Asexual reproduction

Question 1

Define asexual reproduction.

Answer 1

Method of producing offspring that does not involve the fusion of different gametes, for example, binary fission.

Question 2

What is spore formation?

Answer 2

Fungi produce spores that are made by mitosis. They are then released into the air. If the conditions are favourable a new fungi will spawn in that place.

Question 3

What is budding?

Answer 3

When an organism generates an outgrowth organism on itself by mitosis. Once its big enough it will seperate from the parent organism and become an individual organism.

Question 4

What is binary fission?

Answer 4

A process that involves a prokaryote that duplicates its genetic material, then elongates and divides into two identical daughter cells.

Question 5

What is fragmentation?

Answer 5

When part of an organism breaks off and becomes an individual organism. The parent organisms will regenerate this missing body part.

Question 6

What is vegetative production?

Answer 6

A form of asexual reproduction of a plant. One plant is involved and the offspring is the result of one parent. The new plant is genetically identical to the parent.

Question 7

What are the steps of binary fission? (4)

Answer 7

1. replication of the circular molecule of DNA
2. attachment of the two DNA molecules to the PM
3. lengthening of the cell
4. division of the cell into two via a constriction across the middle of the cell, so that each new cell contains one circular molecule of DNA

Question 8

What are the advantages of asexual reproduction? (5)

Answer 8

• population growth occurs rapidly
• dont need to spend time looking for a mate
• dont need to spend energy making gametes
• in favourable conditions organisms can spread more quickly
• every member of species can reproduce

Question 9

What are the disadvantages of asexual reproduction? (3)

Answer 9

• doesn’t create genetic variation
• organisms have the same chance of survival
• any mutation in parent DNA will be passed on to large numbers of population through binary fission

Question 10

What is pathogenesis?

Answer 10

When an organism produces an unfertilised egg by mitosis that develops into offspring identical to the female.

Question 11

What are runners?

Answer 11

Special stems that grow over the ground. The runner grows away from the parent plant and, at alternate nodes on the runner, new buds give rise to roots, leaves, flowers and fruit

Question 12

What are cuttings?

Answer 12

Taking cuttings of shoots, roots or leaves and planting them., so that they grow into new plants.

Question 13

What are rhizomes?

Answer 13

Horizontal underground stems that can be identitfied by nodes, buds or scale like leaves.

Question 14

Where does mitosis occur in plants?

Answer 14

Meristematic tissue.

Question 15

Advantages of tissue culturing?

Answer 15

• produced in large numbers.
• plants can be cultured all year round
• produce a large number of plants that do not carry the virus

Question 16

What is tissue culturing?

Answer 16

Exposing plant tissue to a specific regimen of nutrients, hormones, and light under sterile, in vitro conditions to produce many new plants, each a clone of the original mother plant, over a very short period of time.

Question 17

What is embryo splitting?

Answer 17

Occurs when the cells of an early embryo are artificially separated, using a very fine glass needle, an embryo at an early stage of development is divided into two smaller embryos.

Question 18

What is the definition of binary fission?

Answer 18

A form of asexual reproduction in prokaryotes that involves the replication of DNA and results in two identical daughter cells.

Question 19

What is a clone?

Answer 19

A clone is a gene, cell or organism that is genetically identical to another.

Question 20

What species can repoduce both asexally and sexually?

Answer 20

Various insects eg. aphids, some crustaceans eg.fairy shrimp, algae, almost all fungal species and many plants.

Question 21

What are the types of vegetative propagation?

Answer 21

Runners, cuttings, rhizomes and suckers.

Question 22

Are the embryos produced by embryo splitting genetically identical to the parent organisms?

Answer 22

No, the two offspring are genetically identical to each other and are identical copies of the fertilised egg from which the embryo came.

Question 23

What is an enucleated cell?

Answer 23

Refers to a cell from which the nucleus has been removed.

Question 24

What is somatic cell nuclear transfer?

Answer 24

A technique where the nucleus of a somatic cell is transferred to an enucleated egg. Once inside the egg, the somatic nucleus is reprogrammed by egg cytoplasmic factors to become a zygote nucleus. It will then develop into an organism.

Question 25

What are the steps of somatic cell nuclear transfer?

Answer 25

1. obtaining the nucleus from a somatic cell of an adult animal - ‘donor’ nucleus
2. removing the nucleus from an unfertilised egg cell- nucleated egg cell
3. transferring the donor nucleus into the enucleated egg cell
4. culturing the egg cell with its donor nucleus until it starts embryonic development
5. transferring the developing embryo into the uterus of a surrogate animal where it completes development.

Question 26

What are the issues associated with cloning?

Answer 26

• inefficiency
• expensive
• health and well being of clones’ suffer from diseases, die early age
• unethical due to religious and ethical grounds
• degree of uncertainty

Question 27

What are the benefits of cloning?

Answer 27

• can produce genetically identical offspring with desired characteristics
• can increase production rate of normally slow reproducing organisms