Bio exam 1- LC questions At which level of interaction does life first appear?
Chemical equation for photosynthesis
6CO2 + 6H2O ------> C6H12O6 + 6O2
glucagon
A protein hormone secreted by pancreatic endocrine cells that raises blood glucose levels; an antagonistic hormone to insulin.
Golgi apparatus
A system of membranes that modifies and packages proteins for export by the cell
Which molecules are produced during the light reactions of photosynthesis?
ATP, NADPH, O2
Hydrophilic
Attracted to water
Which statement about cellular metabolism is false?
Cellular metabolism occurs in animal but not plant cells.
double blind trial
Neither the doctors or patient know if they are receiving a placebo or the actual drug
proteins
Nutrients the body uses to build and maintain its cells and tissues
Which statement about the properties of life is false?
Organisms have an unchanging, constant internal environment.
oxidative phosphorylation
The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.
nonpolar covalent bond
a covalent bond in which the electrons are shared equally by the two atoms
Glucose molecules are to starch as ________ are to proteins.
amino acids
monomers of proteins
amino acids
organic compounds
compounds that contain carbon and hydrogen
when a protein unravels or unfolds we call this..
denaturation
The function of cellular respiration is to __________.
extract usable energy from glucose- The most prevalent and efficient energy-yielding pathway is cellular respiration, in which oxygen is consumed as a reactant along with organic molecules as fuel (frequently glucose).
saturated fats
fats that are solid at room temperature
Pyruvate
forms at the end of glycolysis.
reduction
gain of electrons
In the equation for cellular respiration shown below, __________ is oxidized, and __________ is reduced.
glucose ... oxygen- In cellular respiration, electrons (and hydrogens) are removed from glucose and are ultimately transferred to oxygen.
Life is organized in a hierarchical fashion. Which sequence correctly lists that hierarchy from least inclusive to most inclusive?
molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem
monomers of DNA
nucleotides
A major type of lipid found in cell membranes is
phospholipids.
Nucleolus
produces ribosomes
The end products of the citric acid cycle include all of these compounds except
pyruvate.
Which option lists the sequence of events in the cell-signaling process in the correct order?
reception, signal transduction, response
Which of the following structure(s) is/are found in prokaryotic cells?
ribosomes- Both prokaryotic and eukaryotic cells do have ribosomes.
ADP
(Adenosine Diphosphate) The compound that remains when a phosphate group is removed from ATP, releasing energy
ATP
(adenosine triphosphate) main energy source that cells use for most of their work
quantitative vs qualitative data
-Quantitative- numerical -Qualitative- descriptive observations ex. colors
Many names for sugars end in the suffix
-ose.
5 themes of biology
1. Evolution 2. Information 3. Structure and function 4. Energy and matter 5. Interactions
why are plants important
1. basic unit of life 2. source of energy 3. complex organelles 4. serve as food 5. used as medicine 6. used for clothes/other material objects 7. air
During glycolysis, a molecule of glucose is partially oxidized. What is the net gain of ATP and NADH for each glucose molecule during this chemical pathway?
2 ATP and 2 NADH- The net gain at the end of glycolysis is 2 ATP and 2 NADH.
The energy production per each glucose molecule through the citric acid cycle is ________
2 ATP, 6 NADH, 2 FADH2- The NADH and FADH2 molecules then carry electrons to the electron transport chain for use in generating ATP.
In simple summary form, the Calvin cycle requires an input of __________ for every product that is formed and the output product is __________, which is used for glucose synthesis.
3 CO2; a three-carbon molecule- For every molecule of glyceraldehyde-3-phosphate (G3P) produced as an output, three CO2 molecules have entered the cycle and are each added to a molecule of RuBP from the previous turns of the cycle. After intermediate molecules are processed, one G3P leaves the cycle as an output. G3P molecules remaining in the cycle are rearranged to form RuBP.
Which of the following equations represents photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2- Photosynthesis requires carbon dioxide and water for the production of sugar and oxygen.
Oxidation
A chemical change in which a substance combines with oxygen, as when iron oxidizes, forming rust
dehydration reaction
A chemical reaction in which molecules combine by removing water
DNA
A complex molecule containing the genetic information that makes up the chromosomes.
unsaturated fats
A fat that is liquid at room temperature and found in vegetable oils, nuts, and seeds.
insulin
A hormone produced by the pancreas or taken as a medication by many diabetics
Cytoskeleton
A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement
experiment
A research method in which an investigator manipulates one or more factors to observe the effect on some behavior or mental process
electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
Hypothesis
A testable prediction, often implied by a theory
prokaryotic cell
A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.
What two molecules are produced by the light reactions and used to power the Calvin cycle?
ATP and NADPH
Which statement comparing photosynthesis and cellular respiration is false?
ATP is not produced during photosynthesis; it is produced only during cellular respiration.
Which of the following is an accurate comparison of active transport and facilitated diffusion?
Active transport moves solutes against their concentration gradient; facilitated diffusion moves substances down their concentration gradient- Active transport involves moving solutes against their concentration gradient. Facilitated diffusion moves solutes down their concentration gradient. Active transport requires the use of ATP, whereas facilitated diffusion does not.
Choose the best answer that describes typical human gonad development:
All embryos begin with undifferentiated gonads that could become testes or ovaries- Right, and depending on many different biological, genetic, and environmental factors, one's genotype (XY or XX) may not match what develops, since having testes, ovaries, or even both are possibilities.
Lactase deficiency is more common in Asian, Native American, Mediterranean and some African populations than it is among people with northern or western European ancestry. How would you explain why this is so?
Although most mammals, including humans, are not able to digest the milk sugar, lactose, after infancy, the ancestors of northern and western Europeans relied on dairy products as an important part of their food supply. When other food sources were in low supply, mutations that allowed the expression of the enzyme lactase to persist past childhood conveyed an advantage to adults who were able to include dairy products in their diet.- The ability of adults to digest lactose is a result of a mutation related to the production of the enzyme lactase. Lactose-tolerant adults continue to make lactase beyond infancy, while lactose-intolerant adults do not.
NADPH
An electron carrier involved in photosynthesis. Light drives electrons from chlorophyll to NADP+, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle.
What connects the two photosystems in the light reactions?
An electron transport chain- An electron transport chain connects the two photosystems in the light reactions.
controlled experiment
An experiment in which only one variable is manipulated at a time.
Lysosomes
An organelle containing digestive enzymes
peptide bonds
Bonds between amino acids
Why do both mitochondria and chloroplasts possess circular chromosomes?
Both mitochondria and chloroplasts descended from free-living prokaryotes engulfed and maintained by early eukaryotic cells- Endosymbiotic theory explains the basis for a variety of peculiar features shared between mitochondria, chloroplasts, and prokaryotes.
chemical equation for cellular respiration
C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP
What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle?
Carbon dioxide (CO2)- Carbon dioxide provides the carbon atoms that are incorporated into sugars in photosynthesis. This is why plants need to take in carbon dioxide.
_____ are found only in plant cells, but _____ are found in both plant and animal cells.
Central vacuoles; ribosomes- Central vacuoles are found only in plant cells. Ribosomes are found in both plant and animal cells.
electrical signals
Changes in the membrane potential of a cell
In which of the following organelles does photosynthesis take place?
Chloroplast- Chloroplasts use energy from light to transform carbon dioxide and water into sugar and oxygen.
citric acid cycle
Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.
Eukaryotic cells
Contain a nucleus and other organelles that are bound by membranes.
Photosynthesis
Conversion of light energy from the sun into chemical energy.
pyruvate oxidation
Conversion of pyruvate to acetyl CoA and CO2 that occurs in the mitochondrial matrix in the presence of O2.
Based on the work of Catherine Dulac, would you expect a female mouse exposed to testosterone blast at birth and exposed to estrogen as an adult to have feminine adult sexual behavior?
Correct, an example of hormone exposure (non-exposure) affecting sexual behavior.
Based on the work of Catherine Dulac, would you expect a male mouse exposed to a testosterone blast at birth and also exposed to testosterone as an adult to have masculine adult sexual behavior?
Correct, an example of hormone exposure (non-exposure) affecting sexual behavior.
activation energy
Energy needed to get a reaction started
Choose which of these were conclusions made by Dr. Melissa Hine's research?
Girls that were exposed to more testosterone in development had a reduced female identity. In girls who displayed more masculine tendencies, their mothers had higher levels of testosterone.Girls with higher levels of testosterone were just as likely to choose toys made for boys as a male control group.
After reading the paragraphs below, answer the questions that follow.Recent studies suggest that flame retardants, chemicals that are used to slow down burning, can mimic estrogen hormones found in the human body. Scientists investigating this phenomenon developed three-dimensional images to show how the chemical structure of certain flame retardants allows the retardants to bind to and inhibit an enzyme (estrogen sulfotransferase) that breaks down (metabolizes) estrogen.Suppose the scientists want to conduct a study of the effects of flame retardants on estrogen levels. In a hypothetical study, the scientists use frogs to test the effects of flame retardants because the frogs' skin is highly permeable and therefore allows for easy absorption of chemicals.The scientists collected 20 wild adult frogs and brought them to a laboratory. Ten of the frogs (group 1: five male and five female) were kept in tanks mimicking their natural environment. The other ten frogs (group 2: five male, five female) were kept in tanks like those of group 1 except they were introduced to low amounts of flame retardants in the shallow water in their tank. Estrogen levels were measured on the first day of the experiment and then every 4 days for 20 days-- Why is group 1 needed in this experiment?
Group 1 is the standard of comparison for the experimental group.
What provides electrons for the light reactions?
H2O
Which of the following statements about hormones and the endocrine system is true?
Hormones only affect specific cells having the appropriate receptors- Hormones convey information via the bloodstream to cells throughout the body. Cells are unresponsive to a particular signal if they lack the appropriate receptors.
experimental group
In an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.
control group
In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.
Your throat is dry, and you want the last cough drop in the box to last a long time in your mouth. What should you do?
Keep the cough drop whole. This maintains the largest surface-to-volume ratio and slows the dissolution of the cough drop.
Which plant cell organelle converts chemical fuel into packets of chemical energy that can power the cell?
Mitochondrion-In both plant and animal cells, it's the mitochondria that convert chemical fuel into packets of chemical energy that can power the cell.
Which of these is a scientific hypothesis?
My excessive urination may mean that I have high blood pressure- this is a testable hypothesis
In the absence of oxygen, cells need a way to regenerate which compound?
NAD+- The NAD+ needs to be regenerated, which is why pyruvate is converted to ethanol or lactic acid.
The end products of glycolysis include
NADH.
During fermentation, __________ that was produced during glycolysis is converted back to __________.
NADH; NAD+- NADH molecules produced during glycolysis are converted back to NAD+ during fermentation. This NAD+ can then be used again in a new round of glycolysis.
In fermentation, ________ is ________
NADH; oxidized
Oxygen is the final electron acceptor for cellular respiration. What is the final electron acceptor in the light reactions of photosynthesis?
NADP+- NADP+ is the final electron acceptor in the light reactions of photosynthesis and is reduced to NADPH.
The light reactions of photosynthesis generate high-energy electrons, which are ultimately transferred to __________. The light reactions also produce __________ and _______
NADP+; ATP; oxygen- The electrons are transferred to NADP+, forming NADPH. ATP is formed via photophosphorylation, and oxygen is produced when water molecules are split.
What transports electrons from the light reactions to the Calvin cycle?
NADPH- NADPH is an electron carrier that picks up electrons in the light reactions and releases them in the Calvin cycle.
emergent properties
New properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases.
nonpolar vs polar
O2- nonpolar CO2- nonpolar HCI- polar H2O- Polar
Local farmers think that a commonly used pesticide is responsible for the increase in appearance of frogs with an additional appendage. To test this hypothesis, frogs are injected with a small amount of pesticide dissolved in ethanol. The frogs are allowed to produce offspring to test the effect of the pesticide. Which of the following would be the best controlled experiment?
One group is injected with ethanol, one group is injected with pesticide dissolved in ethanol, and one group is inserted with a needle but not injected with anything-The two control groups allow you to test a single variable, the pesticide.
Which statement is true about typical human development:
Only males are exposed to a testosterone blast at birth.- Right, this would be "typical". This doesn't always happen during human development.
Mitochondria
Powerhouse of the cell, organelle that is the site of ATP (energy) production
cellular respiration
Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
Which of the following is a reason why most scientific inquiries fail to rigidly adhere to the sequence of steps typically termed "the scientific method"?
Several rounds of making observations and asking questions typically precede the development of the testable hypothesis- The process of science is both repetitive and nonlinear.
Monosaccharides
Single sugar molecules
Which statement about steroid hormones is true?
Steroid hormones bind to specific receptor proteins, and the hormone-receptor complex acts as a gene activator.
Which of the following is a function of the central vacuole?
Storing compounds produced by the cell-One of the functions of the central vacuole is to store compounds produced by the cell.
rough ER
That portion of the endoplasmic reticulum studded with ribosomes.
Antidiuretic hormone (ADH) targets kidney cells and blood vessels, whereas growth hormone (GH) targets many different kinds of cells throughout the body. Which of the following is the best explanation for this observation?
The GH receptor is expressed in many different cells, whereas the receptor for ADH is expressed primarily in kidney select blood vessel cells- A hormone can act at any cell that expresses a receptor for that specific hormone. Growth hormone receptors are expressed by many different cells in the body. Receptors for ADH are expressed primarily in kidney and blood vessel cells.
At which level of interaction does life first appear?
The cell- life emerges from the ordered interactions of the structure of the cell.
Which of the following describes the function of the chloroplast?
The chloroplast converts light energy to chemical energy-The chloroplast makes food for the plant cell by converting light energy to chemical energy.
Which statement regarding the endomembrane system is false?
The endomembrane system is a system of interrelated membranes that are all physically connected.
independent variable
The experimental factor that is manipulated; the variable whose effect is being studied.
What is the relationship between the Golgi apparatus and the plasma membrane?
The finished products of the Golgi apparatus may leave the cell through vesicles that fuse with the plasma membrane- Transport vesicles from the Golgi move to the plasma membrane for export. In some cases the finished products become part of the plasma membrane or part of another organelle.
quaternary structure
The fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits.
dependent variable
The outcome factor; the variable that may change in response to manipulations of the independent variable.
You have a cup of vegetable oil and a vial full of normal phospholipids. What would you predict would happen if you dropped the phospholipids into the cup of vegetable oil?
The phospholipids would form a sphere with the heads on the inside.
Lactose is a disaccharide (two monosaccharides joined together). To metabolize lactose, individuals require an enzyme known as lactase. What is true about this reaction?
The reaction hydrolyzes the sugar- Lactose is hydrolyzed, or spilt, into two monosaccharide subunits.
A mutation in the gene for hormone A causes it to be unable to bind to its receptor protein. What do you predict will likely happen?
The receptor protein will not be activated and therefore will not initiate a signal transduction pathway.
Watching salt crystals form as ocean water evaporates, a student says, "Look−−more and more crystals are appearing. The ocean water is alive!" Which statement is an accurate evaluation of the student's remark?
The student is incorrect because all of the crystals reproduce the same kind of crystals with no variation to provide adaptation, so the ocean water is not alive.
tertiary structure
The third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of the amino acids making up the chain.
What do the rough endoplasmic reticulum, Golgi apparatus, and lysosomes have in common?
They are all membranous organelles comprising the endomembrane system.- Each of these organelles is a member of the endomembrane system and is constructed of the same type of membrane.
In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
Water will leave the balloon.
carbon sink
a forest, ocean, or other natural environment viewed in terms of its ability to absorb carbon dioxide from the atmosphere.
A characteristic of every animal hormone is that the hormone _____.
acts as a regulatory message or signal between cells- Hormones are secreted into body fluids, usually blood, and communicate regulatory signals throughout the body.
Which process produces the most ATP per molecule of glucose oxidized
aerobic respiration
The membranous compartmentalization of a cell
allows different chemical conditions to be maintained in different parts of the cell.
How are these two amino acids attached?
amino group to carboxyl group
A target cell that is affected by a particular steroid hormone would be expected to have
an intracellular receptor protein that binds the hormone.
In eukaryotes, most of the high-energy electrons extracted from glucose by cellular respiration __________.
are used to reduce NAD+ to NADH, which then delivers them to the electron transport chain- Most of the high-energy electrons extracted from glucose are picked up by NAD+ and sent through the electron transport chain.
Carbohydrates are mainly used in our bodies _____.
as fuel- Simple sugar molecules are a major fuel for cellular work.
The Calvin cycle is a series of reactions that _____.
assemble sugar molecules by fixing carbon- The Calvin cycle uses carbon supplied by CO2 and the energy and high-energy electrons supplied by ATP and NADPH, respectively, to assemble sugar molecules.
random assignment
assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups
Controlled studies conducted by scientists at University of California-Berkeley and described in module 26.3 of your text have shown that __________.
atrazine-exposed male frogs have decreased fertility over the control group-
Why must some hormones bind to a membrane receptor on a target cell's surface in order to activate it?
because they cannot cross cell membranes
As a scientist employed by the FDA, you've been asked to sit on a panel to evaluate a pharmaceutical company's application for approval of a new weight loss drug called Fat Away. The company has submitted a report summarizing the results of their animal and human testing. In the report, it was noted that Fat Away works by affecting the electron transport chain. It decreases the synthesis of ATP by making the mitochondrial membrane permeable to H+, which allows H+ to leak from the intermembrane space to the mitochondrial matrix. This effect leads to weight loss.You predict that a side effect of Fat Away will be increased
body temperature.
In the Calvin cycle carbon dioxide provides __________, whereas ATP and NADPH provide __________ and __________, respectively.
carbon; energy; high-energy electrons- The carbon for the carbon cycle comes from CO2, while energy comes from ATP produced by photophosphorylation during the light reactions. NADPH carries high energy electrons from the light reactions to the Calvin cycle.
The recent National Health and Nutrition Examination Survey found a 275% greater risk of what disease for individuals who consumed more than 25% of their daily calories from added sugar
cardiovascular disease
NADP+
carrier molecule that transfers high-energy electrons from chlorophyll to other molecules
what is the smallest unit of life?
cell
The plasma membrane's function would include which of the following?
communication- The plasma membrane is an important structure for cell communication with the external environment.
The fluid mosaic model describes the plasma membrane as consisting of
diverse proteins embedded in a phospholipid bilayer.
During redox reactions,
electrons are lost from one substance and added to another substance
As a scientist employed by the FDA, you've been asked to sit on a panel to evaluate a pharmaceutical company's application for approval of a new weight loss drug called Fat Away. The company has submitted a report summarizing the results of their animal and human testing. In the report, it was noted that Fat Away works by affecting the electron transport chain. It decreases the synthesis of ATP by making the mitochondrial membrane permeable to H+, which allows H+ to leak from the intermembrane space to the mitochondrial matrix. This effect leads to weight loss.Fat Away prevents ATP from being made by
eliminating the H+ gradient that allows ATP synthase to work
The primary function of light absorption by photosystems I and II is to produce __________.
energized electrons- These energized electrons power the photosynthetic electron transport chain to generate ATP, and ultimately be transferred to NADP+ to make NADPH for use in the Calvin cycle.
kinetic energy
energy of motion
main function of fats
energy storage
Atrazine and BPA are called endocrine disruptors because they mimic the action of __________
estrogen- These chemicals mimic estrogen and controlled studies suggest that their presence in the environment correlates with the demasculinization of male frogs.
three categories of sex hormones
estrogens, progesterone, androgens
When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will
exhibit a net movement to the side with lower free water concentration
clinical trials
experiments that study the effectiveness of medical treatments on actual patients
Researchers set up a study to determine whether large doses of a nutritional supplement would shorten the length of time it takes to recover from a cold. Three thousand volunteers were split into two groups. For two weeks, members of group A took 3,000 mg of the supplement daily. Group B received 3,000 mg of a placebo (sugar pill). At the end of the two-week period, the researchers inserted live cold viruses directly into the noses of all the volunteers. The volunteers in both group A and group B continued to take their daily pills. All the volunteers got colds, and there was no significant difference in the length of time the colds lasted.
group A only
Androgens stimulate
growth of facial hair in humans.
In the process of osmosis, water displays a net movement from an area of __________ water concentration to an area of __________ water concentration.
higher ... lower- Water displays a net movement down its concentration gradient. Movement down a concentration gradient is a characteristic of passive transport.
The oil and vinegar in your salad dressing remain separate from one another due to the _____ properties of the oil.
hydrophobic- Oils and other fats are water-fearing or hydrophobic and will not dissolve in water-based solutions such as vinegar.
A scientist notes that an ornamental grass grown in a creek bed is taller than the same type of grass grown on the creek bank. The scientist suspects that this difference is due to water availability. This proposed explanation is a(n) __________.
hypothesis- A hypothesis is a proposed explanation for the observation of the height of the vegetation. The actual reason may be different and would only be found through making a prediction and testing that prediction.
Aerobic cellular respiration completely breaks down a glucose molecule through glycolysis and the citric acid cycle. However, these two processes yield only a few ATPs. The majority of the energy the cell derived from glucose is __________.
in NADH and FADH2- The energy in the electrons carried by these molecules is used to drive the synthesis of ATP in the electron transport chain and chemiosmosis.
The plant cell wall
is a protective structure made of cellulose fibrils.
During cellular respiration, the energy in glucose
is carried by electrons
Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment
is hypotonic to the protozoan.
Protein synthesis requires the use of mRNA, which
is translated by the ribosomes into the amino acid sequences of proteins.
what makes a bond ionic?
it is so polar that the electrons are transfered to the more electronegative element, and their charges attract them to one another.
The maximum size of a cell is limited by _____.
its need for enough surface area to make exchanges with its environment- Because volume increases at a faster rate than surface area, larger cells have proportionately less plasma membrane surface area.
as cell size increases...
its surface area and volume ratio will decrease to accommodate for increase in cell size
Sports physiologists at an Olympic training center want to monitor athletes to determine at what point their muscles begin to function anaerobically. They could do this by checking for a buildup of __________.
lactic acid- In humans, muscle cells switch to lactic acid fermentation after becoming anaerobic.
nuclear envelope
layer of two membranes that surrounds the nucleus of a cell
Recent data presented in the Scientific Thinking module suggests that heat-generating brown fat is most active in __________.
lean people exposed to cold temperatures- The first study suggests that weight and temperature might have an effect on brown fat activity levels; the second study confirms that thin individuals exposed to cold temperatures had the highest brown fat activity levels.
In their mechanism of action, a difference between lipid-soluble and water-soluble hormones is that _____.
lipid-soluble hormones may enter the nucleus of the target cell, whereas water-soluble hormones do not- Water-soluble hormones typically bind to plasma membrane proteins, initiating signal transduction pathways. Lipid-soluble hormones typically enter the cell and bind with intracellular receptors. In the nucleus, the hormone-receptor complex affects gene transcription.
fats
lipids that are solid at room temperature
In cellular respiration, glucose __________ electrons, whereas __________ electrons.
loses ... oxygen gains- During cellular respiration, glucose loses electrons and oxygen gains electrons. Oxidation and reduction always go together, as electron transfer requires both a donor and an acceptor.
Oxidation is the ________, and reduction is the ___
loss of electrons; gain of electrons
The cells of a person with adrenoleukodystrophy (ALD) swell with a buildup of fatty acids. In other words, fatty acids are not being broken down. Which organelle is most likely failing to function correctly?
lysosome- This organelle functions to digest materials in the cell.
A scientist wants to study the enzymes of the citric acid cycle in eukaryotic cells. What part of the cell would she use as a source of these enzymes?
mitochondrial matrix- The water-soluble citric acid cycle intermediates and enzymes of a eukaryotic cell are found in the mitochondrial matrix. The matrix corresponds to the cytoplasm of the bacterium from which mitochondria are descended.
In active transport,
molecules move across the plasma membrane against their concentration gradient-Molecules move against their concentration gradient in active transport.
chemical signals
molecules secreted by cells into the extracellular fluid
The atoms in the molecule of water shown below are held together by which type of bond?(Figure 1)
polar covalent bond- Correct. The hydrogen and oxygen atoms do not equally share their electrons, which results in the formation of electronegative oxygen atoms and electropositive hydrogen atoms. These are then able to interact with other water molecules to form hydrogen bonds.
A protein containing more than one polypeptide chain exhibits the ________ level of protein structure.
quaternary
Three stages of hormone signaling
reception, signal transduction, response
Secretory proteins are
released from the cell through the plasma membrane.
retrospective observational study
seeks information about variables' values in the past
prospective observational study
seeks information about variables' values to occur in the future
Which characteristic promoted the utilization of lipids as the first cell membrane?
self-assembly into a simple membrane
proteins function depends on its ...
shape
RNA
single-stranded nucleic acid that contains the sugar ribose
How many turns of the Calvin cycle are required to produce one molecule of glucose?
six- It requires six turns of the Calvin cycle to fix six molecules of carbon dioxide, forming two G3P molecules that can be synthesized into glucose.
The lipids in a cell membrane are arranged _____.
so that the nonpolar parts of two lipids point toward each other- A phospholipid bilayer can exist as a stable boundary between two aqueous compartments because the molecular arrangement shelters the hydrophobic tails of the phospholipids from water while exposing the hydrophilic heads to water.
Which meal is high in fiber, low in saturated fats, and high in unsaturated fats?
spaghetti noodles with olive oil and broccoli
potential energy
stored energy
The Golgi apparatus
stores, modifies, and packages proteins.
The photosynthetic event known as the Calvin cycle occurs in the __________.
stroma- The thylakoids of the chloroplast are the sites of the light reactions, whereas the Calvin cycle occurs in the stroma.
The primary structure of a protein is
the amino acid sequence of the polypeptide chain.
Amino acids can be distinguished from one another by
the chemical properties of their R groups.
Which characteristic of a protein will remain intact if the protein is denatured?
the number of amino acids in the protein
Plasma membranes are selectively permeable. This means that
the plasma membrane allows some substances to enter or leave a cell more easily than others.
To enter or leave any cell, substances must pass through _____.
the plasma membrane- The plasma membrane defines the external boundary of the cell.
An immune system cell called the plasma cell produces thousands of antibodies (a type of protein) per second for release into the body. What type of intracellular structure would you expect to be very prominent within the cell?
the rough endoplasmic reticulum
GPCRs are receptor proteins found in the plasma membrane that are important for cellular communication. What cellular structure makes GPCRs?
the rough endoplasmic reticulum
Carbohydrates
the starches and sugars present in foods
The partial charges in a water molecule occur because of _____.
the unequal sharing of electrons between hydrogen and oxygen- Because oxygen is more electronegative than hydrogen, electrons of the polar bond spend more time closer to the nucleus of the oxygen atom, resulting in a slight negative charge on the oxygen atom and slight positive charges on the hydrogen atoms
The light reactions take place in the _________ and the Calvin cycle takes place in the _________.
thylakoids; stroma- Within the chloroplast, the light reactions take place in the flattened sacs called thylakoids and the Calvin cycle takes place in the thick fluid called the stroma.
As cell size increases, the
volume increases proportionally more than the surface area
Aquaporins are proteins that facilitate the transport of __________ across the membrane.
water- Aquaporins are a newly discovered class of transport proteins that transport water in cells with very high water permeability needs.
Where do the electrons needed by photosystem II come from?
water- The splitting of water molecules is the source of electrons for photosystem II.
hyrdogen bonds
weak chemical bonds formed between two covalently bonded molecules (i.e. H2O & NH4) They are important in the chemistry of cells
Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic?
whether or not the cell is partitioned into compartments by internal membranes-Prokaryotic cells lack any internal membranous compartmentalization whereas eukaryotic cells have extensive membrane-bound organelles.
