T1 - cell division

Question 1

Define the term chromosome.

Answer 1

Chromosomes are structures formed by the coiling of DNA double helices in the nucleus of a cell, visible during cell division, and containing genetic information in the form of genes.

Question 2

True or False? Each chromosome carries a large number of genes.

Answer 2

True, Each chromosome carries many genes which code for many different types of protein.

Question 3

How many chromosomes do human body cells contain?

Answer 3

Human body cells contain 23 pairs of chromosomes, totaling 46 chromosomes in diploid cells (often represented as 2n).

Question 4

Why are chromosomes found in pairs in human body cells?

Answer 4

Chromosomes are found in pairs called homologous pairs. One chromosome in each pair is inherited from each parent. They carry corresponding genes, although they may have different alleles for each gene.

Question 5

How is the chromosome number in the gametes different to that of body cells?

Answer 5

Gametes (sperm and egg cells) contain the haploid number of chromosomes (n), which is half the diploid number found in body cells.

Question 6

True or False? Chromosomes are only visible during cell division.

Answer 6

True, Chromosomes condense and become visible during cell division (like mitosis or meiosis) when the DNA coils tightly to form distinct structures.

Question 7

Define the term mitosis.

Answer 7

Mitosis is nuclear division that results in the production of genetically identical cells. It is used for growth, repair, and asexual reproduction.

Question 8

True or False? Mitosis results in genetically diverse cells.

Answer 8

False, Mitosis results in genetically identical cells.

Question 9

What happens to chromosomes before mitosis?

Answer 9

Before mitosis each chromosome replicates, producing two identical copies of each chromosome; one for each of the two daughter cells.

Question 10

Why is mitosis important in the body?

Answer 10

Mitosis is important in the body to produce new cells for growth, repair of damaged tissues, and the replacement of cells.

Question 11

What is the outcome of a mitotic division?

Answer 11

A mitotic division produces two genetically identical daughter cells. The daughter cells are genetically identical to each other and to the parent cell.

Question 12

What cells are not produced by mitosis in animals and plants?

Answer 12

The gametes (i.e. sperm, egg cells, pollen and ovules) are not produced by mitosis, instead they are produced by meiosis.

Question 13

How many chromosomes are present in a human cell produced by mitosis?

Answer 13

Human cells produced by mitosis contain 23 pairs of, or 46, chromosomes.

Question 14

True or False? Mitosis is another name for the cell cycle.

Answer 14

False, Mitosis is a part of the cell cycle. The majority of the cell cycle is spent in the stage when the cell grows and DNA replicates.

Question 15

Name the three stages of the cell cycle.

Answer 15

The cell cycle is made up of cell growth, DNA replication and organelle replication, mitosis (division of the nucleus), and cytokinesis (splitting of the cytoplasm).

Question 16

True or False? Ribosome numbers increase in cells before mitosis occurs.

Answer 16

True, In order for cell division to occur successfully, the subcellular structures must be replicated. This includes ribosomes and other organelles such as mitochondria.

Question 17

Define the term stem cell.

Answer 17

A stem cell is an undifferentiated cell capable of giving rise to many more cells of the same type and from which other cells can arise from differentiation.

Question 18

True or False? Embryonic stem cells can differentiate to produce most cell types.

Answer 18

True, Embryonic stem cells can differentiate into most, or in some cases all, cell types. This enables them to form the tissues and organs needed during development.

Question 19

How can stem cells be used to treat diseases such as diabetes?

Answer 19

Stem cells could potentially treat diseases such as diabetes by replacing damaged/unhealthy cells with healthy stem cells, which can continually divide to form more healthy cells.

Question 20

What is the potential benefit of being able to use a patient’s own stem cells in medical treatment?

Answer 20

A potential benefit of being able to use a patient’s own stem cells in medical treatment is that stem cells from the same patient would not be rejected by the patient’s immune system.

Question 21

True or False? There is risk of infection when transferring lab-cultured stem cells into a patient.

Answer 21

True, Stem cells cultured in a lab can become infected. Infection can then be passed to patients during therapy.

Question 22

True or False? There are ethical issues associated with the use of embryonic stem cells in medicine.

Answer 22

True, Many have ethical concerns around the use of embryonic stem cells in medicine. These concerns are related to whether or not embryos should have human rights. Concerns include: Destruction of embryos, Embryos cannot give consent, Embryos are treated as a commodity.

Question 23

True or False? Adult stem cells have a limited capacity to differentiate.

Answer 23

True, Adult stem cells have a limited ability to differentiate; they can only give rise to a few cell types.

Question 24

Name the tissue type found in plants where stem cells are located.

Answer 24

Stem cells in plants are found in meristem tissue in the growing roots and shoots.

Question 25

What is the location in the human body of the stem cells that differentiate to form red blood cells?

Answer 25

Red blood cells differentiate from stem cells found in the bone marrow.

Question 26

How can meristem cells be used, alongside cloning, to aid plant conservation and crop development?

Answer 26

Stem cells from the meristems of plants can be cloned to quickly produce large numbers of endangered plant species and crop plants with desirable features, e.g. disease resistance.