a high specific heat capacity.
What property of water best explains why water striders (insects that are able to walk on the surface of water) can stand and walk on water?
Water has a high surface tension.
The moon and earth have similar distances to the sun. Two-thirds of the Earth's surface is water. Water is not observed on the surface of the moon. Which of the following statements best explains the role of water in the climate difference between moon and earth?
Water has a higher specific heat then the rocks on the moon; water absorbs large quantities of heat without raising temperature.
Which of the following would not pass readily through a lipid bilayer?
Water, glucose, sodium ion
Which of the following statements about osmosis is false?
When two solutions are isotonic, water molecules cease all movement through the membrane
Because of a cell's membrane potential, in which direction is the passive transport of cations favored? anions?
because the inside of a cell is negative with respect to the outside, cations (positive ions ) can enter the cell by passive diffusion anions (negative ions) can exit the cell by passive diffusion
what are weak bonds important in biology?
because weak bonds reinforce shapes of large molecules and help molecules adhere to eachother
carbonyl
carbon double bonded to an oxygen, the position has determined the properties, a ketone and an aldehyde may be a structural isomers with different properties
aceton the simplest ketone
carbonyl
acetic acid
carboxyl, has acidic properties because it is a source of hydrogen ions
Phagocytosis
cell engulfs particle by wrapping pseudopodia around it and packaging it within a membrane enclosed sac that can be large enough to be classified as a vacuole. The particle is digested after the vacuole fuses with a lysosome containing hydrolytic enzymes
Pinocytosis
cell gulps droplets of extracellular fluid into tiny vesicles. It is not the fluid itself that is needed by the cell, but the molecules dissolved in the droplets. Because any and all included solutes are taken into the cell, pinocytosis is nonspecific in the substances it transports
Endocytosis means? And what 3 other forms occur?
cell takes in macromolecules by forming new vesicles from the plasma membrane; uses different proteins others: phagocytosis, receptor mediated endocytosis, and pinocytosis
define phagocytosis
cellular eating
the main function of the organelle shown here is ___.
cellular respiration and ATP formation
Enzymes that digest starch cannot digest cellulose. Why?
cellulose doesn't dissolve in water the way starch will, and doesn't break down as easily, therefore making it unable to digest
what is the function of plasmodesmate? why are they particulary important for plant cells?
channels that perforate plant cell walls water and small solutes land sometimes protiens and RNA can pass from cell to cell
2 combined forces of a chemical force (concentration gradient) and electrical force (effect of membrane potential on ion movement) that drive the diffusion of ions across a membrane
chemical force (ion's concentration gradient) electrical force (the effect of membrane potential on ion's movement)
what organelle is shown in the micrograph to the right? what is it's primary function?
chloroplast ... sugar synthesis
The presence of cholesterol in the plasma membranes of some animals
decreases membrane fluidity at warm temperatures. Enables the membrane to stay fluid more easily when cell temperature drops.
Hydrogen bonding between what protein constituents is responsible for the formation of a protein's secondary structure?
denatured protein: biologically inactive; loss of proteins native conformation
Which of the above components are linked to form the nucleic acid backbone?
deoxyribose/pentose (DNA)
What determines the properties of an amino acid?
differing side chains called R groups
what is "osmosis"
diffusion of water
define potential energy
energy of position
What type of linkage joins a fatty acid to a glycerol molecule?
ester linkage
What type of cell is shown here?
eukaryote
Crossing a membrane by simple diffusion can be distinguished from facilitated diffusion because:
facilitated diffusion requires transport proteins while diffusion does not
What is a chloroplast? In which cell type would it be found? What is its function? Draw a chloroplast and label all its parts.
found in leaves and other green organs of plants and in algae plant cells contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosysntheis
what is the extra cellular matrix of an animal cell and what are its functions?
intercelluar junction; most cells syntheis and secrete materials that are external to the plasma membrane it's frictions are support, adhesion, movement, regulation
The tertiary structure of a protein is defined by:
ionic bonds between amino acid side chains; hydrogen bonds between amino acid side chains; hydrophobic interactions of amino acid side chains
when an ____ compound is dissolved in water, each ion is surrounded by a sphere of water molecules, an hydration shell.
ionic compound; due to the solvent: H2O in this case because of the polarity of the molecule.
what is a lysosome? In which type of cells is it found? What does it do?
is a membranous sac of hydrolytic enzymes found in animal cell, can hydrolyze proteins, fats, polysaccharides, and nucleic acids, use enzymes to recycle organelles and macromolecules in autophagy.
what is the cytoskeleton? what is its function? what are the different structures that comprise the cytoskeleton?
is a network of fibers extending throughout the cytoplasm it organizes the cells structures and activities anchoring many organelles 1. microtubules (thickest) 2. microfilaments (thinnest) 3. intermediate filaments (middle, rangel)
which of structures contains an amino functional group?
it has to have an NH, or NH2
tubulin is a polymer. what protein subunits is it constructed from? What type of structure does it form?
it is composed of a tubulin and b tubulin, and it forms microtubules
what is the significance of the cross-linking between microtubules in a cilium or flagellum?
it is limits sliding
Water passes quickly through cell membranes because
it moves through aquaporins in the membranes
what is a peptide bond?
link amino acids
The __ portion of the cell membrane functions as a barrier while the ___ portion determines specific functions, including pumps, receptors, adhesion, etc.
lipid ..... protein
What is a steroid? Name an important steroid found in animal cell membranes
lipids characterized by a carbon skeleton consisting of four fused rings cholesterol
Why are most unsaturated fats liquids at room temperature?
liquid
define stroma
liquid surrounding thylakoids; contains enzymes for PS
define hypotonic
lower solute concentration
Molar Mass
mass of 1 mole of a given substance. Since there are 6.02 x 10^23 Da in one gram, e can simply replace the units of one Da by grams to express the molar mass
define voltage
measure of potential energy generated by separated charge
What is a vacuole? What is its function? In which kind of cell would you find one?
membrane- bound sacs with varies functions you would find this in a plant cell, or fungal cell
When a vesicle fuses with the plasma membrane which layer of the vesicle (outside or inside) becomes continuous with the outside face of the plasma membrane? Was this face originally on the outside or inside of the ER?
membranes have distinct inside and outside faces. The 2 lipid layers may differ in specific lipid composition, and each protein has directional orientation in the membrane when a vesicle fuses with the plasma membrane, the outside layer of the vesicles becomes continuous with the cytoplasmic (inner) layer of the plasma membrane. Therefore molecules that start out on the inside face of the ER end up on the outside face of the plasma membrane
what is the centrosome? What structure is found in the centrosome of animal cells?
microtubule organizing center each centrosome has a pair of centroles each with 9 triples of microtuble arranged in a ring
What are Van der Waals forces?
molecules that are very close together can be attracted by fleeting charged differences its a weak attraction but in bulk can be very strong
how does dehydration contribute to the formation of marcromolecules
monomers that form larger molecules by condensation; removes a water molecule forming a new bond
The structure of ATP is shown. which of the following statements regarding ATP is false?
most of the energy stored in ATP is contained in the OH bonds.
define diffusion
movement of molecules from high concentration to low concentration
Active Transport
moves substances against their concentration gradient; allows cells to maintain concentration gradients that differ from their surroundings; requires energy in the form of ATP
What is the basis for labeling the carbons of the ring form?
nitrogen bases
5-methylcytosine
produced by DNA methyltransferase after replication
Are organisms of the domains bacteria and archea prokaryotic or eukaryotic?
prokaryotic
Define glycoprotein
protein attached to a carb, involved in immune response
What is a chaperonin and how does it work?
protein molecules that assist the proper folding of other proteins 1.an unfolded polypeptide enters the cylinder from one end 2.the cap attaches causes the cylinder to change shape in such a way that creates a hydrophilic environment for the folding of the polypeptide 3.the cap comes off and the properly folded protein is released
what are subatomic particles that comprise an atom?
protons, neutrons and electrons
Channel Proteins
provide corridors that allow a specific molecule or ion to cross the membrane
What is a covalent bond?
strongest bond, an unequal amount of electrons shared between atoms (usually polar and partial charged)
what is the molecule illustrated here?
saturated fatty acid
What is the difference between a saturated fatty acid and an unsaturated fatty acid?
saturated: have the maximum number of hydrogen atoms possible and no double bonds unsaturated: have one or more double bonds
What are the two primary functions of monosaccharides
serve as major fuel for cells and raw material for building molecules
define double bond
sharing two pairs of valence electrons is a double covalent bond
Define monosaccharide
single sugar molecule
What is the molecular logic of life?
small molecules common to all organisms are ordered into unique macromolecules
What is the physical state of most saturated fats at room temperature?
solid
Two solutions are separated by a semi-permeable membrane. Solution 1 has 5 M glucose and 5 M sucrose, Solution 2 has 5 M glucose. Water and glucose are permeable, while sucrose is impermeable. At equilibrium ___. Solution 1: 5 M glucose and 5 M sucrose Solution 2: 5 M glucose
solution 1 will have a higher water level than Solution 2.
what is a peroxisome and what is its function?
specialized metabolic compartments bound by a single membrane hydrogen peroxide (H2O2) and convert it to water
what accounts for the relatively high heat of water?
specific heat is high because heat is absorbed when hydrogen bonds break and also because heat is released when hydrogen bonds form
define granum
stack of thylakoids
What are the differences between starch and glycogen?
starch is implants and glycogen is in animals
What are the primary biological roles of polysaccharides?
storage: sugars (plants and animals), starch (plants) consists entirely of glucose monomers, and glycogen (animals)
Describe the cisternal maturation model? What does it attempt to explain?
the cisternae of the golgi actually move forward from the cis to trans face, carrying and modifying their cargo as they move
define kinetic energy
the energy an object has due to its motion
consider this image of a cell which of the following statements is false?
the letter 'C' indicates a mitochondria
Why can cellulose form microfibrils and starch cannot?
the microfibrils of cellulose are extremely tough and inflexible due to the presence of hydrogen bonds
What is the atomic number?
the number of protons in an atom
What is a lipid? What two types of smaller molecules are fats constructed from?
the one class of large biological molecules that do not form polymers; have little to no affinity for water; hydrophobic because they consist mostly of hydrocarbons, which form non-polar covalent bonds 1.phospholipids 2.steroids
What does solidification mean with respect to a membrane? Why is it detrimental to the cell? What determines the temperature at which a membrane solidifies? How and in what ways does cholesterol act as a temperature "buffer" when incorporated into a membrane?
the point reached as temperature decreases; the temperature at which a membrane solidifies depends upon the lipid composition of that membrane cholesterol can act as a "temperature buffer"; the steroid cholesterol, which is wedged between phospholipid molecules in the plasma membranes of animal cells, has different effects on membrane fluidity at different temperatures at relatively high temperatures at 37 C, the body temperature of humans, for example, cholesterol makes the membrane less fluid by restraining phospholipid movement. However, because cholesterol also hinders the close packing of phospholipids, it lowers the temperature required for the membrane to solidify. Thus, cholesterol can be thought of as a "fluidity buffer" for the membrane, resisting changes in membrane fluidity that can be caused by changes in temperature
Molecules that are too large or too hydrophilic to pass through a lipid bilayer are still able to enter and exit the nucleus. How is this accomplished?
the pore complex in the nuclear pores regulates the entry and exit of most proteins and RNAs, as well as large complexes of macromolecules
What ultimately determines the selective permeability of a membrane?
the selective permeability of a membrane depends on both the discriminating barrier of the lipid bilayer and the specific transport proteins built into the membrane
What is a mitochondrion? What is its function? Draw a mitochondrion and label all its parts.
the site of cellular respiration and are found in nearly all eukaryotic cells they generate chemical energy
define solvent
the substance that dissolves the solute
what is the outermost electron shell called?
valence shell
describe ability to moderate temperature
water absorbs heat from warmer air and releases stored heat to cooler air. water can absorb or release a large amount of heat with only a slight change in its own temperature.
define aquaporin
water channel protein in a cell
describe expansion upon freezing
water is less dense as a solid than as a liquid. water expands when it solidifies and ice floats in liquid water. the ice floats in the liquid water becuase hydrogen bonds in ice are more "ordered" making ice less dense.
define hydrophilic
water loving
Do both prokaryotes and eukaryotes have DNA?
yes
Are ribosomes present in both eukaryotes and prokaryotes?
yes, they synthesis protiens