Test Bank Anatomy And Physiology From Science to Life, 2nd Edition by Jenkins, Gail

1.

A human cell placed in a 2% NaCl solution (a hypertonic solution) would:

A)

swell and lyse.

B)

have a low osmotic pressure compared to the solution.

C)

maintain its shape.

D)

maintain a very high hydrostatic pressure.

E)

exhibit no change.

2.

A red blood cell placed in distilled (pure) water (which is hypotonic) would:

A)

Swell and burst

B)

Shrink

C)

Swell, then shrink as equilibrium is reached

D)

Neither shrink nor swell

E)

Maintain a low hydrostatic pressure.

3.

A red blood cell placed in a hypotonic solution would:

A)

Crenate

B)

Swell, then crenate as equilibrium is reached

C)

Neither crenate nor swell

D)

Swell and lyse

E)

Have a low osmotic pressure compared to the solution.

4.

Which statement is the most correct regarding the processes of transcription and translation?

A)

The nucleotide sequence in an mRNA codon is an exact copy of the DNA triplet that coded for it, except that uracil replaces adenine.

B)

The nucleotide sequence in an mRNA codon is an exact copy of the DNA triplet that coded for it, except that uracil replaces thymine.

C)

The nucleotide sequence in an rRNA codon is an exact copy of the DNA triplet that coded for it, except that uracil replaces adenine.

D)

The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it, except that uracil replaces adenine.

E)

The nucleotide sequence in a tRNA anticodon is an exact copy of the DNA triplet that coded for it except that uracil replaces thymine.

5.

If cells are placed in a hypotonic solution containing a solute to which the membrane is impermeable, what could happen?

A)

The cells would swell and cell lysis could occur.

B)

The cells would lose water and crenate.

C)

The cells would crenate at first, but then reach equilibrium with the surrounding solution.

D)

The cells would show no change.

E)

The cells would maintain a low hydrostatic pressure.

6.

Which of the following cells types would you expect to have an unusually high abundance of free ribosomes?

A)

Fibroblasts

B)

Osteoblasts

C)

Skeletal muscle cells

D)

Liver cells (which produce many of the proteins found in blood)

E)

Chondroblasts

7.

Which of the following is the major positive ion in the extracellular fluid?

A)

Potassium

B)

Sodium

C)

Magnesium

D)

Chloride

E)

Hydrogen

8.

__________ can be thought of as “cell eating” and is practiced frequently by white blood cells, which use it to neutralize bacteria, viruses, and dead or dying cells.

A)

Pinocytosis

B)

Exocytosis

C)

Phagocytosis

D)

Autolysis

E)

Hydrolysis

9.

Which of the following is FALSE regarding the sodium-potassium pump?

A)

It is a type of primary active transport antiporter.

B)

It changes conformation after being phosphorylated, and expels sodium from inside the cell.

C)

It relies on the hydrolysis of ATP in order to function.

D)

It imports three K+ for every 2 Na+ it exports from the cell.

E)

It releases its phosphate group after it binds to extracellular K+.

10.

During __________ the chromosomal centromeres split and the chromosomes migrate to opposite ends of the cell.

A)

Metaphase

B)

Anaphase

C)

Telophase

D)

Prophase

E)

S phase

11.

Which of the following statements is most correct regarding the sodium-potassium pump?

A)

The ATP driven pump operates as a symport system.

B)

The pump transports 3 potassium ions into the cell for every 2 sodium ions it transports out of the cell.

C)

Phosphorylation of the ATPase transport protein causes a conformational change resulting in the expulsion of sodium into the extracellular fluid.

D)

When potassium binds to the ATPase transport protein, the protein is phosphorylated.

E)

It is a secondary transport pump.

12.

Which of the following is true regarding the generation of a membrane potential?

A)

When the sodium-potassium pump is active, potassium is pumped into the cell twice as fast as the sodium is pumped out, causing the membrane potential.

B)

Potassium and sodium ions can “leak” through the cell membrane due to diffusion.

C)

In the polarized state, sodium and potassium ions concentrations are in static equilibrium.

D)

The membrane potential is based exclusively on passive processes.

E)

The membrane is impermeable to sodium and potassium.

13.

If a 0.92% saline (NaCl) solution is isotonic to a cell, a 0.3% NaCl solution:

A)

would cause the cell to shrink.

B)

would result in water movement into the cell.

C)

would cause the cell to crenate.

D)

is hypertonic to the cell.

E)

is hyperosmotic to the cell.

14.

Which of the following would NOT increase the rate of diffusion?

A)

A decrease in the size of the diffusing particle.

B)

An increase in the concentration gradient.

C)

An enzyme acting as a catalyst.

D)

An increase in the temperature.

E)

A decrease in the thickness of the membrane across which diffusion was occurring.

15.

Which of the following is NOT an example of hydrogen bonding?

A)

The bonds formed between base pairs of nucleotides in DNA.

B)

The bonds formed between neighboring amino acids to form a protein’s secondary structure.

C)

The bonds formed between amino acids to form a protein’s primary structure.

D)

The bonds formed between molecules of H2O.

E)

The bonds formed between the hydroxyl groups of cholesterol molecules and the surrounding polar heads of the phospholipids in the plasma membrane.

16.

Which of the following is a FALSE statement regarding the cytoplasmic organelles?

A)

The Golgi complex is the site of protein transcription.

B)

The smooth endoplasmic reticulum in muscle cells serve to store Ca2+ (ionic calcium).

C)

Mitochondria are sites for the processes involved with cellular respiration (using oxygen to produce ATP), and contain their own DNA.

D)

Ribosomes consist of large and small subunits, both of which are made in the nucleolus of the cell.

E)

Lysosomes are membrane enclosed vesicles that contain powerful digestive enzymes that work best at an acidic pH.

17.

In which phase of the cellular cycle does DNA replication occur?

A)

Prophase

B)

Metaphase

C)

S phase

D)

G2 phase

E)

Telophase

18.

If a tRNA had an AGC anticodon, it could attach to a(n) ____________ mRNA codon.

A)

UGA

B)

AUG

C)

UCG

D)

TCG

E)

GAU

19.

The cell does not need to expend energy (ATP) in order to perform:

A)

exocytosis.

B)

receptor mediated endocytosis.

C)

simple diffusion.

D)

active transport.

E)

phagocytosis.

20.

Put the steps of the sodium-potassium pump in the correct order.

 1) potassium binds to protein pump

 2) sodium binds to protein

 3) release of potassium into ICF

 4) hydrolysis of ATP

 5) expelling of sodium

A)

1, 2, 3, 4, 5

B)

2, 4, 5, 1, 3

C)

3, 4, 2, 5, 1

D)

5, 3, 4, 2, 1

E)

3, 2, 4, 1, 5

21.

Put the steps of the sodium-potassium pump in the correct order.

1) potassium binds to protein pump

2) sodium binds to protein

3) phosphate group is released from protein pump 

4) release of potassium into ICF

5) hydrolysis of ATP

6) expelling of sodium

A)

1, 2, 3, 4, 5, 6

B)

2, 5, 6, 1, 3, 4

C)

3, 4, 2, 6, 5, 1

D)

5, 6, 3, 4, 2, 1

E)

3, 2, 4, 6, 1, 5

22.

The smooth endoplasmic reticulum found in muscle cells has a special name, the sarcoplasmic reticulum, and is responsible for storing and releasing which important ion?

A)

Ca2+

B)

Mg2+

C)

Na+

D)

K+

E)

Cl-

23.

An example of phagocytosis would include:

A)

a cell in the intestinal tract absorbing glucose.

B)

a muscle cell contracting.

C)

a white blood cell ingesting a bacterium.

D)

a red blood cell transporting oxygen.

E)

a goblet cell secreting mucous.

24.

The sodium potassium pump transports _____________ Na+ to the extracellular fluid for every ______________ K+ that it transports into the intracellular fluid.

A)

2, 3

B)

1, 2

C)

3, 1

D)

3, 2

E)

2, 2

25.

Ribosomes are the sites where __________ occurs.

A)

Translation

B)

Transcription

C)

Mitosis

D)

Phagocytosis

E)

Apoptosis

26.

If a transport protein moves two substances in the same direction, it is called a(n):

A)

Antiporter

B)

Carrier protein

C)

Symporter

D)

Clathrin coated pit

E)

Phagosome

27.

What are the three main parts of a eukaryotic cell?

A)

Plasma membrane, organelles, cytoplasm

B)

Plasma membrane, organelles, nucleus

C)

Plasma membrane, cytoplasm, organelles

D)

Plasma membrane, cytoplasm, nucleus

E)

Plasma membrane, cytosol, organelles

28.

Plasma membranes consist of what three components?

A)

Phospholipids, glycoproteins, water

B)

Proteins, cholesterol, fatty acids

C)

Cholesterol, fatty acids, glycolipids

D)

Proteins, phospholipids, cholesterol

E)

Water, proteins, fatty acids

29.

What regions of a phospholipid molecule are hydrophobic?

A)

Head region

B)

Tail region

C)

Both head and tail

D)

Neither head, nor tail

E)

None of the above

30.

What regions of a phospholipid molecule are polar?

A)

Head region

B)

Tail region

C)

Both head and tail

D)

Neither head, nor tail

E)

None of the above

31.

This is the only polar portion of a cholesterol molecule and it forms hydrogen bonds with the polar heads of phospholipids.

A)

–OH group

B)

–CH3 group

C)

–CH4 group

D)

–OOH group

E)

None of the above

32.

This type of membrane protein will extend throughout the entire membrane touching both the intracellular fluid and the extracellular fluid.

A)

Integral proteins

B)

Transmembrane proteins

C)

Peripheral proteins

D)

Both transmembrane and peripheral proteins

E)

All of the above

33.

This component of a cell membrane enables it to produce chemical products.

A)

Receptors

B)

Phospholipids

C)

Cholesterol

D)

Enzymes

E)

Ligand

34.

Which of the following is a membrane protein that binds with hormones and neurotransmitters?

A)

Transporters

B)

Receptors

C)

Enzymes

D)

Linkers

E)

Cell Identification markers

35.

This type of membrane protein serves as sort of an anchor, and may connect the plasma membranes of two neighboring cells together.

A)

Transporters

B)

Receptors

C)

Ligand

D)

Ion channels

E)

Linkers

36.

The characteristic of plasma membranes allowing only some substances to move through is known as:

A)

Selective permeability

B)

Concentration gradient

C)

Electrical gradient

D)

Solubility

E)

Transportation

37.

This is a measure of a solution’s ability to change the volume of cells by altering their water content.

A)

Tonicity

B)

Facilitation

C)

Gradient

D)

Osmotic pressure

E)

Hydrostatic pressure

38.

Which of the following does NOT influence the rate of diffusion?

A)

Steepness of the concentration gradient

B)

Mass of the diffusing substance

C)

Thickness of the membrane across which diffusion must occur

D)

Amount of ATP available

E)

Temperature

39.

This is the transport process by which gases move through a membrane.

A)

Osmosis

B)

Active transport

C)

Secondary active transport

D)

Simple diffusion

E)

Endocytosis

40.

In this type of passive transport process a solute, such as glucose, binds to a specific transporter protein on one side of the membrane and is released on the other side after the transporter protein undergoes a change in shape.

A)

Osmosis

B)

Facilitated diffusion

C)

Active transport

D)

Secondary active transport

E)

Endocytosis

41.

In this transport process, the energy from the hydrolysis of ATP is used to drive substances across the membrane against their own concentration gradients.

A)

Primary active transport

B)

Secondary active transport

C)

Facilitated diffusion

D)

Passive diffusion

E)

Osmosis

42.

If the solute concentration is greater in the solution on the inside of a human red blood cell, compared to the solute concentration of the solution that is outside the cell, then what direction will water move?

A)

into the cell

B)

out of the cell

C)

no movement

43.

In this transport process, the energy stored in the Na+ or H+ concentration gradient is used to drive other substances across the membrane against their own concentration gradients.

A)

Primary active transport

B)

Secondary active transport

C)

Facilitated diffusion

D)

Passive diffusion

E)

Osmosis

44.

This is a transport process by which cells secrete vesicular materials into the extracellular fluid.

A)

Endocytosis

B)

Exocytosis

C)

Active transport

D)

Diffusion

E)

Osmosis

45.

This is a transport process by which cells take up extracellular substances within vesicles.

A)

Endocytosis

B)

Exocytosis

C)

Active transport

D)

Diffusion

E)

Osmosis

46.

The extension of the plasma membrane that will surround a microbe outside a macrophage is called a:

A)

Phagocyte

B)

Exterior vesicle

C)

Interior vesicle

D)

Pseudopod

E)

Pinocytosis

47.

The function of the cytosol is.

A)

ATP production

B)

Location of chemical reactions

C)

Production of polypeptides

D)

Digestion of decomposing proteins

E)

Protection of nuclear material

48.

These perform special functions in cellular growth, maintenance and reproduction.

A)

organelles

B)

cytoskeletom

C)

cytoplasm

D)

cytosol

E)

nucleus

49.

This organelle is comprised of microfilaments, intermediate filaments and microtubules.

A)

cytoskeleton

B)

cytoplasm

C)

cilia

D)

flagella

E)

ribosome

50.

This is comprised of a pair of centrioles and pericentriolar materials.

A)

cytoskeleton

B)

cilia

C)

centrosome

D)

flagella

E)

peroxisomes

51.

One type of human cell (a spermatozoan) is capable of movement because it has this type of microtubule.

A)

cilium

B)

flagellum

C)

cytoskeleton

D)

cytosol

E)

intermediate filament

52.

This organelle is studded with ribosomes, which synthesize proteins

A)

rough endoplasmic reticulum

B)

cytosol

C)

nucleus

D)

centriole

E)

mitochondria

53.

This is an organelle that modifies proteins produced elsewhere.

A)

endoplasmic reticulum

B)

Golgi complex

C)

peroxisomes

D)

nucleus

E)

proteasome

54.

These are small flattened curved membranous sacs with bulging edges.

A)

secretory vessels

B)

membrane vessels

C)

cisternae

D)

cis face

E)

trans face

55.

Which organelle oxidizes organic molecules?

A)

peroxisomes

B)

mitochondria

C)

proteasome

D)

ribosomes

E)

lysosomes

56.

Which organelle recycles worn out organelles?

A)

peroxisomes

B)

mitochondria

C)

proteasome

D)

ribosomes

E)

lysosomes

57.

Proteasomes

A)

Perform extracellular digestion

B)

Perform autophagy

C)

Perform autolysis

D)

Degrade faulty cellular proteins

E)

Degrade ATP

58.

Mitochondria

A)

move the cell

B)

generate ATP

C)

produce proteins

D)

oxidize organelles

E)

synthesize glycolipids

59.

Which of the following protects the contents of the nucleus?

A)

nucleic acids

B)

nuclear envelope

C)

nuclear centrosome

D)

cilia

E)

golgi complex

60.

What is the major function of a histone protein?

A)

Protein synthesis

B)

Adds a charge to DNA

C)

Helps organize coiling of DNA

D)

Degrades proteins

E)

Enzymatic effect

61.

This is a long molecule of DNA that contains genes-there are 46 in each body cell.

A)

chromatin

B)

chromatid

C)

chromosome

D)

centromere

E)

centrosome

62.

This is the set of rules that, relating the base triplet sequence of DNA to the corresponding codons of RNA, specifies a sequence of amino acids.

A)

cytokinesis

B)

genomics

C)

anticodons

D)

gene expression

E)

protein synthesis

63.

This binds to an amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation.

A)

mRNA

B)

rRNA

C)

tRNA

D)

DNA

E)

cDNA

64.

This process is division of the cytoplasm.

A)

mitosis

B)

meiosis

C)

cytokinesis

D)

cytosol

E)

centrioles

65.

During which phase do organelles duplicate and centrosome replication begin?

A)

Interphase

B)

Prophase

C)

Metaphase

D)

Anaphase

E)

Telophase

66.

Normally how long does the G2 phase last?

A)

8 hours

B)

4-6 hours

C)

2 hours

D)

24 hours

E)

1 day

67.

During this phase the chromatin fibers condense and shorten into chromosomes that are visible under the microscope.

A)

Interphase

B)

Prophase

C)

Metaphase

D)

Anaphase

E)

Telophase

68.

The function of mitosis is

A)

production of gametes

B)

create more cilia

C)

form flagella

D)

production of proteins

E)

production of new cells

69.

In the maintenance of the cell resting membrane potential,

A)

extracellular sodium levels are high.

B)

cells are more permeable to Na+ than to K+

C)

only passive transport processes are involved.

D)

the inside of the cell is more positive relative to the outside of the cell.

E)

ATP is not needed.

70.

Which of the following an accurate statement regarding the fluid-mosaic model of cell membrane structure?

A)

Phospholipids form a bilayer that is largely impermeable to water soluble molecules.

B)

Phospholipids consist of a non-polar head and two polar tails made of fatty acid chains.

C)

The lipid bilayer is solid at normal body temperature, thus protecting the cell.

D)

Proteins can not span the lipid bilayer and are called peripheral proteins.

E)

The fluidity of the membrane allows it to be impermeable.

71.

Which of the following statements best describes receptor mediated endocytosis?

A)

It is a highly selective process that is the main mechanism for insulin entrance into body cells.

B)

It occurs mainly in phagocytic white blood cells.

C)

It is a passive transport process.

D)

It is important for absorption of solutes in the kidneys and intestines.

E)

It allows for a non-selective way for cells to “sample” the extracellular environment.

72.

During this phase a cleavage furrow forms.

A)

Interphase

B)

Prophase

C)

Metaphase

D)

Anaphase

E)

Telophase

73.

In the diagram, which organelle is responsible for autophagy and autolysis?

A)

C

B)

E

C)

F

D)

J

E)

K

74.

In the diagram, which organelle is used to modify, sort and package proteins for transport?

A)

D

B)

I

C)

J

D)

K

E)

G

75.

In the diagram, which organelle generates ATP through oxidative phosphorylation?

A)

F

B)

G

C)

H

D)

D

E)

I

76.

In the diagram, this structure directs cellular activities.

A)

D

B)

F

C)

G

D)

A

E)

H

77.

In the diagram, which organelle is essential for cells that undergo mitotic division?

A)

A

B)

B

C)

C

D)

D

E)

E

78.

In the diagram this organelle contains the enzyme oxidase which oxidizes organic substances.

A)

C

B)

E

C)

I

D)

J

E)

K

79.

Which of the following represents a carrier protein?

A)

A

B)

B

C)

C

D)

D

E)

E

80.

Which of the following represents a receptor?

A)

B

B)

C

C)

D

D)

E

E)

F

81.

Which of the following represents a linker?

A)

B

B)

C

C)

D

D)

E

E)

F

82.

In the diagram, which one represents facilitated diffusion?

A)

A

B)

B

C)

C

D)

Both a and c

E)

Both b and c

83.

In the diagram, which one represents a hypertonic solution?

A)

A

B)

B

C)

C

D)

Both b and c

E)

All of the above

84.

What does this figure represent?

A)

Fluid mosaic model of the plasma membrane

B)

Cytokinesis

C)

Mitosis

D)

Protein synthesis

E)

Organelle digestion

85.

Where would you see this occur?

A)

Nucleus

B)

Cytoplasm

C)

Smooth endoplasmic reticulum

D)

All of the above

E)

None of the above

86.

What types of bonds are formed between the balls meant to represent amino acids?

A)

Hydrogen

B)

Polar

C)

Peptide

D)

Ionic

E)

Nuclear

87.

Describe briefly what is occurring at each step in the figure.

88.

In the diagram, which one represents anaphase?

A)

A

B)

B

C)

C

D)

D

E)

E

89.

In the diagram, which phase represents the kinetochore microtubules aligning the centromeres along the metaphase plate in the center of the cell?

A)

A

B)

B

C)

C

D)

D

E)

E

90.

During which phase illustrated by the images does the mitotic spindle form?

A)

A

B)

B

C)

C

D)

D

E)

E

91.

What process does Step 1 in this figure represent?

A)

Transcription

B)

Cytokinesis

C)

Mitosis

D)

Translation

E)

Organelle digestion

92.

What does Step 2 in this figure represent?

A)

Transcription

B)

Cytokinesis

C)

Mitosis

D)

Translation

E)

Organelle digestion

93.

In the diagram, which one represents a hypotonic solution?

A)

A

B)

B

C)

C

D)

Both b and c

E)

All of the above

94.

In the diagram, which one represents an isotonic solution?

A)

A

B)

B

C)

C

D)

Both b and c

E)

All of the above

95.

Briefly state the functions of the rough and smooth endoplasmic reticulum.

96.

Briefly list the steps involved in receptor mediated endocytosis of ligands.

97.

Briefly describe the fluid mosaic model.

98.

Briefly describe how proteins go through the Golgi body.

99.

Briefly explain the difference between transcription and translation.

100.

Describe five different functions of embedded membrane proteins.

101.

Compare and contrast primary and secondary active transport.

102.

Compare mitosis to meiosis.

1.

B

2.

A

3.

D

4.

E

5.

A

6.

C

7.

B

8.

C

9.

D

10.

B

11.

C

12.

B

13.

B

14.

C

15.

C

16.

A

17.

C

18.

C

19.

C

20.

B

21.

B

22.

A

23.

C

24.

D

25.

A

26.

C

27.

D

28.

D

29.

B

30.

A

31.

A

32.

D

33.

D

34.

B

35.

E

36.

A

37.

A

38.

D

39.

D

40.

B

41.

A

42.

A

43.

B

44.

B

45.

A

46.

D

47.

B

48.

A

49.

A

50.

C

51.

B

52.

A

53.

B

54.

C

55.

A

56.

E

57.

D

58.

B

59.

B

60.

C

61.

C

62.

D

63.

C

64.

C

65.

A

66.

B

67.

B

68.

E

69.

A

70.

A

71.

A

72.

D

73.

A

74.

D

75.

A

76.

C

77.

B

78.

B

79.

B

80.

B

81.

C

82.

E

83.

C

84.

D

85.

B

86.

C

87.

This figure represents the translative portion of protein synthesis. In step one the initiator tRNA attaches to a start codon. In step two the large and small ribosomal subunits join to form a functional ribosome and initiator tRNA fits into P site. In step three the anticodon of an incoming tRNA pairs with the next mRNA codon at A site. Step four the amino acid on the tRNA at P site forms a peptide bond with the amino acid at A site. Step five the tRNA at the P site leaves the ribosome and the ribosome shifts down by one codon. The tRNA previously at the A site is now at the P site. Step six is when protein synthesis stops when the ribosome reaches one of three stop codons on the mRNA strand.

88.

D

89.

C

90.

B

91.

A

92.

D

93.

B

94.

A

95.

The rough endoplasmic reticulum synthesizes glycoproteins and phospholipids that are transferred into cellular organelles, inserted into the plasma membrane or secreted during exocytosis. The smooth endoplasmic reticulum synthesizes fatty acids and steroids, detoxifies harmful substances, removes phosphate groups from glucose-6-phosphate and stores and releases calcium ions that trigger contractions in muscle fibers.

96.

In receptor mediated endocytosis of ligands the first step is binding, then vesicle formation, uncoating, fusion with endosome, recycling of receptors to the plasma membrane then degradation in the lysosome.

97.

The fluid mosaic model represents the molecular arrangement of the plasma membrane as an ever moving sea of fluid lipids that contain a mosaic of many different proteins.

98.

Proteins are surrounded by a transport vesicle at the endoplasmic reticulum membrane. The vesicle goes into the cis face of the Golgi body, the proteins move through the cisternae, from cis face through to trans face. Some of the proteins will leave the last trans face in secretory vessels, membrane vessels or transport vessels and go onto other organelles in the cell.

99.

Transcription is making RNA from DNA and it occurs in the nucleus while translation is making a protein from the information in RNA and it happens in the cytosol of the cell.

100.

Some proteins, like ion channels and carrier proteins, transport substances across the membrane. Proteins act as receptors for signaling chemicals to allow communication between cells. Other proteins are enzymes. There are also linker proteins that anchor cells to other cells. Lastly, some proteins help with cell recognition, such as MHC proteins that allow our body cells to be identified as “self” by our immune system.

101.

Both are mediated, energy requiring processes moving substances against their concentration gradients. Energy obtained from hydrolysis of ATP drives primary active transport, while energy stored in an ionic concentration gradient drives secondary active transport.

102.

Mitosis is the division of nuclear contents of the cell. Mitosis is preceded by replication of DNA. During mitosis the two copies of DNA are separated into two different cells. Those two cells are identical to the original cell. Mitosis occurs in somatic cells and is necessary for growth and repair. Meiosis is the type of cell division that produces the gametes, the ova and sperm. Just as in mitosis, replication of DNA occurs before meiosis so that each chromosome is doubled. However, during meiosis, there are several differences from mitosis. During prophase I of meiosis, the homologous chromosomes synapse and may exchange portions in a process called crossing-over. By the end of meiosis I, the homologs have been separated into different cells. These new cells are called haploid because they only contain one of the two homologs. Immediately after meiosis I, another round of division occurs and separates the sister chromatids in each cell. At the end of meiosis II, there are four cells. Each of those cells contains just 1 copy of each chromosome.