Chapter 2

Question 1

what 3 elements make up a chromosome

Answer 1

centromere, pair of telomeres, and origin of replication

Question 2

centromere

Answer 2

constricted region on the chromosome, serves as attachment point for spindle microtubules

Question 3

what are four types of chromosome?

Answer 3

metacentric, submetacentric, acrocentric, and telocentric

Question 4

what are telomeres

Answer 4

specific DNA sequence located at the tip of chromosome and protect and stabilize chromosome ends and stabilize it

Question 5

origin of replication

Answer 5

sites where DNA synthesis begins

Question 6

what happens to begin cell division?

Answer 6

chromosomes replicates and make a copy of itself (sister chromatids) and hold together at chromosome

Question 7

what are sister chromatids?

Answer 7

identical copies made before cell division and contains one molecule of DNA

Question 8

Interphase

Answer 8

period between cell divisions in which cell grows, develops, and functions. DNA is made, RNA and proteins are being produced

Question 9

Purpose of G0 phase

Answer 9

stable and nondividing period

Question 10

G1 phase

Answer 10

cell grows and proteins for cell division are being synthesized

Question 11

G1S phase

Answer 11

Holds G1 until cell has all the enzymes and proteins necessary for replication; after, it is ready to divide

Question 12

G2 phase

Answer 12

checkpoint to make sure all of DNA is replicated

Question 13

M (mitotic) phase

Answer 13

cell division occurs; includes mitosis, process of nuclear division and cytokinesis, complete set of genetic information

Question 14

Prophase

Answer 14

• chromosomes condense and become compact
• mitotic spindle forms

Question 15

Prometaphase

Answer 15

-nuclear membrane breaks down
- spindle microtubules enter the region and are composed of subunits of a protein called tubulin

Question 16

Metaphase

Answer 16

-Chromosomes line themselves up in the metaphase plate between two centromeres
- centrioles are at opposite ends of the pole, microtubules meeting in the middle of the cell

Question 17

Anaphase

Answer 17

• connection between two sister and chromatid breaks down and the sister chromatids separate
  -chromosomes move toward end of pole
• molecular motor proteins degrade tubulin molecules and force chromosomes toward spindle poles

Question 18

Telophase

Answer 18

• after sister chromatids have separated, they are both separate chromosomes
• marked by the arrival of the chromosome at the spindle poles
• nuclear membrane reforms around each set of chromosomes, producing two separate nucleus in the cell

Question 19

Cytokinesis

Answer 19

cytoplasm divides, cell wall forms in plant cell

Question 20

Chromosome

Answer 20

single sister chromatids

Question 21

what type of chromosomes do humans have?

Answer 21

Humans have diploid (2n), and they come in matched sets (homologous chromosomes); 46 chromosomes organized into 23 chromosomes

Question 22

What is the product of the cell cycle?

Answer 22

• produces two cells that contain the same genetic material and identical with each other and with their parent cell
• creates an exact copy of each DNA molecule; two genetically identical sister chromatids
• amount of DNA doubles in the S phase

Question 23

How to determine the # of chromosomes?

Answer 23

count the number of functional centromeres

Question 24

how do you know if sister chromatids are present?

Answer 24

chromosome has replicated and the number of DNA molecules is twice the number of chromosomes

Question 25

What happens between the sister chromatids and the chromosomes during anaphase?

Answer 25

Sister chromatids separate and each has its own centromere but after cytokinesis the 8 chromosomes are distributed equally between two daughter cells, so they each contain 4 chromosomes

Question 26

what controls the separation of chromatics/chromosomes in mitosis and meiosis?

Answer 26

cohesion, a protein that holds sister chromatids together during the early part of mitosis 1 (glue)

• in anaphase II, the chromatids can separate because it isn’t protected, thus breaks down and separates in anaphase II