Biology Midterm
Which of the following is TRUE with regard to a DNA molecule ?
The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine.
Identify which cellular structure controls the flow of materials into and out of cells.
The composition of the plasma membrane relates to its job as a border guard, regulating the flow of materials into and out of the cell.
Explain how an electron microscope works and compare/contrast with a light microscope. What are the benefits and disadvantages of each?
The electron microscope (EM) uses a beam of electrons, which results in 100-fold better resolution than light microscope. Two kinds of electron microscopes reveal different parts of cells. Both use radiation (light or electron beams) to form larger and more detailed images of objects. Light microscope-higher resolution, higher magnification, used with living cells electron microscope is not
Describe the role of activation energy in a chemical reaction and explain how enzymes affect activation energy.
The energy that must be invested to start a reaction is called activation energy because it activates the reactants and triggers the chemical reaction. An enzyme speeds the chemical reaction by lowering the activation energy barrier.
List the reactants and products in photosynthesis. Identify the main purpose for photosynthesis. What is the primary product? What is the waste product or byproduct of photosynthesis?
The main purpose of photosynthesis is to convert radiant energy from the sun into chemical energy that can be used for food. Reactants : carbon dioxide CO2 and water H20 Products : glucose C6H12O6. and oxygen O2 (primary product is glucose, waste product is oxygen
Why is water considered a polar molecule ?
The oxygen end of the molecule has a slight negative charge, and the hydrogen end has a slight positive charge.
Why is water considered a polar molecule?
The oxygen end of the molecule has a slight negative charge, and the hydrogen end has a slight positive charge.
The light reactions are generally presented in zig-zag patterns, as shown in the accompanying figure. What is the significance of the primary electron receptor shown at position 2 being slightly higher than the primary electron receptor shown at position 3?
The primary electron receptor at 2 has slightly less energy than the primary electron receptor at position 3.
Explain the relationship between wavelength and amount of energy. Do longer or shorter wavelengths of light contain more energy?
The shorter the wavelengths and higher the frequency corresponds with greater energy. So the longer the wavelengths and lower the frequency results in lower energy.
A balloon permeable to water but not to glucose contains a 10% glucose solution. A beaker contains a 5% glucose solution. Which of the following is TRUE?
The solution in the balloon is hypertonic relative to the solution in the beaker.
Why (if you are careful) are you able to float a needle on the surface of water?
The surface tension that is a result of water's cohesive properties makes this possible
Which of these results would you predict to occur if climate change results in increased warming global temperatures?
The tree line (at which it is too cold for trees to grow) moves toward the north and south poles.
How do hypotheses differ from theories ?
Theories are more comprehensive than hypotheses.
Examine the two sugars in the following figure. How do these two sugars compare?
They have the same formula but different structures
Explain how the food we eat is converted to usable energy by cells.
Through cellular respiration, the energy in food is converted into energy that can be used by the body's cells. During this, glucose and oxygen are converted into carbon dioxide and water, and the energy is transferred to ATP.
Tobacco smokers (and those exposed to tobacco smoke) are at greater risk of an ectopic (tubal) pregnancy. Based on your understanding of the structures of the cytoskeleton, what is the best explanation?
Tobacco interferes with the sweeping motion of cilia that aids in the movement of the egg toward the uterus.
List all the organelles found in an animal cell and list all the organelles found in a plant cell. Which organelles are found in animal cells, but not in plant cells? Which organelles are found in plant cells but not in animal cells?
Unlike animal cells, plant cells have 1. chloroplasts, which convert light energy to the chemical energy of food in the process of photosynthesis, and 2. protective cell walls. Only animal cells have lysosomes, bubbles of digestive enzymes surrounded by membranes Plant cells usually have one or more large vacuole(s), while animal cells have sometimes smaller ones
Explain what we mean when we say electrons are "falling". How are they "falling"? What important event occurs concurrently as electrons "fall"?
When electrons move from glucose to oxygen, it is as though the electrons were falling. This "fall" of electrons releases energy during cellular respiration.
Amino acids include a side group as well as _____
a central carbon, a hydrogen atom, an amino group, and a carboxyl group
A horse eating some hay is an example of _____
a consumer eating a producer
The nuclear envelope is composed of
a double membrane
Plants are susceptible to bacterial infections, which can damage their structure or even kill them. Which of the following would be the best antibiotic to treat a plant that infected with bacteria?
a drug that blocks gene expression in circular chromosomes
Which of the following is most like a signal transduction pathway in a cell?
a person answering the door to their home after someone rings the doorbell
The figure below shows
a single strand of DNA
What is a gene?
a unit of inheritance
Describe what features prokaryotic and eukaryotic cells have in common.
a. They are all bounded by a thin plasma membrane. b. Inside all cells is a thick, jelly-like fluid called the cytosol, in which cellular components are suspended. c. All cells have one or more chromosomes carrying genes made of DNA. d. All cells have ribosomes, tiny structures that build proteins according to the instructions from the DNA.
What must pyruvic acid be converted to before it can enter the citric acid cycle ?
acetyl CoA
The region of an enzyme to which a substrate binds is called the ______ site.
active
Which of the following processes could result in the net movement of a substance into a cell, if the substance is most concentrated in the cell than in the surroundings?
active transport
In what way(s) is the science of biology influencing and changing our future ?
all of the above (by helping us understand the relevance of evolution to human health, by revealing how mutations in genes can lead to disease, by providing new tools for forensic investigations)
Which of the following is a way that a molecule releases energy gained by absorption of a photon?
all of the above (heat, fluorescence, light)
Which of these is required for natural selection to occur
all of the above (inheritance, unequal reproductive success, individual variation)
Microtubules are associated with _____
all of the answer choices (cilia, flagella, cell shape)
Active transport _____
all of the answer options (uses ATP as an energy source,) can move solutes against their concentration gradient, can involve the transport of ions)
Proteins are polymers constructed from _____ monomers.
amino acid
A friend of yours appears to have put on a lot of muscle very quickly. At the same time, you notice that your friend seems to have a lot of mood swings and appears depressed. It is reasonable for you to suspect that your friend has begun to take _____
an anabolic steroid
The way Earth moves about the sun is most like _____
an electron moving around the nucleus of an atom
Identify the types of molecules capable of hydrogen bonding.
any molecule which has a hydrogen atom attached directly to an oxygen or a nitrogen
Some ribosomes are suspended in the cytosol of a cell, whereas other ribosomes _____
are attached to the outside of the nucleus
What accounts for the different breeds of domesticated dogs ?
artificial selection
Use a periodic table to identify a given element's atomic number and atomic weight, and then use these numbers to determine how many protons, neutrons and electrons an average atom of this element contains.
atomic number= number of protons weight= protons+neutrons number of protons equal number of neutrons in a neutral element
A hormone that will be secreted from the cell is manufactured by ribosomes _____.
attached to the endoplasmic reticulum
In a hypotonic solution, a plant cell will _____
become turgid
Which of the following is lowest in unsaturated fats?
beef
If a plant appears blue to us, what wavelength of light is being reflected?
blue
What name is given to substances that resist changes in pH ?
buffers
Explain how a buffer is able to maintain the pH of a solution constant despite addition of acid or base to the solution
by accepting or donating H+ ions based on the specific circumstances
How does taxonomy assist biologists?
by categorizing diverse items into smaller and smaller numbers of groups
Explain how neutral atoms become ions.
by gaining or loosing electrons
Carbohydrates typically include
c, h and o atoms
Unequal reproductive success _____
can lead to natural selection
Match each of the macromolecules described in your textbook, (carbohydrates, lipids, proteins, nucleic acids), with their corresponding building blocks.
carbohydrates- monosaccharides lipids- fatty acids, glycerol, proteins- amino acid nucleic acid- nucleotide
Which of the following are produced during cellular respiration?
carbon dioxide, water, and ATP
The four most common elements found in living organisms
carbon, oxygen, nitrogen, and hydrogen
What is responsible for the yellow-orange coloration of leaves in the fall ?
carotenoids
Which theory states that all living things are composed of cells?
cell theory
Plant cells, unlike animal cells, are characterized by the presence of a _____
cell wall and a central vacuole
Which of the following structures can perform all the activities required for life?
cells
Which of the following is hydrophilic?
cellulose
In plant cells, _____ may contain organic nutrients, pigments, and poisons.
central vacuoles
Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing _____
chemical energy into kinetic energy
What compound is found at the reaction center of a photosystem?
chlorophyll a
Which organelle is responsible for photosynthesis?
chloroplast
The structural combination of DNA and protein forms
chromatin
The figure below shows a paramecium, a single-celled freshwater protist. The hairline structures visible on the paramecium allow it to move. These structures are
cilia
Which part of cellular respiration produces the most NADH ?
citric acid cycle
!What advantage do C-4 plants have in hot weather? Is this adaptation spatial or temporal?
close their stomata to save water during hot and dry weather
The tendency of molecules of the same kind to stick together is called _____
cohesion
The principle that energy cannot be created or destroyed is known as _____
conservation of energy
Humans are _____
consumers
Which of the following is a result of glycolysis?
conversion of glucose to pyruvic acid
The hydrogens and oxygen of a water molecule are held together by ______ bonds.
covalent
What name is given to bonds that involve the sharing of electrons ?
covalent
The ability to tolerate lactose throughout life is most likely to be seen in ______.
cultures that keep dairy herds
In eukaryotic cells, what name is given to the region between the nucleus and the plasma membrane
cytoplasm
Where in the cell does glycolysis occur?
cytoplasm
If you provided your shade-tolerant plants with their preferred wavelength of light, but only minimal amounts of water, which of the following would you expect to occur?
decreased amounts of ATP being produced by the plants
Which of the following is NOT a potential impact of ocean acidification ?
decreasing H+ concentration
Enzymes increase the rate of a reaction by _____
decreasing activation energy
What name is given to the following reaction? galactose + glucose → lactose + water
dehydration reaction
What name is given to the following reaction? glycerol + 3 fatty acids → triglyceride + 3 water molecules
dehydration reaction
Destruction of a protein's shape is called _____
denaturation
If a cell's lysosomes burst, the cell would _____
digest itself
Lysosomes are responsible for
digestion of organic matter inside the cell
Complete the equation: monosaccharide + monosaccharide → ______ + water
disaccharide
In the following equation, lactose is a ______. galactose + glucose → lactose + water
disaccharide
When a base is added to a buffered solution, the buffer will _____
donate H+ ions
Adjacent water molecules are connected by the ______.
electrical attraction between the hydrogen of one water molecule and the oxygen of another water molecule
Which of the following is found in both cellular respiration and in the light reactions of photosynthesis?
electron transport chain
During redox reactions, _____
electrons are lost from one substance and added to another substance
Which of the following is NOT recycled but is lost from ecosystems?
energy
Which of the following is a measure of randomness in a system?
entropy
Substances that plug up an enzyme's active site are _____.
enzyme inhibitors
What molecules are scientists currently trying to use to power nanotechnology devices, such as microscopic robots?
enzymes
_____ is a steroid.
estrogen
What waste product do yeast produce under anaerobic conditions?
ethyl alcohol
Humans are composed of _____ cells.
eukaryotic
Differentiate between a prokaryotic and eukaryotic cell
eukaryotic cells are more complex; they have organelles and a nucleus. ; the presence of a nucleus, the size and complexity of the ribosomes, how the cells reproduce and the presence of a cell wall.
Sweating cools your body by
evaporative cooling
The branch of biology that explains both the diversity and the unity of life is
evolution
When a molecule absorbs a photon, one of its electrons is raised to the _____ state
excited
When two solutions that differ in solute concentration are placed on either side of a selectively permeable membrane, and osmosis is allowed to take place, the water will _____.
exhibit a net movement to the side with lower water concentration
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. Which of the following processes could be responsible for its secretion?
exocytosis
When a person cries, tears are exported from cells through the process of _____
exocytosis
Examine the cells below. Cells with a higher concentration of ions than the surrounding medium tend to _____
expand
A glycerol with three fatty acids attached is referred to as a _____
fat
Cellulose is an example of _____
fiber
Know the maximum number of electrons that may occupy an elements first and second shells.
first shell: 2 second shell: 8
A newly discovered multicellular organism obtains food by digesting dead organisms. Such an organism is most likely a member of the kingdom _____
fungi
What is the function of stomata?
gas exchange
A specific stretch of DNA that programs the amino acid sequence of a polypeptide is a _____
gene
ATP synthase plays a role in _____
generating ATP
_____ store the information necessary to produce proteins.
genes
Which of these equations describes aerobic cellular respiration?
glucose + oxygen → carbon dioxide + water + energy
Which of the following are isomers?
glucose and fructose
Animals store carbohydrates as _____
glycogen
Which of the following metabolic pathways is common to both aerobic and anaerobic processes of sugar breakdown ?
glycolysis
Which of the following metabolic pathways is common to both aerobic and anaerobic processes of sugar breakdown?
glycolysis
Which of these stages occur(s) in the cytoplasm?
glycolysis
Which of these stages of cell respiration can occur without the others ?
glycolysis
Which of the following is the correct sequence of stages in cellular respiration?
glycolysis, citric acid cycle, electron transport
The shorter the wavelength of visible light, the _____
greater the energy
The energy of wavelengths that appear _____is LEAST useful to photosynthesis.
green
Plant cells _____
have chloroplasts and mitochondria
When mixed with water, phospholipids spontaneously form membranes because they _____.
have hydrophilic phosphate groups that are attracted to water and hydrophobic fatty acids tails that avoid water
One difference between eukaryotic and prokaryotic cells is that eukaryotic cells _____ prokaryotic cells.
have membrane-enclosed structures called organelles, which are lacking in
Explain what Darwin meant when he described evolution as "descent with modification"
he meant that only the desirable and strong traits would pass along. ; captured the duality of life's i. unity (descent) and ii. diversity (modification).
Humans are both _____
heterotrophs and consumers
The following molecule is best described as a _____ CH3—CH2—CH2—CH2
hydrocarbon
Adjacent water molecules are joined by _____ bonds.
hydrogen
Saturated fats are saturated with ______.
hydrogen
Explain how hydrogen bonds are different from ionic and covalent bonds.
hydrogen bonds are weaker than ionic and covalent bonds
What is the name given to the reaction that breaks peptide bonds ?
hydrolysis
What name is given to the following reaction? sucrose + water → glucose + fructose
hydrolysis
You try to start your car, but it does not start. Which of these is a prediction ?
if I recharge the battery, then my car will start
A protists that contains contractile vacuoles most likely lives _____
in fresh water
The light reactions of photosynthesis take place _____
in the thylakoid membrane
Which of these is NOT considered an advantage of biofuels from food crops ?
increased crop prices
Which of the following is a health effect of a diet high in saturated fats?
increased risk of heart attack
More than half of all known species are _____ ?
insects
Lactic acid build up in muscles is a sign that _____
insufficient oxygen is reaching the muscles
Which of the following elements, essential to life, is a trace element?
iodine
An atom with an electrical charge is a(n)
ion
In the following reaction, what type of bond is holding the two atoms together? K + Cl → K+ + Cl- → KCl
ionic
The bond between oppositely charged ions is a(n) _____ bond.
ionic
Differentiate between ionic and covalent bonding.
ionic bonds are attractions between opposite charges. They are stronger. ; covalent bonds share electrons (when two atoms share one or more pairs of outer-shell electrons)
Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of the organelles tells you that the environment _____
is hypotonic to the protozoan
A cell that neither gains nor loses a net amount of water at equilibrium when it is immersed in a solution is _____.
isotonic to its environment
Explain why ice floats on water.
it is less denser than liquid water
You are riding on your bike and stop pedaling, coasting along the road. Eventually, your bike slows down and stops, What happened to the energy of your motion when your bike stopped?
it was released as heat.
As water freezes, _____
its molecules move farther apart
Which one of the following is most similar to the mechanism of an enzyme inhibitor?
keeping someone from parking by parking in their designated spot
C4 plants conserve water by _____
keeping their stomata closed when the weather is hot and dry
An object at rest has no _____ energy, but it may have _____ energy resulting from its location or structure.
kinetic...potential
People with lactose intolerance do not have enough _____
lactase
Relative to prokaryotic cells, eukaryotic cells are usually _____
larger and more complex
Plant cells that contain the organelle responsible for photosynthesis are concentrated in cells of the _____
leaves
Which of the techniques reveal internal cellular detail?
light micrograph and transmission electron micrograph
Functions of the smooth endoplasmic reticulum include
lipid synthesis, steroid synthesis, and drug detoxification
People have long speculated about whether life exists on Mars. Scientists have evidence that on Mars, _____
liquid water has existed in the past
Based on its function in detoxifying drugs, you would expect to find a large amount of smooth ER in _____ cells.
liver
Tay-Sachs disease results from _____ lacking a specific type of lipid-digesting enzyme.
lysosomes
Information is transferred from the nucleus to ribosomes via _____
mRNA
A difference between marathon runners and sprinters is _____
marathon runners have more slow-twitch fibers in their leg muscles
Vacuoles are _____
membranous sacs
The sum total of all the chemical reactions that occur in organisms is called _____
metabolism
During a race such as a marathon, the skeletal muscle cells in your legs use a lot of energy to continually contract and power your muscles. What organelle is most likely abundant in skeletal muscle cells?
mitochondria
Electron transport takes place in the _____
mitochondria
In the following reaction, galactose is a _____ galactose + glucose → lactose + water
monomer
The lower the pH of a solution, the _____
more acidic the solution
In order to have a positive charge, an atom must have _____
more protons than electrons
A fat that is hydrogenated is _____
more solid
Taxonomy is the _____.
naming and classifying of species
Which of these is most closely associated with Darwin?
natural selection
Differentiate between natural and artificial selection
natural selection is by chance while in artificial selection the genes are chosen. ; Artificial selection is the selective breeding of domesticated plants and animals by humans In artificial selection, humans do the selecting instead of the environment. It is this unequal reproductive success that Darwin called natural selection. The product of natural selection is adaptation.
Describe the structure of the atom, including all subatomic particles, their sizes, charges, and location in the atom.
neutrons (neutral charge; located in nucleus) protons (positive charge; located in nucleus) electrons (negative charge; located outside nucleus)
An atom's _____ are found in its nucleus
neutrons and protons
Which of the following structures manufactures the components of ribosomes?
nucleolus
Nucleic acids are polymers of _____ monomers.
nucleotide
The DNA of a eukaryotic cell is found within the _____
nucleus
What are the two main processes upon which ecosystems depend?
nutrient recycling and energy flow
Which of the following is a producer ?
oak tree
Discovery science is primarily based on _____
observation
List and define/describe/ explain each of the steps in the Scientific Method
observation question hypothesis prediction experiment
Which of the following are the proper components of the scientific method?
observation, question, hypothesis, prediction, experiment, results, conclusion
Oleic acid is a fatty acid that occurs naturally in many animal and vegetable fats and oils. What can you tell about oleic acid just by looking at its structure?
oleic acid is an unsaturated fatty acid
Where does protein synthesis take place?
on ribosomes
CAM plants conserve water by _____
opening their stomata only at night
What name is given to the functional compartments of a cell?
organelles
The figure below shows that _____
our cells can use sugars, fatty acids, and amino acids to produce ATP
Identify which form of NADH/NAD+ is the reduced form and which is the oxidized form.
oxidized = NAD+ reduced form = NADH
A process is referred to as aerobic if it requires _____
oxygen
An aerobic process requires ______
oxygen
The final electron acceptor of aerobic respiration is _____
oxygen
Examine the figure below. Which of the following reactant(s) primarily come(s) from the air?
oxygen and carbon dioxide
During cellular respiration, electrons move through a series of electron acceptor molecules. Which of the following is a TRUE statement about this process ?
oxygen is eventually reduced by the electrons to form water
Diffusion is an example of _____
passive transport
The act of a white blood cell engulfing a bacterium is ______.
phagocytosis
Energy is transferred from ATP to other molecules by transferring a(n)
phosphate group
_____ are the major lipids of plasma membranes.
phospholipids
The concept of a membrane as a fluid mosaic reflects the ability of _____
phospholipids and most proteins to drift about in the plane of the membrane
What name is given to a discrete packet of light?
photon
Which of the following is a feature of prokaryotic cells but not eukaryotic cells?
pili
Which of the following is an autotroph?
pine tree
Predict what types of compounds can be dissolved in water.
polar substances - ionic and polar covalent compounds
For good health, it is important to include _____ in our diets
polysaccharides
In the process of evolution by natural selection illustrated in the accompanying figure, which of the following is the mechanism or agent of natural selection?
population with varied inherited traits. ->elimination of individuals with certain traits ->reproduction of survivors ->? Reproductive success
A rock on the top of a mountain contains _____ energy.
potential
Diffusion _____
proceeds until equilibrium is reached
Human muscle cells use lactic acid fermentation to _____
produce ATP without O2
Members of the kingdom Plantae differ from members of the other kingdoms of Eukarya in that most members of the kingdom Plantae _____
produce their own food
Photosynthetic organisms are _____
producers that make all their own organic matter from inorganic molecules
Describe the roles of producers, consumers and decomposers within an ecosystem
producers: make their own food consumers: feed off producers decomposer: break down nutrients Producers change energy into matter with chemical energy that other organisms can use and then consumers pass the matter and energy on to other organisms by eating and being eaten; decomposers recycle some of the energy and the matter back into the system.
Respiration describes the exchange of gases between your blood and the air. Cellular respiration _____
produces ATP
When using a microscope to view cells you obtain from scraping under your fingernails, you notice that the cells lack nuclei, there fore you conclude that the cells must be a type of _____ cell.
prokaryotic
The extracellular matrix of animal cells _____
protect and support cells
!Describe the structure of the plasma membrane, including an explanation of why we describe it as a phospholipid bilayer and a fluid mosaic.
protein in the center. in between phospholipids. cytoplasm is also present in the cell.
Which of the following is a function of the Golgi apparatus?
protein modification
Enzymes are _____
proteins
Identify what class of molecules make up the electron transport chain.
proteins
All atoms of an element have the same number of ______.
protons
Isotopes of an element have the same number of _____ and different numbers of _____
protons... neutrons
Given an atomic symbol, determine how many protons, neutrons and electrons the element contains.
protons= atomic number so all we need to do is look at the periodic table the number of neutrons and electrons ALMOST always is the same as the number of protons
Over a span of two decades, scientists measured changes in the beak size of a population of Galápagos ground finches. This _____
provided evidence of natural selection in action
A product of glycolysis is _____
pyruvic acid
How do radioactive isotopes differ from isotopes ?
radioactive isotopes are unstable, isotopes are stable
List the reactants and products in photosynthesis.
reactants: carbon dioxide and water products: glucose and oxygen
The last stage of one complete turn of the Calvin cycle involves
regeneration of RuBP
Which of the following is a function of the plasma membrane?
regulate the traffic of chemicals in and out of the cell
A base _____
removes H+ ions from a solution
Anything that prevents ATP formation will most likely _____
reslt in cell death
Through what structure(s) do plants obtain most of their water?
roots
What type of microscope would be best for studying the detailed structure of the surface of a plasma membrane?
scanning electron microscope
Which of these statements is correct ?
scientific ideas are subject to repeated testing
A pleated sheet is an example of protein _____ structure.
secondary
? reproductive success
selective predation
In a scientific experiment, the control group _____.
serves as a basis of comparison with the experimental group
A protein's function is most dependent on its _____
shape
Relaying a message from a receptor protein to a molecule that performs a specific function within a cell is called _____
signal transduction
How many times must the Calvin cycle turn for the plant cell to be able to produce one molecule of glucose?
six
List the three physical states of matter.
solid, liquid, gas
Sugar dissolves when stirred into water. The sugar is the _____ the water is the _____ and the sweetened water is the _____
solute, solvent, solution
All of the representations in the following figure except one clearly shows double bonds. Choose the exception
space-filling model
What are grana?
stacks of membranous sacs
Which of the following is an example of a polysaccharide?
starch
Plants use photosynthesis to
store chemical energy, and they use cellular respiration to harvest energy.
Cellular respiration can be described as the conversion of the energy _____
stored in food molecules to energy stored in ATP
Which component of the following reaction is the enzyme? sucrose + sucrase + water → sucrase + glucose + fructose
sucrase
Which component of the following reaction is the substrate? sucrose + sucrase + water → sucrase + glucose + fructose
sucrose
Table sugar is ______.
sucrose, a monosaccharide
Similar to the nucleus, chloroplasts and mitochondria are _____
surrounded by two membranes
Photosynthesis contributes to plant growth by _____
taking in carbon dioxide and making sugars (carbohydrates)
A hypothesis is a(n)
tentative answer to a question
What does "adaptation" mean in an evolutionary context ?
the accumulation of favorable variations in a population over time
What does adaptation mean in a biological context?
the accumulation of favorable variations in a population over time
What is energy?
the capacity to cause change
The second stage in aerobic respiration is _____
the citric acid cycle
Which of the following is an adaptation to increase in the surface area of a part of a cell that is involved in cellular respiration ?
the cristae of a mitochondrion
Osmosis can be defined as _____
the diffusion of water across a selectively permeable membrane
Examine the drawing of an atom below. The art is technically INCORRECT in that _____
the electrons should be much farther away from the nucleus
?Examine the drawing of an atom below. The art is technically INCORRECT in that
the electrons should be much farther away from the nucleus.
Examine the structures of the plant and animal cells below. Which of the following organelles connect(s) to the nuclear envelope?
the endoplasmic reticulum
Refer to the accompanying figure. Which of the following is TRUE regarding the behavior of a chlorophyll molecule as it absorbs a photon ?
the energy of a photon raises an electron to the excited state
Which of the following parts of a cell is (are) most like the shipping center of a company?
the golgi apparatus
Science is _____
the inquiry-based effort to describe and explain nature
Some friends are trying to make wine in their basement. They've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. After several days, they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. The most likely explanation is that _____
the mixture needs less oxygen; yeast only produce alcohol in the absence of oxygen
In cellular respiration, most ATP is produced directly as a result of _____
the movement of hydrogen ions across the inner mitochondrial membrane
A child is born with a rare disease in which mitochondria are missing from certain skeletal muscle cells. Physicians find that the muscle cells function. Not surprisingly, they also find that _____
the muscles contain large amounts of lactic acid following even mild physical exercise
Use the periodic table to determine how many valence electrons an atom of a given element contains and to determine how many covalent bonds it can make.
the number of valence electrons is equal to the atom's main group number. The number of covalent bonds formed is equal to the number of valence electrons minus the number of unshared electrons of an atom
Identify the oxidized and reduced forms of NADPH.
the oxidized form is NADP+, while the reduced form is NADPH
Polar molecules are hydrophilic (water loving) and will readily dissolve in aqueous (water based) solutions. Nonpolar molecules are hydrophobic (water fearing) and will not dissolve in water. Phospholipids are described as amphipathic molecules, meaning they have both a significant polar region and a significant nonpolar region. Explain how this property (being amphipathic) affects the behavior of phospholipids when placed in water.
the phospholipids' hydrophilic ("water- loving") heads are arranged to face outward, exposed to the aqueous solutions on both sides of a membrane. Their hydrophobic ("water-fearing") tails are arranged inward, mingling with each other and shielded from water.
Antibiotic resistance evolves in bacteria when _____
the presence of antibiotics favors bacteria that already have genes for resistance
If the interior of the thylakoid were not a sealed compartment _____
the proton gradient could not be maintained
Examine the following figure. Imagine that cell signaling using a signal transduction pathway is like a person answering the door after hearing the doorbell ring. Which structure in this figure is like the button for the doorbell?
the receptor protein
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?
the relative inelasticity and strength of the plant cell wall
What is biology
the scientific study of life
The ultimate source of the energy in food is _____
the sun
What does the figure below show?
the synthesis of ATP through the addition of a phosphate group
A balloon permeable to water but not to glucose contains a 10% glucose solution. A beaker contains a 5% glucose solution. What will happen when the balloon is submerged in the beaker?
the volume of water in the beaker will decrease
The color that we see when looking at a pigmented object is _____
the wavelengths that are reflected or transmitted by the pigmented object
Explain how monomers form polymers and how polymers are disassembled into monomers, including a discussion of what types of chemical reactions are involved.
they form covalent bonds and release water molecules as a byproduct, hydrolisis uses water to cause the polymers bonds to break and become monomers
In the accompanying figure, the molecule that makes up the bulk of the mass of the plant comes in mostly _____
through the transparent covering of the leaf into the photosynthetic cells
In photosynthesis, an H+ ion gradient forms across the _____
thylakoid membrane
Where are photosystems located?
thylakoid membrane
What name is given to the membranous sacs found within a chloroplast?
thylakoids
Within the inner membrane of a chloroplast, interconnected sacs of membrane called _____ are suspended in a thick fluid called the _____
thylakoids...stroma
What is one reason why plants have accessory pigment molecules, like chlorophyll b and carotenoids?
to absorb energy in parts of the electromagnetic spectrum that chlorophyll a cannot
Facilitated diffusion across a biological membrane requires ______ and moves a substance ______ its concentration gradient.
transport proteins... down
What structures move proteins from the ER to the Golgi apparatus?
transport vesicles
By definition, what type of fatty acid has double bonds ?
unsaturated
Which of the following best describes the direct mechanism of ATP production during photosynthesis?
use of the energy stored in hydrogen ion (H+) gradients; the potential energy of the proton gradient is released as the protons move down their gradient through special membrane protein channels; this energy is converted to chemical bond energy in the ATP molecule
Photosynthetic organisms like grass are able to _____
use substances in the air as a major source of carbon.
The waste products of cellular respiration include _____
water and carbon dioxide
_____ is a hydroxyl group.
—OH
Interpret pH values and determine how much more or less acidic a substance with one pH value is than another substance with a different pH value.
1-6 is acid 7 is neutral 8+ is base
List and describe the 4 levels of protein structure, including what important interactions act to stabilize or reinforce each level of structure.
1. Primary - describes the unique order in which the amino acids are linked together, 2. Secondary - refers to the coiling or folding of a polypeptide chain that gives the protein it's 3D shape 3. tertiary - the comprehensive 3D structure of the polypeptide chain of a protein 4. quaternary - the structure of a protein macromolecule formed by interactions between multiple polypeptide chains.
List the three main steps involved in a signal transduction pathway (cell signaling)
1. Reception: A cell detects a signaling molecule from the outside of the cell. 2. Transduction: When the signaling molecule binds the receptor it changes the receptor protein in some way. This initiates the process of transduction. Each relay molecule in the signal transduction pathway changes the next molecule in the pathway. 3. Response: Finally, the signal triggers a specific cellular response.
List the six primary functions of membrane proteins.
1. Transport - movement of chemicals through a channel 2. Enzymatic activity - A protein built into the membrane with active site exposed. 3. cell signaling - a change in the protein that relays the message to the inside of the cell. 4. cell cell recognition - Some proteins with chains of sugars serve as identification tags recognized by other cells. 5. intercellular joining - proteins may link adjacent cells. 6. Attachment to the cytoskeleton and extracellular matrix - proteins help maintain cell shape and coordinate changes
Recognize examples of potential energy and kinetic energy.
1. holding a stretched spring (potential energy) and then releasing it (kinetic energy) 2. holding a box above the ground (potential energy) and then dropping it (kinetic energy
List and describe the ten levels in the hierarchy of life
1. molecules and atoms, 2. organelles - functional components of a cell 3. cells, 4. tissues - collection of cells, 5. organs/organ system - collection of tissue & organisms 6. organisms- individual living thing carrying their own functions, 7. population - communities within a group 8. community, 9. ecosystem - all organisms in an area 10. biosphere - all existing life
List and describe the seven properties and processes associated with life
1. order- complex organization 2. regulation - organisms can regulate their internal temperatures 3. growth and development - DNA controls the pattern of growth & development from baby to adult 4. energy processing - organisms take in energy, process it to perform activities, then emit it as heat 5. response to the environment - organisms respond to changes in environmental conditions and stimuli 6. reproduction - organisms can reproduce their own kind 7. evolution - each generation provides the possibility for change within the population over time
Explain the two observations which led to Darwin's theory of natural selection and explain what is meant by differential (unequal) reproductive success
1. overproduction and competition 2. individual variation Unequal reproductive success - heritable traits best suited to the local environment are more likely to survive and reproduce.
Identify in what part of the cell each of the three stages of cellular respiration take place.
1.glycolysis - in the cytoplasm 2. citric acid- mitochondria 3. electron transport- mitochondria
Ten kilocalories are equivalent to _____ calories
10,000
Relative to a pH of 6, a pH of 4 has a _____
100 times higher H+ concentration
In aerobic respiration, how many molecules of acetic acid are produced from six molecules of glucose?
12
Anaerobic respiration produces a maximum of _____ ATP per glucose.
2
Sulfur has an atomic number of 16. How many covalent bonds can sulfur form?
2
Large amounts of oxygen gas first appeared in Earth's atmosphere about _____ years ago.
2.7 billion
You have a 2-kg bottle of liquid water at 0°C. About how many Calories are needed to heat up the water to 100°C?
200 calories
How many oxygen atoms are in the products of the following reaction? C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O
24
The human genome consists of about _____ chemical letters
3 billion
Humans convert approximately _____ of the energy stored in food to useful work.
34%
Aerobic cellular respiration generates about _____ ATP from one glucose.
38
A single carbon atom can form a maximum of _____ covalent bond(s).
4
Most human cells contain _____ chromosomes
46
Beryllium's atomic mass is 9, and its atomic number is 4. How many neutrons are found in a beryllium atom?
5
Nitrogen has an atomic number of 7 therefore, it has ______ electrons in its outermost electron shell.
5
Which of the following equations best summarizes photosynthesis?
6 CO2 + 6 H2O ? C6H12O6 + 6 O2
The graph below shows data regarding radioactive decay if carbon-14. If decay continues to occur normally, how much C-14 will remain after 22,800 years ?
6.25%
Human body cells are approximately _____ water
70-95%
On a lab bench, there are four balloons filled with identical volumes of different salt solutions: 0% (balloon A), 5% (balloon B), 10% (balloon C), and 15% (balloon D). There are also four beakers each filled with identical volumes of a 10% salt solution. The balloons are semi-permeable, that is, only water can enter and exit the balloon. All four balloons are placed in separate beakers at the same time and are allowed to come to equilibrium. Which is the correct order of balloon volumes at equilibrium, from largest to smallest?
A < B < C < D
Describe the generalized structure and function of a photosystem.
A photosystem is a cluster of a few hundred pigment molecules that function as a light-gathering antenna, they are molecules that focus light energy onto a reaction center.
Explain the difference between the use of the word "theory" in everyday language and the correct, scientific use of the word. Include a discussion of how a hypothesis and a theory are related
A scientific theory is much broader in scope than a hypothesis. In everyday language, a theory means a hunch or speculation. In science, the word theory refers to a comprehensive explanation of an important feature of nature supported by facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena".
Recognize the structure of triglycerides and the characteristic four fused ring structure of steroids.
A typical fat, or triglyceride, consists of 1. a glycerol molecule, 2. joined with three fatty acid molecules, 3. via a dehydration reaction.
An uncharged atom of gold has an atomic number of 79 and an atomic mass of 197. This atom has ______ protons, ______ neutrons, and ______ electrons.
A) 79... 118... 79
A DNA molecule has the sequence AGTTCAACT. The equivalent RNA molecule would have the sequence _____
AGUUCAACU
What compound directly provides energy for cellular work?
ATP
The products of the light reactions of photosynthesis are _____
ATP and NADPH
The figure below shows that _____
ATP can perform cellular work when it releases a phosphate group
Explain how ATP provides energy for cellular work.
ATP energizes other molecules in cells by transfer- ring phosphate groups to those molecules. (ADP) When a target molecule accepts the third phosphate group, it becomes energized and can then perform work in the cell.
The Calvin cycle requires ______ and ______ from the light reactions in order to operate.
ATP... NADPH
Describe all the different molecules that can be metabolized via aerobic cellular respiration and indicate where each type of molecule enters the pathway.
After functioning anaerobically for about 15 seconds, muscle cells begin to generate ATP by the process of fermentation
Explain how changes in energy and/or transfers of energy affect entropy.
All energy conversions increase the entropy of the universe
Recognize the general structure of an amino acid.
Amine group + carboxyl group + R side chain
Which one of the following is true?
An enzyme's function depends on its three-dimensional shape.
Several students were talking about which came first in the history of the Earth. Which student has the best understanding of what happened?
Anaerobic organisms must have come first because there was no oxygen in the atmosphere.
How can radiation be controlled and safely used in medicine?
Apply radiation to specific parts of the body at controlled doses
Which domain(s) consist(s) of prokaryotic cells?
Bacteria and Archaea
Describe the steps in Alcoholic Fermentation, including input, output, and any other molecules produced. How are Lactic Acid and Alcoholic Fermentation similar and how are they different?
Both are anaerobic processes that break down glucose to make ATP and recycle NAD+ to glycolysis. Lactic acid fermentation produces lactic acid, alcoholic fermentation produces alcohol and carbon dioxide.
Which two eukaryotic organelles contain their own DNA?
Both mitochondria and chloroplasts contain their own DNA and ribosomes.
Compare and contrast C-3, C-4 and CAM plant photosynthetic pathways.
C3 plants a. use CO2 directly from the air and b. are very common and widely distributed. C4 plants a. close their stomata to save water during hot and dry weather and b. can still carry out photosynthesis. CAM plants a. are adapted to very dry climates and b. open their stomata only at night to conserve water.
What are the reactant(s) in the following chemical reaction? C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O
C6H12O6, H2O, and O2
The Calvin cycle makes direct use of _____ to make _____.
CO2, ATP, and NADPH...sugar
The first step of the Calvin cycling is the incorporation of _____ into _____
CO2... RuBP
List and describe the nutritional importance of carbohydrates, lipids and proteins.
Carbohydrates - energy and are found in foods, make glucose, which is your body's main energy source. Glucose can be used right away for energy or stored away to be used later. Lipids - provide a source and store of energy. (chemical messengers) and bile acids (digestive juices) are made. Protein - make enzymes, hormones, and other body chemicals. Protein is an important building block of bones, muscles, cartilage, skin, and blood. They are all "macronutrients," meaning that the body needs relatively large amounts of it.
______ is an example of an element.
Carbon
Predict approximately how many molecules of ATP are produced for every one molecule of glucose that undergoes aerobic cellular respiration.
Cellular respiration can produce up to 32 ATP molecules for each glucose molecule consumed
Explain how breathing is related to cellular respiration.
Cellular respiration requires a cell to exchange gases with its surroundings. i. Cells take in oxygen gas. ii. Cells release waste carbon dioxide gas. Breathing exchanges these same gases between the blood and outside air.
Describe the ATP cycle.
Cellular work spends ATP, which is recycled when ADP and phosphate are combined using energy released by cellu- lar respiration
List the different types of pigments found in chloroplasts and describe the role played by each type of pigment.
Chlorophyll a i. absorbs mainly blue-violet and red light and ii. participates directly in the light reactions. Chlorophyll b i. absorbs mainly blue and orange light and ii. participates indirectly in the light reactions.
Identify the plant organ where the majority of photosynthesis takes place and explain why this is the major location of photosynthesis in plants.
Chloroplasts are: a. the site of photosynthesis and b. found mostly in the interior cells of leaves.
What are eukaryotic genes composed of ?
DNA
How does DNA direct protein production?
DNA programs protein production in the cytoplasm by transferring its coded information into messenger RNA (mRNA)
Explain the implications of global deforestation.
Deforestation removes a lot of photosynthetic plant life, thereby reduces the ability of the biosphere to absorb carbon.
Why do some plant species require shaded conditions while other plant species require bright sunlight?
Different species of plants have different pigment molecules that utilize different wavelengths of light.
What is the difference between discovery science and hypothesis-driven science ?
Discovery science is mostly about describing nature, whereas hypothesis-driven science tries to explain nature.
Information flow in biological systems is necessary for negative or regulative feedback to operate. Which of these examples does NOT involve flow of information providing feedback?
Drought kills many trees.
Describe the role of oxygen in cellular respiration.
During cellular respiration, hydrogen and its bonding electrons change partners from sugar to oxygen, forming water as a product
List the nitrogenous bases found in DNA and the nitrogenous bases found in RNA.
Each DNA nucleotide has one of four possible nitrogenous bases: 1. adenine (A), 2. guanine (G), 3. thymine (T), or 4. cytosine (C). The nitrogenous bases in RNA are the same, with one exception: instead of thymine, uracil (U) is used.
Recognize the abbreviated ring structure of glucose.
Each corner represents a carbon
List the three components of a nucleotide.
Each nucleotide has three parts: 1. a five-carbon sugar, 2. a phosphate group, and 3. a nitrogen-containing base.
Which one of the following is TRUE?
Enzymes catalyze specific reactions.
List the three Domains of life and identify what characteristics are unique to each domain
Eukarya: nucleus, organelles Bacteria: peptidoglycan (no nucleus,organelles, cicular chromosomes) Archaea : harsh environments, attachment (no nucleus,organelles, cicular chromosomes) They all have cells, DNA, RNA, membrane, ribosomes
Diagram the steps involved in the Calvin Cycle (light independent reactions), including inputs, outputs, and what is regenerated. How is the Calvin Cycle similar to the CAC in cellular respiration and how is it different?
Explanation of diagram: With the energy of ATP and the electrons from NADPH, the carbons from CO are used to make a three-carbon sugar called G3P. The remaining G3P sugars to regenerate RuBP. Both: biochemical pathways found in nature and cyclical processes that occur inside of cells. CAC produces ATP and carbon dioxide. Calvin Cycle uses them. CAC requires oxygen and occurs in mitochondria of all types of cells. Calvin Cycle happens only in photosynthetic plants and it does not need oxygen.
!Differentiate between a calorie and a "food calorie".
Food Calories (C) are actually kilocalories, are units used to measure the amount of energy in our foods and the amount of energy we expend in various activities.
One of the compounds that is a direct output of the Calvin cycle is _____
G3P
Describe the evolutionary basis of the role of glycolysis in both respiration and fermentation. What data support the theory that glycolysis evolved very early in evolutionary history.
Glycolysis could be used by ancient bacteria to make ATP a. when little oxygen was available, and b. before organelles evolved. Today, glycolysis: a. occurs in almost all organisms and b. is a metabolic heirloom of the first stage in the breakdown of organic molecules.
Summarize all reaction pathways of cellular respiration and account for all of the ATP produced. How much ATP is produced by each individual stage of respiration?
Glycolysis produces 2 ATP molecules, and the citric cycle produces 2 more. Electron transport begins with several molecules of NADH and FADH2 from the Citric Acid cycle(also known as Krebs cycle) and transfers their energy into as many as 34 more ATP molecules
The endomembrane system includes
Golgi apparatus, lysosomes, vacuoles, and endoplasmic reticulum
Explain which wavelengths of visible light are poorly absorbed by chloroplasts. Explain which wavelengths of visible light are mainly responsible for photosynthesis.
Green is poorly absorbed by chloroplasts. Chloroplasts absorbs light mainly in the blue-violet and red orange part of the spectrum and those wavelengths of lights are the ones mainly responsible for photosynthesis.
_____ is the source of the oxygen gas released by a photosystem.
H20
In photosynthesis, redox reactions ultimately transfer electrons from _____ to _____
H20...CO2
Which of the following is the source of electrons for the light reactions?
H2O
Which of the following is an acid?
HCl
Why would a poster of a sick child say "No Antibiotics Please"?
His illness is caused by a virus.
Examine the pH scale below. How does household bleach compare to household ammonia?
Household ammonia has 10 times higher H+ concentration than household bleach.
Which of these would be a valid scientific hypothesis ?
Human and bacteria share a common genetic code.
Predict how the pH of a solution will change upon addition of acid and upon addition of base.
If a base is added to an acidic solution, the solution becomes less acidic. If an acid is added to a basic solution, the solution becomes less basic
Diagram the process of glycolysis, including the energy investment and energy payoff phases, the starting material (input), the end product (output), how many molecules of output are produced per molecule of input, and how many and what kind of any other molecules are generated during the process.
In glycolysis, a team of enzymes splits glucose, eventually forming two molecules of pyruvic acid. After investing 2 ATP at the start, glycolysis generates 4 ATP directly. More energy will be harvested later from high-energy electrons used to form NADH and from the two molecules of pyruvic acid.
Identify which molecules are undergoing oxidation and which molecules are undergoing reduction during the three stages of cellular respiration.
In the first step, glycolysis, glucose breaks down. In the second, aerobic respiration breaks the remains of the glucose down further and oxygen is reduced, donating an electron to hydrogen to form water. The entire process of cellular respiration oxidizes glucose.
Explain how photosynthesis and cellular respiration are related. Identify which types of organisms perform both photosynthesis and respiration and which types of organisms perform only cellular respiration.
In the overall equation for photosynthesis, notice that the reactants of photosynthesis are the waste products of cellular respiration
Diagram the Citric Acid Cycle including input, all intermediary products, output and how much of everything is produced. How many "turns" of the CAC per molecule of glucose?
Input : acetic acid, ADP+P , 3 NAD+, FAD Output: 2 CO2, ATP, 3 NADH, FADH2 Turns: 2
Describe the structure and function of a chloroplast.
Inside chloroplasts are interconnected, membranous sacs called thylakoids, which are suspended in a thick fluid called stroma. Thylakoids are concentrated in stacks called grana. The green color of chloroplasts is from chlorophyll, a light-absorbing pigment that plays a central role in converting solar energy to chemical energy
Explain why oxygen is described as an "electron grabber".
It attracts electrons strongly. By pulling electrons down the transport chain from fuel molecules, oxygen functions some-what like gravity pulling objects downhill.
Explain how a light microscope works and identify the two most important factors in microscopy.
Light microscopes can be used to explore the structures and functions of cells. When scientists examine a specimen on a microscope slide, a. light passes through the specimen and b. lenses enlarge, or magnify, the image. Magnification is an increase in the object's image size compared to its actual size Resolving power is the ability of an optical instrument to show two objects as separate
Identify the location in the cell where the light reactions and the Calvin cycle take place.
Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH. The Calvin cycle, which takes place in the stroma(fluid in chloroplast), uses energy derived from these compounds to make GA3P from CO2
What benefit is derived from having lysosomes?
Lysosomes can also a. destroy harmful bacteria, b. break down damaged organelles, and c. sculpt tissues during embryonic development, helping to form structures such as fingers.
Describe how all the organelles of the endomembrane system are related.
Many membranous organelles forming the endomembrane system in a cell are interconnected either a. directly by their membranes or b. by transfer of membrane segments between them.
You try to start your car, but it does not start. Which of these is a HYPOTHESIS ?
My car's battery is dead.
The first electron acceptor of cellular respiration is _____
NAD+
If an herbicide blocked the Calvin cycle before the generation of glyceraldehyde 3-phosphate (G3P), which of the following statements would be TRUE?
No sugar would be made by the plant
The Calvin Cycle is sometimes called the "dark reactions" . Could it take place if a plant were grown in the dark continuously ?
No, because sunlight is needed to split water to provide NADH.
Which of the following is produced during the light reactions of photosynthesis?
O2
Which of the following statements is TRUE?
Oxidation is the loss of electrons; reduction is the gain of electrons.
List the reactants and products in aerobic cellular respiration.
Oxygen and glucose are both reactants in the process of cellular respiration. The main product of cellular respiration is ATP. also carbon dioxide and water.
!Explain the main difference between passive transport and active transport. What is/are the key differentiating factor(s)? What is the driving force in passive transport? How is this different from active transport?
Passive transport requires no energy, active transport does.
Explain how photosynthesis and cellular respiration are related.
Photosynthesis and cellular respiration are complementary biochemical reactions. Photosynthesis requires the products of respiration, while respiration requires the products of photosynthesis.
You find a cell of a type you have never seen before. The cell has both a nucleus and a cell wall. Therefore, you conclude that it is likely to be a(n) _____ cell.
Plant
Identify which types of organisms perform both photosynthesis and respiration and which types of organisms perform only cellular respiration.
Plant and animal cells perform cellular respiration. Animals perform only cellular respiration Plants perform a. photosynthesis and b. cellular respiration.
Which of the following is NOT a property of life ?
Populations of organisms rarely change over time
Describe the two major processes in an ecosystem and explain the role of organisms in these two processes
Processes: 1. recycling of chemical nutrients 2. flow of energy
Describe what features differentiate prokaryotic and eukaryotic cells (how are they different?).
Prokaryotic cells are a. usually smaller than eukaryotic cells and b. simpler in structure. Eukaryotes : a. Only eukaryotic cells have organelles, membrane-enclosed structures that perform specific functions.
Which kingdom of Eukarya consists primarily of unicellular organisms?
Protista
How does RNA differ from DNA?
RNA contains uracil, DNA contains thymine
Compare and contrast the similarities and differences in the structure and composition of DNA and RNA.
RNA, ribonucleic acid, is different from DNA a. RNA uses the sugar ribose and the base uracil (U) instead of thymine (T). b. RNA is usually single-stranded, but DNA usually exists as a double helix.
When distinguishes a free ribosome from a bound ribosome?
Ribosomes may assemble proteins while the ribosomes are a. suspended in the fluid of the cytoplasm or b. attached to the outside of the nucleus or an organelle called the endoplasmic reticulum.
Compare/ contrast a scanning electron microscope with a transmission electron microscope. Under what circumstances would one choose to use one over the other?
Scanning electron microscopes (SEMs) examine cell surfaces. Transmission electron microscopes (TEMs) are useful for studying the internal structure of a cell
Describe the structure and function of a gene.
Structurally, a gene is a long stretch of DNA. Functionally, a gene contains the information needed to produce a protein.
If one strand of a DNA double helix has the sequence AGTACTG, what will be the sequence of the other strand ?
TCATGAC
