Lesson 2: Asexual Reproduction

Question 1

what is asexual reproduction + how does it occur

Answer 1

form of reproduction in which a new individual is produced from a single parent by cell division; occurs via cell division or mitosis

Question 1

advantages to asexual reproduction

Answer 1

• Parent organisms do not have to seek out a mate
• Specialized mating behaviors are not required
• No specialized anatomy is required

Question 2

asexual reproduction: budding

Answer 2

a new individual develops from an outgrowth on the body of an organism

Question 3

who reproduces this way (budding) explain what the process is like

Answer 3

hydra; when the conditions are favourable, hydra grows one or more extensions on the sides of their bodies- when they are large enough, the buds detach and live as new genetically identical individuals

Question 4

asexual reproduction: fragmentation

Answer 4

process in which a piece or body fragment of the parent organism develops into a mature individual

Question 5

who develops this way (fragmentation) explain the process

Answer 5

all fungi develop this way; mushrooms grow small pieces called spores, which break off and then develop into a new genetically identical mushroom

Question 6

what is mitosis

Answer 6

type of cell division that results in two daughter cells

Question 7

growth phase: interphase (how many parts in it, and what are they?)

Answer 7

this is where most of the cell life is spent; there are three parts of this phase-
G1, S, G2
- G1 phase is a cell growth phase
- S phase is DNA replication/synthesis
- G2 phase is another cell growth phase

Question 8

what happens during interphase

Answer 8

• cell grows to nearly twice in size
• nucleus makes a copy of its DNA
• organelles are also replicated

Question 8

what consists of the division stage

Answer 8

two parts; mitosis (division of the nucleus), and cytokinesis (division of the cytoplasm)

Question 9

mitosis: prophase

Answer 9

1. chromatin (DNA) condenses into chromosomes
2. centrioles move to opposite ends of the cell
3. spindle fibers form from the centrioles
4. nuclear membrane dissolves

Question 10

mitosis: metaphase

Answer 10

1. spindle fibers attach to centromeres
2. chromosomes align along the equatorial plate

Question 11

what is the equatorial plate?

Answer 11

the equator of the cell (middle line along the cell)

Question 12

mitosis: anaphase

Answer 12

1. spindle fibers shorten
2. centromere splits and pulls chromatids to opposite ends of the cell

Question 13

mitosis: telophase

Answer 13

1. chromosomes relax into chromatin
2. nuclear membrane reappears (two new nuclei are formed)
3. spindle fibers disappear

Question 14

cytokinesis

Answer 14

cytoplasm divides; in animal cells, cleavage furrows are formed and in plant cells, cell plates are formed

Question 15

kinetochore

Answer 15

protein over centromere that spindle fibres attach to

Question 16

kinetochore microtubule

Answer 16

spindle fibers attached to kinetochore

Question 17

when was the first clone created?

Answer 17

July 5th 1996- the sheep, dolly, was born

Question 18

how was dolly cloned? what was the process like?

Answer 18

an adult body cell from the sheep that were to be cloned and an unfertilized egg cell from another donor was obtained
- then, the nucleus from the cell egg was removed and an electric shock was used to fuse the adult body cell and the egg cell together
- the egg then began to divide and develop normally after being implanted into a third sheep’s uterus

Question 19

future of cloning: how is cloning not a perfected process

Answer 19

clones still do not typically survive as long and commonly suffer from health complications- dolly died prematurely of lung disease common in OLDER sheep, and also displayed premature ageing (ex: arthritis)

Question 20

future of cloning: positive implications

Answer 20

• mass production or increased yield through selective cloning of high-quality livestock and crops
• use to reproduce endangered species when captive breeding is not enough

Question 21

future of cloning: how/why is it controversial

Answer 21

• it may result in genetically vulnerable species (more susceptible to diseases, mutations, etc)
• many people feel it is unnatural or unethical

Question 22

what holds our DNA

Answer 22

our nucleus

Question 23

what are chromosomes made of

Answer 23

DNA and protein; DNA can be organized into condensed units called chromosomes

Question 24

when 46 chromosomes duplicate, how many chromosomes are there?

Answer 24

still 46 but 92 chromatids