variation, evolution and genetic crosses

Question 1

what is mitosis?

Answer 1

mitosis has two identical daughter cells and is asexual reproduction. it is the process of cell division.

Question 2

what is meiosis?

Answer 2

meiosis is sexual reproduction, producing gametes (eggs and sperm). this results in four sex cells.

Question 3

women gamete’s are what?

Answer 3

eggs

Question 4

male gamete’s are what?

Answer 4

sperm

Question 5

female plant gametes?

Answer 5

eggs (stigma)

Question 6

male gametes in a plant?

Answer 6

pollen (starten)

Question 7

asexual reproduction is what?

Answer 7

when only 1 parent reproduces.

Question 8

is bacteria/fungi mitosis or meiosis?

Answer 8

mitosis = so all daughter cells will be the same.

Question 9

what are the negatives and benefits of sexual reproduction?

Answer 9

• genetically diverse population
• better protected from disease because not one is the same
• mate required

Question 10

benefits and negatives of asexual reproduction?

Answer 10

• one parent
• energy is conserved
• genetically identical

Question 11

what is a gamete

Answer 11

a sex cell

Question 12

what is gene?

Answer 12

a stretch of dna

Question 13

what is a genome?

Answer 13

bundled up dna

Question 14

what is an allele?

Answer 14

each copy of a gene.

Question 15

a dominant gene is?

Answer 15

only one gene needed to express characteristics.

Question 16

recessive genes are what?

Answer 16

needing 2 identical recessive genes to express characteristics.

Question 17

what are homozygous genes?

Answer 17

genes are the same.

Question 18

what are heterozygous genes?

Answer 18

genes are different.

Question 19

a genotype is what?

Answer 19

the genes you have.

Question 20

a phenotype is what?

Answer 20

the characteristics you have.

Question 21

cystic fibrosis is an illness with what occuring?

Answer 21

• thick cystic mucus blocks airways

- recessive disease

Question 22

embryo screening advantages and disadvantages.

Answer 22

• healthy embryo’s planted
• saviour sibling
• embryo’s are going to be created and destroyed
• people have religious objections to it

Question 23

where are chromosomes located and how many do we have?

Answer 23

they are in the nucleus and we have 46 total, 23 in pairs.

Question 24

females in chromosomes is…

Answer 24

xx

Question 25

males in chromosomes is…

Answer 25

xy

Question 26

what effects phenotype?

Answer 26

characteristics and how you look

Question 27

protein cells are…

Answer 27

• hormones
• enzymes
• cell wall

Question 28

what is inherited/genetic variation?

Answer 28

variations inherited from parents in genes.

Question 29

what is environmental variation?

Answer 29

it’s a result of our environment.

Question 30

what does dna code for?

Answer 30

it codes for the proteins it makes by the order if four chemicals called bases. they are given the letters A, C, G and T.

Question 31

what is a zygote?

Answer 31

it is the 23 chromosomes joining at fertilisation producing a cell called a zygote. it will then become an embryo.

Question 32

what is a stem cell?

Answer 32

a stem cell is a cell that can divide to make all the different tissues in the body.

Question 33

what are the arguments for and against using embryos to treat disease?

Answer 33

• infertility and genetic disease could be treated by cloning.
• they are not true individuals and it’s not right to destroy embryos to supply stem cells.

Question 34

what is an embryonic stem cell?

Answer 34

something that can develop into any type of cell.

Question 35

what are adult stem cells?

Answer 35

ones that can develop into a limited range of cell types.

Question 36

what are the types of cloning?

Answer 36

• reproductive cloning : to make embryos for infertile couples.
• therapeutic cloning : to produce embryos that can be used to treat disease.

Question 37

what is genetic engineering?

Answer 37

moving a gene from one organism to another is genetic engineering.

Question 38

how can new genetically modified plants be made?

Answer 38

• to be more resistant go insects eating them
• can be resistant to herbicides
• can produce a higher yield

Question 39

what are the negative views for GM crops?

Answer 39

• genetic engineering is against ‘god and nature.”
• there may be long-term health problems with eating GM crops.
• pollen from GM crops may spread to wild crops.

Question 40

what are positive views for GM crops?

Answer 40

• there is more food for starving populations.

- they reduce need for harmful insecticides.

Question 41

what is gene therapy?

Answer 41

the use of generic engineering to treat genetic disorders.

Question 42

what is evolution?

Answer 42

evolution is the gradual change in a species over a long period of time.

Question 43

what did charles darwin theorise?

Answer 43

he observed that organisms show variation and are slightly different. this is the theory of selection.

Question 44

what is the natural selection of rats and bacteria?

Answer 44

rats became resistant to the rat poison warfarin.

bacteria becoming resistant to antibiotics.

Question 45

explain the natural selection of peppered moths.

Answer 45

1 - pale peppered moths camouflaged on tree bark.
2 - industrial revolution turned tree bark black with soot.
3 - peppered moth no longer camouflaged and many eaten by birds.
4 - variation by sexual reproduction produces some darker moths.
5 - dark moths reproduce even darker moths.
6 - darker moths survive as birds cannot see them against the sooty bark.
7 - soon all the peppered moths are dark black. they have evolved by natural selection to suit the new environment.

Question 46

what is the structure of a cell?

Answer 46

the cell wall is the outside, and just inside that circle there is the cell membrane. the liquid inside is a the cytoplasm, and plasmids float around with the genetic material (dna) in the centre.