Exam 2

Question 1

Which of the following statements is NOT part of the cell theory?
~ All organisms are composed of one or more cells
~ All cells come from other cells by division
~ Cells are the smallest living things
~ All cells are composed of molecules and organelles

Answer 1

All cells are composed of molecules and organelles

Question 2

The most important factor that limits the size of a cell is the

Answer 2

surface-area-to-volume ratio of the cell.

Question 3

Which of the following is NOT a characteristic of all prokaryotic cells?
~ Ribosomes
~ Cell wall
~ DNA
~ Pili

Answer 3

Pili

Question 4

Which of the following is found in eukaryotic cells but not in prokaryotic cells?
~ Cell wall
~ Plasma membrane
~ Endoplasmic reticulum
~ Ribosomes

Answer 4

Endoplasmic reticulum

Question 5

Which of the following nuclear structures is NOT correctly matched with its function?
~ the nucleolus –> site of rRNA synthesis
~ Nuclear pores –> allow passage of molecules into and out of the nucleus
~ Nuclear envelope –> separates the contents of the nucleus from the cytoplasm
~ Nuclear lamina –> produces ribosomes

Answer 5

Nuclear lamina –> produces ribosomes

Question 6

A protein that is secreted from the cell takes which pathway?

Answer 6

Rough ER –> transport vesicle –> Golgi –> secretory vesicle –> plasma membrane

Question 7

Mitochondria

Answer 7

have a highly folded inner membrane

Question 8

The cytoskeleton includes

Answer 8

intermediate filaments made of twisted fibers of vimentin and keratin

Question 9

Microfilaments

Answer 9

are essential to cell division and muscle contraction

Question 10

Which of the following statements about the plant cell wall is NOT true?
~ It functions in support and protection
~ It lies just inside the plasma membraine
~ The primary cell wall is formed while a cell is growing
~ It is composed primarily of polysaccharides

Answer 10

It lies just inside the plasma membrane

Question 11

Which of the following types of cell connection is correctly matched with its function?
~ Adherens junction –>blocks substances from passing between cells
~ Plasmodesmata–> communication between cells
~ Septate junction –> attaches the cytoskeleton of one cell to the cytoskeleton of another cell
~ All are correctly matched

Answer 11

Plasmodesmata –> communication between cells

Question 12

A covalent bond between a hydrogen atom and an oxygen atom represents what kind of energy?

Answer 12

Potential energy

Question 13

During a redox reaction, the molecule that gains an electron is

Answer 13

reduced and now has a higher energy level

Question 14

When a bear eats a salmon, some of the energy stored in the salmon is used by the bear for its activities and growth. Much of the energy originally in the salmon is dissipated as heat. This is an example of

Answer 14

the Second Law of Thermodynamics

Question 15

An endergonic reaction has which of the following properties?
~ +deltaG and the reaction is spontaneous
~ +deltaG and the reaction is not spontaneous
~ -deltaG and the reaction is spontaneous
~ -deltaG and the reaction is not spontaneous

Answer 15

+delatG and the reaction is not spontaneous

Question 16

The molecule ATP is less stable than ADP+ Pi because

Answer 16

the negatively charged phosphates repel each other

Question 17

What is activation energy?

Answer 17

The energy required to initiate a chemical reaction

Question 18

Which of the following is NOT a property of an enzyme?
~ An enzyme reduces the activation energy of a reaction
~ An enzyme lowers the free energy of the reactants
~ An enzyme does not change as a result of the reaction
~ An enzyme works in both the forward and reverse direction of a reaction

Answer 18

An enzyme lowers the free energy of the reactants

Question 19

Which statement about the influence of temperature on enzymes is NOT true?
~ All enzymes have the same intrinsic optimal temperature
Raising the temperature may increase the activity of an enzyme
~ Some enzymes are stable at the boiling point of water
~ Raising the temperature may decrease the activity of an enzyme

Answer 19

All enzymes have the same intrinsic optimal temperature

Question 20

Coenzymes

Answer 20

can be metal ions, can bind in active sites and participate directly in a catalytic reaction, are sometimes vitamins.

Question 21

In competitive inhibition,

Answer 21

an inhibitor molecule binds to the active site of an enzyme, so the substrate cannot bind

Question 22

Anabolism is

Answer 22

the buildup of molecules

Question 23

What is the purpose of cellular respiration?

Answer 23

To make ATP to power cellular activities

Question 24

In redox reactions,

Answer 24

one substance loses electrons and the other gains electrons

Question 25

ATP production during glycolysis

Answer 25

requires an enzyme, occurs in the cytoplasm, occurs via substrate-level phosphorylation

Question 26

The reaction of the Krebs cycle occur in the

Answer 26

matrix of the mitochondria

Question 27

In eukaryotic cells, the molecules that form the electron transport chain and ATP synthesis are found in

Answer 27

the inner mitochondrial membrane

Question 28

The movement of electrons down the electron transport chain

Answer 28

pumps protons into the intermembrane space

Question 29

The P/O ration

Answer 29

has changed over time due to our increased understanding of how ATP synthase works

Question 30

The production of the vast majority of the ATP molecules within the cells of your body is powered by electrons removed

Answer 30

during the citric acid cycle,

Question 31

When ATP is in excess within the cell, which of the following happens? ~ Phosphofructokinase is inhibited ~ Citrate synthetase is inhibited ~ Pyruvate dehydrogenase is inhibited ~ All of the above

Answer 31

All of the above

Question 32

Which pathway is present in both fermentation and aerobic respiration?

Answer 32

Glycolysis

Question 33

Which of the following is NOT true of bata oxidation of fatty acids? ~ The process occurs in the matrix of the mitochondrion ~ Acetyl goups are removed form fatty acids chain ends ~ Respiration of a 6-carbon fatty acid molecule yields fewer ATP than respiration of a 6-carbon glucose molecule ~ All of the above

Answer 33

All of the above

Question 34

Proteins

Answer 34

are broken down into amino acids, which can then drive ATP synthase

Question 35

The light-dependent reactions of photosynthesis

Answer 35

produce ATP and NADPH and occur in the thylakoid membranes

Question 36

When a plant grows, its increase in biomass comes from

Answer 36

the carbon from CO2 in the air

Question 37

The gas released as a product of photosynthesis comes from

Answer 37

H2O

Question 38

Which of the following statments about photons is NOT accurate? ~ Photons are discrete bundles of light energy ~ Phostons are found at all wavelengths of ligh ~ Energy from photons can be transferred to pigment molecules ~ All photons have the same amount of energy

Answer 38

All photons have the same amount of energy

Question 39

Chlorophyll a

Answer 39

reflects green light

Question 40

how is a reaction center pigment in a photosystem different from a pigment in the antenna complex?

Answer 40

The reaction center pigment loses an electron when it absorbs light energy

Question 41

In eukaryotes, photosystems are found

Answer 41

in the thylakoid membrane

Question 42

In the light-dependent reactions of photosynthesis, photosystme 1 functions to ________, and photosystem 2 function to ________.

Answer 42

reduce NADP+; oxidize H2O

Question 43

The overall flow of elecctrons in the ligh reactions in from

Answer 43

H2O to NADPH

Question 44

Which of the following is NOT accurate about carbon fixation? ~ It results in the production of CO2 ~ It requires NADPH to provide electrons and protons ~ It requires energy provided by the light-dependent reactions ~ It occurs in the stroma

Answer 44

It results in the production of CO2

Question 45

The overall process of photosynthesis

Answer 45

results in the reduction of CO2 and the oxidation of H2O

Question 46

Which of the following is a similarity between C4 and CAM plants? ~ both use PEP carboxylase to initially fix carbon ~ Both carry out carbon fixation and the Calvin cycle in separate cell types ~ both carry out the Calvin cycle at night ~ All of the above

Answer 46

Both use PEP carboxylase to initially fix carbon