Bio - 16.1, 16.2

Question 1

2 types of reproduction

Answer 1

1. asexual
2. sexual

Question 2

chromosomes

Answer 2

• long threads of DNA found in the nucleus of the cell
• contain sets of instruction known as genes

Question 3

asexual reproduction - facts

Answer 3

• involves one parent
• cells will divide to produce new cells that contain exactly the same genes as the parent cell (genetically identical)
• quick and efficiently produce many new organisms, all genetically identical to one another

Question 4

asexual reproduction - definition

Answer 4

• a process resulting in the production of genetically identical offspring from one parent

Question 5

asexual reproduction - advantages

Answer 5

• quicker
• only one parent is needed
• lots of offspring quickly
• genetically identical
• higher rate of success

Question 6

asexual reproduction - disadvantages

Answer 6

• no variation
• more vulnerable to disease
• no adaptation / evolution
• prone to extinction

Question 7

sexual reproduction - definition

Answer 7

a process involving the fusion of the nuclei of two gametes (sex cells) to form a zygote and the production of offspring that are genetically different from each other

Question 8

sexual reproduction - process

Answer 8

parents produce gametes => gametes join => nuclei fuse together => fertilisation => new cell => zygote => cell division => grows into a new organism

Question 9

gametes

Answer 9

• sex cell
• 1/2 the normal number of chromosomes
• nucleus fuses with the nucleus of another gamete during sexual reproduction
• 2 gametes = 1 zygote
  *eg. egg and sperm

Question 10

fertilisation

Answer 10

fusion of the nuclei of two gametes

Question 11

binary fission - definition

Answer 11

a process of bacteria dividing into 2 by splitting

Question 12

zygote

Answer 12

• a cell that is formed by the fusion of two gametes
• contains chromosomes from both parents
• any combination of genes

Question 13

sexual reproduction - advantages

Answer 13

• variation
• better survival chances
• enables natural selection
• less risk of disease wiping out all

Question 14

sexual reproduction - disadvantages

Answer 14

• slower process
• fewer offspring
• requires two parents

Question 15

difference with growth & development

Answer 15

growth = increase in size, irreversible, cell division
development = increase in complexity, formation of different cells

Question 16

diploid - definition

Answer 16

having 2 complete sets of chromosomes
*eg. zygote

Question 17

haploid - definition

Answer 17

having 1 complete set of chromosomes
*eg. gametes

Question 18

asexual, species in wild - advantages

Answer 18

• fast reproduction (quick population growth)
• only one parent (if isolated)
• identical to parents (if parent adapted well, all offspring will be too)

Question 19

asexual, species in wild - disadvantages

Answer 19

• no variation (clones)
• vulnerable to disease (if one dies, all die - same weakness)
• no evolution & adaptation (future populations cant adapt to new conditions)

Question 20

asexual, species in crops - advantages

Answer 20

• desirable traits are preserved (can produce identical crops)
• fast and reliable (doesn’t depend on pollination / seasons)
• uniformity (mature at the same time - easy harvesting)

Question 21

asexual, species in crops - disadvantages

Answer 21

• no variation (disease affects all plants)
• soil nutrients deplete faster (identical plants, identical nutrients)
• no improvements through breeding (cant develop new features to adapt)

Question 22

sexual, species in wild - advantages

Answer 22

• variations
• better adaptation (increases chances of survival in changing environments)
• natural selection & evolution (favourable traits are passed on - improves species overtime)

Question 23

sexual, species in wild - disadvantages

Answer 23

• solver process (find mate, produce offspring)
• fewer offspring (compared w asexual)
• no possible in isolation (far apart / small population)

Question 24

sexual, species in crops - advantages

Answer 24

• variation allows selective breeding (farmers can combine good traits)
• new varieties can adapt to changing condition
• can improve yield & quality over generations

Question 25

sexual, species in crops - disadvantages

Answer 25

- takes longer & more effort (pollination, seed formation, breeding) - not identical (may not have desired features) - less predictable (variation = uneven growth)