BIOL1A LEC EXAMS 1-4

Which of the following is true of the nucleotide shown below?

It is a purine nucleotide found in DNA

Which of these is an example of inductive reasoning?

Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic.

You disrupt all hydrogen bonds and amino acid R group interactions in a protein. What level of structure will be preserved?

primary structure

In the process of science, which of these is tested?

a hypothesis

Carbon has 4 electrons in its outermost shell and hydrogen has 1 electron in its outermost electron shell. A carbon atom can form covalent bonds with how many hydrogen atoms?

4

Which pair of elements would likely have similar valence shells and thus similar chemical behavior?

nitrogen and phosphorus

Why does ice float in liquid water?

Hydrogen bonds stabilize and keep the molecules of water in ice farther apart than the water molecules of liquid water.

Which bond shown below shows a hydrogen bond that is possible?

i

The most significant role played by pH buffers is to:

limit major shifts in the amount of H+ and OH- in solution.

Water:

has cohesive properties

Amino acids are acids because they always possess ___ as a functional group.

carboxyl

What component of amino acid structure varies among different amino acids?

the components of the R group

Which of these classes of biological molecules does NOT form polymers?

lipids

What is a hypothesis?

a tentative explanation that can be tested and is falsifiable

Which of the following statements about the 5' end of RNA is correct?

The 5' end has a phosphate group attached to the number 5' carbon of ribose.

An atom consists of 9 protons, 9 neutrons, and 10 electrons. The atom has an outermost electron shell.

8

What is the OH- concentration of a solution with pH 3?

10^(-11) M

The two molecules shown in the figures are best described as

________

structural isomers

The figure below shows the structures of glucose and fructose. These two molecules differ in the _____.

arrangement of carbon, hydrogen, and oxygen atoms

What characteristics do all lipids share?

They are have large hydrophobic regions

Which molecule shown below contains a carbonyl group?

C

Which functional group in nonpolar?

Methyl

Which cellular process would you expect to use a hydrolysis reaction?

Break down of starch into glucose in muscle cells

Testing a candidate cancer chemotherapy drug for safety before it is approved for marketing is an example of what general type of science?

Applied

Which of the following is the process used by the scientific community to ensure the quality of scientific research that is published?

Peer-Review

An atom consists of 9 protons, 9 neutrons and 10 electrons. This atom has a charge of:

-1

Which of the following is the strongest evidence that protein structure and function are correlated?

Denatured (unfolded) proteins do not function normally.

From these options, which is the strongest chemical bond?

covalent bond

Carbon-14 is used to determine the age of ancient objects. If a sample is 17,190 years old and started out with 1000mg of Carbon-14, then how much Carbon-14 is remaining today? The half-life of carbon-14 is 5,730 years.

125mg

Two atoms of hydrogen interact to form a(n):

Nonpolar covalent bond

Which of the following is a monomer?

Glucose

About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?

carbon, hydrogen, nitrogen, oxygen

Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur as enantiomers, or molecules that

____.

are mirror images of one another

How many molecules of water are released during the synthesis of a 20 monomer-long cellulose molecule?

19

Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)?

Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge

charge.

Which of the following best describes the difference between starch and cellulose

Cellulose is a polymer of beta-glucose and forms cross-linked fibers containing many

cellulose polymers that hydrogen bond. Starch is made of alpha-glucose and does not form

cross-linked fibers.

A friend of yours calls to say that his car would not start this morning. He asks for your help. You say that you think the battery must be dead. If so, then jump-starting the car from a good battery will solve the problem. In doing so, you are ____.

stating a hypothesis and using that hypothesis to make a testable prediction

Use the following figure to answer the question. The molecule illustrated in the figure is?

is a cis-unsaturated fatty acid

The difference between an aldose sugar and a ketose sugar is ____.

the position of the carbonyl group

Which of the following is true of unsaturated fats?

They have double bonds in their fatty acid chains.

Which molecule is the final electron acceptor for electrons from photosystem I?

NADP+

An antibiotic that blocks protein synthesis in a bacterium most likely targets which of the following?

Ribosomes

What are the products of the light reactions of photosynthesis?

ATP and NADPH

Which of the following would diffuse through the lipid bilayer of a plasma membrane most rapidly?

CO2

Which of the following terms most precisely describes the cellular process of breaking down large molecules into smaller ones?

catabolic pathways

Which structure is common to plant and animal cells?

mitochondria

In which of the following organelles would you expect to find digestive enzymes?

Lysosome

The purpose of the Citric Acid Cycle (Krebs Cycle) is:

To generate NADH for the electron transport chain

According to the fluid mosaic model, a membrane ____.

is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins

During a laboratory experiment, you discover that an enzyme-catalyzed reaction has a ∆G of -20kcal/mol. If you double the amount of enzyme in the reaction, what will be the ∆G for the new

reaction?

-20 kcal/mol

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a H+ gradient across the membrane. In this bacterial cell, phosphate transport is an example of _____.

secondary active transport

Which of the following processes occurs during the Calvin cycle (dark reactions of photosynthesis)?

oxidation of NADPH

Which of the following statements about diffusion is true?

It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.

Many herbicides work by targeting the photosynthesis machinery of the plant. A new herbicide is being tested and you are tasked with determining which part of the light reactions is targeted by the new herbicide. You discover that ATP is being produced, but NADPH levels are very low. Which part of the light reactions is the herbicide most likely affecting?

Photosystem I

The membranes of winter wheat are able to remain fluid when it is extremely cold by ________.

increasing the proportion of unsaturated phospholipids in the membrane

An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?

cell-cell recognition

In chloroplast, an electron transport chain pumps protons from the stroma into the thylakoid space, whereas in mitochondria, an electron transport chain pumps protons from the ______.

matrix to the intermembrane space

Which of the following describes what would happen to an animal cell in a hypotonic solution?

The net movement of water would be into the cell, causing the cell to burst.

P680+ is said to be the strongest biological oxidizing agent. Given its function, why is this necessary?

It obtains electrons from the oxygen atom in a water molecule, so it must have a stronger attraction for electrons than oxygen has.

Which of the following is the most common pathway taken by a newly synthesized protein that will be secreted by a cell?

rough ER → Golgi → transport vesicle → plasma membrane

Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products?

2 NAD+, 2 pyruvate, and 2 ATP

The oxygen consumed during cellular respiration is directly involved in which of the following

processes or events?

the electron transport chain

The force driving simple diffusion is _______, while the energy source for active transport is ______.

a concentration gradient; ATP hydrolysis

Which of the following statements correctly describes osmosis?

In osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.

Which of the following sequences describes the path by which electrons travel downhill energetically in aerobic respiration?

glucose → NADH → electron transport chain → oxygen

Which color light absorbed the least by chlorophyll?

Green

The difference between pinocytosis and receptor-mediated endocytosis is that ________.

pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated

endocytosis offers more selectivity

A cell with a predominance of rough endoplasmic reticulum is most likely ______.

producing large quantities of proteins for secretion

Which of the summary statements below describes the results of the following reaction?

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

C6H12O6 is oxidized and O2 is reduced.

Which of the following structures form cytoplasmic channels that connect adjacent plant cells through the cell walls?

plasmodesmata

Which of the following is the original source of electrons for photosynthesis?

Water

A reaction profile is shown above. Which of the following would be true for this reaction? Note: 1= activation energy, 2 = ΔG, 3 = total energy of reaction

The ΔG is positive

Where are the proteins of the electron transport chain for cellular respiration located?

mitochondrial inner membrane

Which of the following statements describes a central role that ATP plays in cellular metabolism?

Hydrolysis of ATP is an exergonic reaction that can be coupled to endergonic reactions in

the cell.

Which of the following statements about NAD+ is true?

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

Which of the following is a major difference between prokaryotic cells and eukaryotic cells?

Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.

In which reactions of cellular respiration does oxidative phosphorylation occur?

in both the citric acid cycle and the electron transport chain

The evolution of eukaryotic cells most likely involved

_____.

endosymbiosis of an oxygen-using bacterium in a larger bacterial host the endosymbiont evolved into mitochondria

What is the function of the pigment molecules in a light-harvesting complex in the thylakoid membranes?

They absorb and transfer light energy to the reaction-center chlorophyll.

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

anaphase I of meiosis

Which diagram shows a cell in Metaphase II of Meiosis in a species whose body cells are 2n=4?

A

Autosomal chromosomes

are chromosomes 1 through 22 in humans

An adult male is heterozygous for one gene (Bb, not on a sex chromosome), and also carries a recessive X-linked allele called h. What proportion of his sperm will carry the recessive b and h

alleles together?

1/4

At which phase of the cell cycle do centrioles begin to move apart in animal cells?

prophase

To calculate the recombination frequency between two genes, A and B, which cross should you do?

AaBb x aabb

During prometaphase, microtubules begin to attach to which structure?

The kinetochores

Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their

first child will have albinism?

25%

Which of the following individuals will inherit an X-linked allele from a man who expresses the trait?

all of his daughters

Which of the following statements about the law of independent assortment or the law of segregation is correct?

The law of independent assortment describes the behavior of two or more genes relative to

one another.

Dawn is diagnosed with Huntington's disease at age 50. Huntington's disease has an autosomal dominant pattern of inheritance and the individuals with Huntington's are likely heterozygous. What is the chance she will pass the Huntington's allele on to her children?

50%

Meiosis II is similar to mitosis in that

sister chromatids separate during anaphase.

Use the following map of four genes on a chromosome to answer the question below. Between which two genes would you expect the lowest frequency of recombination?

A and W

Experimentally, you determine that two hypothetical genes F and Y are 31 map units apart. You know that a third gene, H is located in between genes F and Y and is 14 map units from gene F. How far apart are genes H and Y?

17

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization (dissolution). Thus, Taxol stops mitosis by interfering with which of

the following structures or processes?

the mitotic spindle

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this

organism?

HT

Nondisjunction during Meiosis results in gametes that have one too many or one too few chromosomes. When in Meiosis can nondisjunction occur?

Either Anaphase I or Anaphase II

Which of the following events occurs during interphase of the cell cycle?

replication of the DNA

The pedigree below shows the inheritance of colorblindness, an X-linked recessive trait, in a family.

Which of the following individuals must be a carrier for colorblindness?

III-4

An allele is best defined as

Different versions of the same gene

Mice have 2n=40 chromosomes in their somatic cells. The number of chromosomes in a mouse sperm cell and a mouse skin cell are, respectively:

20, 40