Study Guide 5 (exam2)

Question 1

What is binary fission?

Answer 1

Asexual reproduction; cell divides into two identical cells

Question 2

What happens during the S phase of the cell cycle?

Answer 2

DNA replication occurs; two identical copies of each chromosome.

Question 3

What occurs during the G2 phase?

Answer 3

makes organelles, condenses chromosomes, and builds microtubules

Question 4

What is the M phase?

Answer 4

Nucleus divides and chromosomes are split into two daughter cells

Question 5

What happens during cytokinesis (C phase)?

Answer 5

Division of the cytoplasm into two daughter cells

Question 6

What is a diploid cell?

Answer 6

Two sets of chromosomes (one from each parent)

Question 7

What are homologous chromosomes?

Answer 7

Same size, shape, and genes—one from mom, one from dad

Question 8

What is the centromere?

Answer 8

Joins sister chromatids and attaches to kinetochore.

Question 9

What are sister chromatids?

Answer 9

Identical chromosome copies (S phase) joined at the centromere.

Question 10

What is a karyotype?

Answer 10

Ordered display of chromosomes to pair homologous ones

Question 11

What is monosomy?

Answer 11

One chromosome missing from a pair

Question 12

What is trisomy?

Answer 12

Three copies of a chromosome instead of two

Question 13

What is chromatin?

Answer 13

DNA + proteins that form chromosomes when not dividing

Question 14

How many nucleotides are in a typical human chromosome?

Answer 14

140 million nucleotides (1.4 x 10^8).

Question 15

What is a nucleosome?

Answer 15

Basic unit of DNA packaging, (DNA wraps around histone proteins)

Question 16

What is programmed cell death (apoptosis)?

Answer 16

Controlled process of cell death (develop/maintain healthy tissues)

Question 17

What happens at the G1 checkpoint?

Answer 17

Checks size, energy, and DNA to decide to divide, rest (G0), or delay

Question 18

What does the G2 checkpoint do?

Answer 18

Checks for DNA errors before mitosis

Question 19

What does the M checkpoint monitor?

Answer 19

Ensures proper chromosome alignment before anaphase

Question 20

What is the G0 phase?

Answer 20

Resting, non-dividing state

Question 21

What role does telomerase play in cells?

Answer 21

Prevents telomere shortening, allowing unlimited cell division

Question 22

What is cancer?

Answer 22

Uncontrolled cell division due to gene mutations

Question 23

What are the deadliest cancers in the U.S.?

Answer 23

Lung cancer, colon/rectal cancer, and breast cancer.

Question 24

What is mitosis?

Answer 24

Cell division (nonreproductive cells) —> two identical daughter cells

Question 25

What is meiosis?

Answer 25

Halves chromosome number, produces 4 (non-identical) gametes

Question 26

What is a eukaryotic chromosome?

Answer 26

DNA coiled around histones, separable during division

Question 27

What are histones?

Answer 27

Proteins that package DNA into nucleosomes

Question 28

What is interphase?

Answer 28

Cell prepares for division (G1, S, G2)

Question 29

What happens during the G1 phase?

Answer 29

Cell grows, performs functions, checks readiness for DNA replication