Biology Exam 2

Front 1

When biologist wish to study the internal ultrastructure of cells, they can achieve the finest resolution by using what kind of microscope?

Back 1

A transmission electron microscope.

Front 2

What is the primary objective of cell fractionation?

Back 2

To separate the major organelles so that their particular functions can be determined.

Front 3

What organelle does a prokaryotic cell not have?

Back 3

An endoplasmic reticulum.

Front 4

The evolution of eukaryotic cells most likely involved what process?

Back 4

Endosymbiosis of an aerobic bacterium in a larger host cell - the endosymbiont evolved into mitochondria.

Front 5

Which organelle or structure is absent in plant cells?

Back 5

Centrosomes.

Front 6

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

Back 6

Proteins.

Front 7

Which structure is the site of the synthesis of proteins that may be exported from the cell?

Back 7

The rough endoplasmic reticulum.

Front 8

The liver is involved in detoxification of man poisons and drugs. Which structure is primarily involved in this process and therefore abundant in liver cells?

Back 8

The smooth endoplasmic reticulum.

Front 9

Which animal cell organelle contains enzymes that transfer hydrogen from various substrates to oxygen?

Back 9

Peroxisomes.

Front 10

Thylakoids, DNA, and ribosomes are all components found in what organelle?

Back 10

Chloroplasts.

Front 11

Why isn't the mitochondrion classified as part of the endomembrane system?

Back 11

Its structure is not derived from the endoplasmic reticulum or the golgi complex.

Front 12

Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

Back 12

Cytoskeletal structures.

Front 13

Out of all the structures that determine and maintain the structure of plant cells, which one is distinct from the others in composition?

Back 13

Plant cell walls differ from microtubules, microfilaments, intermediate filaments, and the nuclear lamina.

Front 14

Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through what?

Back 14

Gap junctions.

Front 15

What is the primary function of polysaccharides attached to the glycoproteins and glycolipids of animal cell membranes?

Back 15

To mediate cell-to-cell recognition.

Front 16

What is a protein that spans the phospholipid bilayer one or more times?

Back 16

A transmembrane protein.

Front 17

The cell membranes of Antarctic ice fish might have which of the following adaptations?

Back 17

A high percentage of polyunsaturated fatty acids.

Front 18

What kinds of molecules pass through a cell membrane most easily?

Back 18

Small and hydrophobic.

Front 19

What would likely move through the lipid bilayer of a plasma membrane most rapidly out of CO2, an amino acid, glucose, K+, and starch?

Back 19

CO2.

Front 20

What is diffusion?

Back 20

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

Front 21

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 pH gradient across the membrane- more acidic outside the cell than inside the cell. What is phosphate transport an example of?

Back 21

Cotransport.

Front 22

What is the voltage across a membrane called?

Back 22

Membrane potential.

Front 23

What would increase the electrochemical potential across a membrane?

Back 23

A proton pump.

Front 24

An organism with a cell wall would most likely be unable to take in materials through what?

Back 24

Phagocytosis.

Front 25

White blood cells engulf bacteria through what process?

Back 25

Phagocytosis.

Front 26

What kind of pathways consume energy to build up polymers from monomers?

Back 26

Anabolic pathways.

Front 27

What is the first law of thermodynamics?

Back 27

Energy cannot be created nor destroyed.

Front 28

Whenever energy is transformed, there is always an increase in what?

Back 28

Entropy of the universe.

Front 29

What can a system at chemical equilibrium not do?

Back 29

Work.

Front 30

Out of pentose sugar, a DNA nucleotide, an RNA nucleotide, an amino acid with three phosphate groups attached, and a phospholipid, which is most similar in structure to ATP?

Back 30

An RNA nucleotide because they employ the same sugar, ribose.

Front 31

Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier know as the reaction's what?

Back 31

Activation energy.

Front 32

The active site of an enzyme is the region that is involved in what?

Back 32

The catalytic reaction of the enzyme.

Front 33

How do enzymes increase the rate of chemical reaction?

Back 33

By lowering activation energy barriers.

Front 34

What is the term for metabolic pathways that release stored energy by breaking down complex molecules?

Back 34

Catabolic pathways.

Front 35

When electrons move closer to a more electronegative atom, what happens?

Back 35

The more electronegative atom is reduced, and energy is released.

Front 36

When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes what?

Back 36

Oxidized.

Front 37

When a molecule of NAD+ gains a hydrogen atom (not a proton), the molecule becomes what?

Back 37

Reduced.

Front 38

The molecules that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction does what?

Back 38

It loses electrons and loses potential energy.

Front 39

What organelle contains hydrolytic enzymes?

Back 39

Lysosomes.

Front 40

What organelle do we find grana and thylakoids in?

Back 40

Chloroplasts.

Front 41

In what organelles does photosynthesis take place?

Back 41

Chloroplasts.

Front 42

What organelles are involved in the decomposition of peroxide, H2O2?

Back 42

Peroxisomes.

Front 43

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

Back 43

Mitochondria.

Front 44

Name one structure that contain the 9+2 arrangement of microtubules consisting of nine doublets of microtubules surrounding a pair of single microtubules?

Back 44

Flagella.

Front 45

In what organelle proteins may be finally sorted and modified before they are packaged into vesicles to be transported to their final destination?

Back 45

Golgi apparatus.

Front 46

What is the name of the structure that takes up most of the volume of the plant cell?

Back 46

Vacuole.

Front 47

What is the name of the microscopic tunnels hat connect adjacent plant cells and allow direct transport between their cytoplasms?

Back 47

Plasmodesmata.

Front 48

What organelles found in plant cells contain pigments that color petals, fruits, etc.?

Back 48

Plastids.

Front 49

What are phospholipids?

Back 49

Amphipathic molecules.

Front 50

What are cholesterol molecules a part of?

Back 50

The plasma membrane.

Front 51

What are peripheral proteins?

Back 51

Proteins that adhere only temporarily to a membrane with which they are associated.

Front 52

What provides the energy for diffusion?

Back 52

The concentration gradient.

Front 53

When does phosphorylation occur?

Back 53

When a phosphate group is transferred to some other compound.

Front 54

When does competitive inhibition happen?

Back 54

When the substrate and the inhibitor compete for the active site of the enzyme.

Front 55

What two components do some enzymes consist of?

Back 55

A protein called the apoenzyme and another chemical component called a cofactor.

Front 56

The difference in a lipid and protein composition between the membranes of the endomembrane system is largely determined by what?

Back 56

The function of the Golgi apparatus in sorting and directing membrane components.

Front 57

If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction?

Back 57

Sperm, larynx, and trachea: cells and tissues that contain flagella or cilia.

Front 58

Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater?

Back 58

Water will leave the cells, causing them to shrivel and collapse.

Front 59

What statement would be representative of the second law of thermodynamics?

Back 59

Cells require a constant input of energy to maintain their high level of organization.

Front 60

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

Back 60

-20 kcal/mol.