Topic 7 (study objectives)

Question 1

genome

Answer 1

The entire genetic complement (DNA) of an organism.

Question 2

diploid

Answer 2

A cell, nucleus, or organism containing two sets of chromosomes (2n).

Question 3

haploid

Answer 3

Describes a cell, nucleus, or organism containing one set of chromosomes (n).

Question 4

homologous chromosomes

Answer 4

a pair of chromosomes of the same length with genes in the same location; diploid organisms have pairs of homologous chromosomes and the members or each pair come from different parents.

Question 5

kinetochore

Answer 5

a protein structure in the centromere of each sister chromatid that attracts and bone spindle microtubles during metaphase.

Question 6

chromatid

Answer 6

is one of the two identical halves of a chromosome that has been replicated in preparation for cell division.

Question 7

centromere

Answer 7

the centre of a chromosome where the cell’s spindle fibres attach.

Question 8

centrosome

Answer 8

a cellular structure that contributes to cell division by organizing microtubules. That contains two centrioles.

Question 9

centrioles

Answer 9

are paired barrel-shaped organelle located in a the cytoplasm of animal cells. They play a role is organizing microtubules that serve as the cell’s skeletal system. They help determine the locations of the nucleus and other organelles within the cell.

Question 10

mitosis

Answer 10

division of the nucleus.

Question 11

cytokinesis

Answer 11

division of the cell.

Question 12

What are the different parts of interphase?

Answer 12

G1, S, G2, and G0.

Question 13

What happens in G1 phase?

Answer 13

The cell grows and carries out its normal cell functions, organelles double in number, and an accumulation of materials.

Question 14

What happens in S phase?

Answer 14

DNA replication (duplicating its chromosomes).

Question 15

What happens in G2?

Answer 15

cell prepares for division, synthesis of proteins needed for division.

Question 16

What happens in G0?

Answer 16

It is the resting phase of the cell cycle.

Question 17

More info about G0 phase?

Answer 17

In G0 a cell is not actively preparing to divide, it’s just doing its job. For instance, it might conduct signals as a neuron (like the one in the drawing below) or store carbohydrates as a liver cell. G0 is a permanent state for some cells, while others may re-start division if they get the right signals.

Question 18

What are the phases of Mitosis in order?

Answer 18

Prophase, Metaphase, Anaphase, and Telophase.

Question 19

What 4 things happen in prophase?

Answer 19

1) chromosomes condense and become visible. 2) spindle fibres grow from centrioles. 3) centrioles move to opposite poles. 4) Nuclear membrane disappears.

Question 20

What 2 things happen in metaphase?

Answer 20

1) chromosomes like up along the midline. 2) spindle fibres attach to the kinetochores.

Question 21

What one main thing happens in anaphase?

Answer 21

1) spindle fibres pull sister chromatids to opposite poles of cell.

Question 22

What 3 things happen in telophase?

Answer 22

1) chromosomes unwind and become “chromatin”. 2) the nuclear envelope reforms in each daughter cell. 3) mitotic spindle disappears.

Question 23

What is the role of the spindle in cell division?

Answer 23

The spindle fibres keep chromosomes organized, aligned and assorted during the process of mitosis, lessening the occurrence of aneuploidy, or daughter cells with incomplete sets of chromosomes.

Question 24

What happens in cytokinesis in plant cells?

Answer 24

Vesicles secrete cellulose between daughter nuclei to form a new cell membrane, next a cell plate is formed until finally a cell wall is formed around each daughter nuclei and the cell are separated.

Question 25

What happens in cytokinesis in animal cells?

Answer 25

A cleavage furrow appears between daughter nuclei. A contactile ring contracts deepening the furrow. This process continues until the cell separates.

Question 26

What are the 4 important differences between cancer cells and normal cells?

Answer 26

1) lack differentiation. 2) Have abnormal nuclei. 3) Form tumours. 4) Metastasize (travel through the blood stream to start tumours).

Question 27

Where are the three check points in a cell?

Answer 27

At the beginning of G1, at the end of G2, and at the end of metaphase.

Question 28

What is apoptosis?

Answer 28

programmed cell death.

Question 29

What does check point G1 do?

Answer 29

Ensures DNA is checked for mutations, and that all chromosomes divided correctly.

Question 30

What does check point G2 do?

Answer 30

DNA is checked to ensure all chromosomes replicated correctly.

Question 31

What does check point M do?

Answer 31

Checks that all chromatids correctly attached to the spindle microtubules.