Cell division - 2

Question 1

What are chromosomes

Answer 1

Each chromosome is 1
molecule of DNA which is
wrapped around histone
proteins

Question 2

What is a gene

Answer 2

A gene is a section of DNA
that codes for a protein

Question 3

What are the stages in the cell cycle

Answer 3

Mitosis
Cytokinesis
G1
S
G2

Question 4

What happens in Mitosis

Answer 4

Nuclear divison

Question 5

What happens in cytokinesis

Answer 5

Cell division
division of the cytoplasm

Question 6

What happens in G1

Answer 6

Biosynthesis
Protein synthesis
organelles replicated
Error checking

Question 7

What happens in stage S of the cell cycle

Answer 7

Synthesis
DNA replication

Question 8

What happens in G2

Answer 8

Continued cell growth
Proteins needed for cell division made
DNA checked for errors

Question 9

What happens at G1 checkpoint

Answer 9

Checks for:
- cell size
- nutrients
- growth factors
- DNA damage

Question 10

What happens at G2 checkpoint

Answer 10

Checks for:
- DNA damage
- DNA replication completeness

Question 11

What happens at the spindle checkpoint

Answer 11

Checks for:
- chromosome attachment to spindle metaphase plate

Question 12

why do organisms use mitosis

Answer 12

Growth of an organism
Repair of tissues
Asexual reproduction

Question 13

What are the 4 stages of mitosis

Answer 13

Prophase (Preparation)
Metaphase (Middle)
Anaphase (Apart)
telophase (Telophase)

Question 14

What happens during prophase

Answer 14

Chromosomes condense
Centrioles move to opposite ends of cell
spindle fibres start to form
nuclear envelope breaks down

Question 15

What happens during metaphase

Answer 15

Chromosomes line up along the middle of the
cell
Chromosomes attached to spindle by their
centromere
Metaphase checkpoint

Question 16

What happens during anaphase

Answer 16

Centromeres divide, separating sister
chromatids
Spindles contract, pulling chromatids to
opposite ends of the cell - centromere first

Question 17

What happens during telophase

Answer 17

Chromatids reach opposite ends of cell and
uncoil – now chromosomes
Two nuclear envelopes form
Two nuclei form

Question 18

What is the difference in mitosis between plants and animals

Answer 18

Plants have no centrioles where as animals do

In plants cytokinesis starts with formation of cell plate where as in animals cytokinesis starts outside

Only meristem undergoes mitosis where as most animal cells undergo mitosis

Question 19

What are alleles

Answer 19

Different versions of the same gene

Question 20

What are the differences between mitosis and meiosis

Answer 20

Mitosis produces 2 cells, meiosis produces 4
Mitosis is one division, meiosis is two
Mitosis produces diploid cells, meiosis produces haploid cells
Mitosis produces genetically identical daughter cells, meiosis produces genetically different daughter cells

Question 21

How does meiosis lead to genetic variation?

Answer 21

During prophase I, homologous chromosomes exchange DNA, which creates genetic variation. This is called crossing-over

Independent assortment of chromosomes in metaphase I

Independent assortment of chromatids in metaphase II

Mutations