Chromosomes and Mitosis

Question 1

parts of a chromosome

Answer 1

chromatid: one “arm” of a chromosome; can also be its own chromosome
sister chromatids: identical chromatids, part of the same chromosome
centromere: where the sister chromatids are joined

Question 2

levels of chromosomes

Answer 2

DNA strand –> wrapped around histones (proteins) –> forming a coil –> forming a supercoil –> chromosome

Question 3

two types of chromosomes

Answer 3

autosome: not sex

sex chromosome: determines gender

Question 4

two types of animals

Answer 4

haploid: one copy of each chromosome type
diploid: two copies of each chromosome type

Question 5

formula for chromosome

Answer 5

Xn = Y where X is number of copies of one type of chromosome and Y is total number of chromosomes

Question 6

picture of all chromosomes in a DIVIDING cell

Answer 6

karyotype

Question 7

homologous chromosomes

Answer 7

a pair of chromosomes for the same trait, can have different alleles (found in only diploid animals)

Question 8

simplest cell division

Answer 8

binary fission: done by prokaryotes, chromosome is copied and cell divides, makes identical daughter cells, ASEXUAL reproduction

Question 9

asexual complex division

Answer 9

mitosis: done by somatic cells, makes new body cells, one diploid –> two diploid, REPAIR & REPLACE & GROWTH

Question 10

sexual division

Answer 10

meiosis: done by gonads, makes gametes, ONE diploid (gonad) –> FOUR haploids (gametes)

Question 11

interphase

Answer 11

Interphase is preparation for mitosis.
G1: gap 1 and growth; new cell grows to adult cell, performs normal functions, CAN exit to G0 (state of rest in which it is not dividing
S: synthesis; DNA is copied (allele is doubled)
G2: gap 2 (checkpoint 1); prepares for division, normal functions

Question 12

mitotic phase (1)

Answer 12

prophase: nuclear envelope dissolves, chromosomes form, centrosomes grow mitotic spindle fibers, mitotic spindle attaches to kinetochores of sister chromatids

Question 13

mitotic phase (2)

Answer 13

metaphase: mitotic spindle pulls chromosomes onto metaphase plate, line up in center

Question 14

mitotic phase (3)

Answer 14

anaphase: mitotic spindle pulls sister chromatids apart (one to each pole) using kinetochores, COMPLETE when chromatids reach centrosome poles

Question 15

mitotic phase (4)

Answer 15

telophase: centrosomes dissolve, new nuclear envelopes form, cell pinches into cleavage furrow before separating using CYTOKINESIS