Bio Quiz 3
Functional groups of glucose and fructose
*Carbonyl group* (but different classes within the group) *glucose* - the aldehyde isomer *fructose*, the ketone isomer
List two major differences between a typical plant cell and a typical animal cell.
*Cell wall:* Protection, structural support *Central vacuole:* Cell growth, support, and storage; contains enzymes for digestion of many complex molecules *Chloroplast: *Photosynthesis; some starch storage
Billions of years ago, life apparently arose from inorganic chemicals, but all life today apparently arises only by the reproduction of preexisting life. If life could come from nonlife on the ancient Earth, can you think of one major reason why this does not continue to happen today?
*Consider a potential problem with oxygen* The presence of O2 provided life with new opportunities. Aerobic metabolism is more efficient than anaerobic pathways, and the presence of oxygen undoubtedly created new possibilities for life to explore The concentration of oxygen in the atmosphere is often cited as a possible contributor to large-scale evolutionary phenomena
One difference between eukaryotic and prokaryotic cells is the presence of _____ in eukaryotes and its absence in prokaryotes
*Golgi apparatus*
Describe the differences between ionic, polar covalent, and non-polar covalent bonds. Are electrons being transferred or shared? If shared, equally or unequally?
*Ionic*: result from electrical attractions between atoms that gain or lose valence electrons completely *Covalent*: form when atoms share a pair of valence electrons rather than gaining or losing them • *polar covalent:* electrons are shared unequally; the atom that attracts the electrons more strongly carries a partial negative charge and the atom deprived of electrons carries a partial positive charge, • *non-polar covalent bonds*: electrons are shared equally or nearly equally
What is the difference between the tertiary and quaternary structure of a protein?
*Tertiary* contains one polypeptide chain wheres *Quaternary* contains more than one polypeptide chains
*Takeaway from the Miller-Urey experiment*
*The Miller-Urey experiment provided the first evidence that organic molecules needed for life could be formed from inorganic components.*
Autotrophic vs heterotrophic
*heterotrophic* = can't make it's own food (ie fungi) *autotrophs* - make their own food (ie plants)
Lyme Disease
- bacteria transmitted from one cell to another -Spirochaete bacteria- found that causes disease and can be treated with antibiotics. -bacteria lives in tick gut -tick pics up bacteria when it gets on fox, deer, squirrels etc.. tick gets bacteria from mammal -tick burrows in animal, releases anesthetic, sucks blood, but also releases bacteria in it's gut while it sucks blood -humans are a side/ dead end host -symptoms- late stages of Lyme Disease - neurological/ psychiatric
Prokaryotic Cells
- generally a bacteria cell - bacteria cells 3.5 billion years old (most bacteria are benign) - characteristics of both an animal an plant cell i.e plasma membrane and cell wall Prokarytics have a cell wall 1. Capsule 2. Cell Wall 3. Cytoplasmic Membrane Enclose cytoplasm (liquid) Unique to prokaryotic cells: -organelles float around in cytoplasm -DNA floats are NOTT a chromosome ?
Carbohydrates
- molecules in which carbon, hydrogen, and oxygen occur in the approximate ratio 1:2:1. - Two monosaccharides join to form a disaccharide; greater numbers form polysaccharides Energy-providing carbohydrates are stored in plant cells as *starch* and in animal cells as *glycogen* *cellulose*, one of the primary constituents of plant cell walls. *monosaccharides* i.e glucose *disaccharide* 2 monosaccharides polymerize i.e sucrose *polysaccharides* - 10 ore more monosaccharides ie Starch, glycogen, cellulose
Penecilin
-Flemming -microbiologist studying fungi and bacteria -antibiotics are often fungi
*Characteristics of living things*
1. complexity and organization ie. Living things organize cells at several levels: Tissue, Organ , Organ system, Organism 2. response to stimuli (has adaptive value) i.e. a person touches hot stove 3. growth 4. homeostasis - "steady state" - condition in which everything is stable for an animals survival i.e. turtle moving in sun to stay warm 5. metabolism - taking in of raw material for energy 6. reproduction: *asexual:* bacteria splits in half no need for sperm and egg *sexual:* need for sperm and egg -provides variability 7. capacity to evolve **Note: All of the above NEED to be present to have a living organism
Nucleotide
3 components of nucleotide: nitrogenous base, deoxyribose(sugar) and phosphate group Nucleotides form the basic structural unit of nucleic acids such as DNA. - serve as the monomer units for forming the nucleic acid polymers for DNA and RNA
ribozyme
An RNA-based catalyst that is part of the biochemical machinery of all cells
DNA double helix
Arrangement of sugars, phosphate groups, and bases in the DNA double helix. The dotted lines between the bases designate hydrogen bonds.
How can a change in pH of the solution affect the structure shown above? Consider increasing concentration of OH- or H+ ions in the solution as pH changes. How will these full charges interfere with the bonds shown in the figure above?
Changes in pH change the attractions between the groups in the side chains of the protein The interactions between the side chains of the amino acids determine the shape of a protein Small changes in pH can add or remove H+ ions from side chain groups on the surface of a protein Interactions between the side chains in the amino acids making up proteins causes them to fold into a unique three-dimensional shape. Changing the pH level alters these side-chain interactions, leading to a change in protein structure and therefore the activity, of a protein
Organic Molecules Formed by Chemical Evolution
Chemical evolution occurred as a result of reactions involving inorganic molecules present on primordial Earth • atmosphere lacked oxygen and contained hydrogen, methane, ammonia, and water. • Energy for the chemical evolution reactions came from solar energy and other natural sources, such as lightning and volcanic activity. A classic laboratory simulation experiment of chemical evolution was performed in 1953 by Stanley Miller and Harold Urey. •Using an apparatus they designed, they achieved the synthesis of complex organic molecules from methane, ammonia, water, and hydrogen
Review the structures for *Fructose and Glucose*. They have the same chemical formula and the same functional groups. How come they are considered two different sugars?
Fructose and Glucose have the *same chemical formula* and the *same functional groups*, but they are considered two *different sugars* because • they are *Structural isomers* - two molecules with the same chemical formula but *atoms that are connected in different ways* Glucose and fructose, structural isomers of a six-carbon sugar with the chemical formula C6H12O6. (A) In *glucose*, the aldehyde isomer, the carbonyl group (shaded region) is located at the end of the carbon chain (B) In *fructose*, the ketone isomer, the carbonyl group is located inside the carbon chain
Gogli Complex
In eukaryotes, the organelle *responsible for the final modification, sorting, and distribution of proteins and lipids*
Cell junctions
Junction that fills the spaces between cells and provides direct communication between cells
Oxygen poor atmosphere and how life formed (don't need to know)
Oparin and Haldane thought that the early Earth had a reducing atmosphere, meaning an oxygen-poor atmosphere in which molecules tend to donate electrons. Under these conditions, they suggested that: Simple inorganic molecules could have reacted (with energy from lightning or the sun) to form building blocks like amino acids and nucleotides, which could have accumulated in the oceans, making a "primordial soup." ^3 3 start superscript, 3, end superscript The building blocks could have combined in further reactions, forming larger, more complex molecules (polymers) like proteins and nucleic acids, perhaps in pools at the water's edge. The polymers could have assembled into units or structures that were capable of sustaining and replicating themselves. Oparin thought these might have been "colonies" of proteins clustered together to carry out metabolism, while Haldane suggested that macromolecules became enclosed in membranes to make cell-like structures^{4,5}
ribisome
Ribosomes are a cell structure that makes protein
Miller-Urey Experiments 1950's (famous experiment)
They designed an apparatus which held a mix of gases similar to those found in Earth's early atmosphere over a pool of water, representing Earth's early ocean. Electrodes delivered an electric current, simulating lightning, into the gas-filled chamber. After allowing the experiment to run for one week, they analyzed the contents of the liquid pool. They found that several organic amino acids had formed spontaneously from inorganic raw materials. *purpose:* chemical experiment that simulated the conditions thought at the time to be present on the early Earth, and tested the chemical origin of life under those conditions. theoretical early earth consisted of: 1. atmosphere: CH4, NH3, H2O, H2 gasses 2. No O2 3. liquid water The experiment used water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2). bombarded with electrical energy -earth was a "soup" -formaldehyde (CH2O) -hydrogen cyanide (important for amino + nucleic acid) -formic acid (Sp?) (HCOOH) -some amino acids -urea - waste product of human activity
Condensation/Dehydration synthesis
a *peptide bond*, is formed by a *dehydration synthesis (also known as a condensation reaction)* reaction between the amino group of one amino acid and the carboxyl group of a second, releasing a molecule of water (H2O).
common functional groups
a. hydroxyl group (-OH), b. carbonyl group (-C==O *carbon double bonded to oxygen*) c. carboxyl group (COOH) d. amino group (NH2) e. Sulfhydryl (not shown Phosphate PO4 2-)
Which is a basic functional group that can accept H+ and become positively charged?
amino group (NH2)
shared organelles between plant and animal cells
both have ribosomes
Draw the basic structure of an amino acid that has a methyl group as its variable side chain.
called "Alanine" *methyl group* = one carbon atom bonded to three hydrogen atoms = CH3.
Which is an acidic functional group that can dissociate and release H+ into a solution?
carboxyl group
How did Miller and Urey know which gases to include and which ones to exclude for their experiment? *The Miller-Urey experiments excluded oxygen gas. Explain why.*
composition of the atmosphere of the early earth: *water (H2O), methane (CH4), ammonia (NH3), and hydrogen (H2)* *Scientists believe that the Earth was formed about 4.5 billion years ago. Its early atmosphere was probably formed from the gases given out by volcanoes. It is believed that there was intense volcanic activity for the first billion years of the Earth's existence. The early atmosphere was probably mostly carbon dioxide with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane.* For decades, scientists believed that the atmosphere of early Earth was highly reduced, meaning that oxygen was greatly limited. Such oxygen-poor conditions would have resulted in an atmosphere filled with noxious methane, carbon monoxide, hydrogen sulfide, and ammonia.
What is the difference between the two units in item III above?
double bond in the fatty acid chain ("kink") Unsaturated fatty acid chains tend to bend or "kink" at a double bond (making the chains more disordered and thus more fluid at biological temperatures)
DNA and RNA
double helix with two polynuceotide strands RNA - carries the instructions for assembling proteins from DNA to the sites where the proteins are made inside cells
Seeding Hypothesis
early forms of life were "seeded" with a comet or asteroid hitting the earth • theory is not meant to address how life began, just the method that may cause its distribution in the Universe • proposes that microscopic life forms that can survive the effects of space, such as extremophiles, become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life • If met with ideal conditions on a new planet's surfaces, the organisms become active and the process of evolution begins.
Why is a change in the C 12: C 13 ratio about 3.7 BYA considered to be evidence for life?
enzymatic reactions discriminate against the heavier isotope When: - earth formed about 4.5 BYA - radiometric dating of the oldest known rocks 3.9 BYA -chemical indicator of organic synthesis *C12:C13 Ratio* -living organisms exhibit a preference for Carbon-12 over Carbon-13 because the the C13 isotope has an additional neutron and more mass, and enzymatic reactions discriminate against the heavier isotope *Since organisms take up C12 in preference to C13, the ratio is used to determine whether or not the carbon in the specimen is of biological origin* - Living organisms "prefer" C12 (although inorganic reactions do not discriminate between the two) -about 3.5 BYA deposits have high C12 to C13 ratio • all atoms of an elements have the same atomic # (however, some differ in mass #) -the variations are isotopes: same # of protons and electrons but different # of neutrons -unlike C12, C14 is unstable (radioactive - gives off energy +heat) - atoms like to be stable -Carbon has two stable/ non-radioactive forms C12 and C13. C14 is radioactive
Central Vacuole
found only in plants cells -functions to hold materials and wastes - also functions to maintain the proper pressure within the plant cells to provide structure and support for the growing plant
Lipids
hydrocarbon-based, water-insoluble, nonpolar molecules. Biological lipids include neutral lipids, phospholipids, and steroids
What kind of chemical bond is involved in forming the secondary structure of a protein? *What is holding the shape of alpha helices or beta pleated sheets?*
hydrogen bonds The alpha helices and beta pleated sheets are held together by *hydrogen bonds*
Proteins
macromolecules that perform many vital functions in living organisms Proteins are assembled from 20 different amino acids. Amino acids have a central carbon to which is attached an amino group, a carboxyl group, a hydrogen atom, and a side group (R) that differs in each amino acid
amino acid
molecule that contains both an amino and a carboxyl group - cells of all organisms use 20 different amino acids as the building blocks of proteins - Differences in the side groups give the amino acids their individual properties
What is the pH of a solution with a hydrogen ion [H+] concentration of 10-8 M?
pH 8
phospholipid
phospholipids orient with their polar end facing the water and their nonpolar ends clustered in a region that excludes water -provide the structure for membranes - zigzag lines represent the nonpolar fatty acid chains
mitochondria
produce energy for cells -ATP
mitochondria
produce the energy currency of the cell, ATP through respiration - regulate cellular metabolism.
ER (endoplasmic reticulum)
protein synthesis and protein transport
Endoplasmic reticulum
responsible for the synthesis transport and *initial* modification of proteins and lipids
What kind of chemical bond is involved in forming the primary structure of a protein? What type of bond is a peptide bond?
sequence of amino acids joined by *peptide bonds* in a polypeptide chain a *peptide bond*, is formed by a *dehydration synthesis (also known as a condensation reaction)* reaction between the amino group of one amino acid and the carboxyl group of a second, releasing a molecule of water (H2O).
functional groups
specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules • same functional group will undergo the same or similar chemical reaction(s) • attached to Carbohydrates, lipids, proteins, and nucleic acids
mass number of an element
total number of protons and neutrons in a nucleus.
centrioles
used in cell division
β pleated sheet secondary structure of a polypeptide.
• type of secondary structure in proteins Hydrogen bonds between adjacent b strands stabilize the sheet, making it a highly rigid structure. Beta sheets may lie in a flat plane or may twist into propeller- or barrel-like structures.
α helix secondary structure of a polypeptide
• type of secondary structure in proteins • (Ball-and-stick model of the a helix. The backbone of the amino acid chain is held in a spiral by hydrogen bonds formed at regular intervals between backbone atoms. • The cylinder often is used to depict an a helix in protein diagrams; peptide and hydrogen bonds may also be shown
