inheritance

Question 1

polygenic inheritance

Answer 1

genotype and phenotype determined by multiple genes, resulting in continuous variation

Question 2

meiosis

Answer 2

produces gametes
non genetically identical cells, allows for variation
4 haploid cells

Question 3

mitosis

Answer 3

produces 2 genetically identical cells
asexual reproduction, growth and repair, cloning
cell reproduces by splitting to form two cells with identical chromosomes
diploid cells

Question 4

transcription

Answer 4

the process by which DNA is converted into RNA and taken out the nucleus to the ribosome

Question 5

translation

Answer 5

the process of assembling a protein

Question 6

bacterial resistance

Answer 6

• bacteria can sometimes have mutations that lead to a antibiotics having less of an impact on them
• this provides a big advantage for that bacterium, meaning its more able to survive, lives longer and reproduces more
• this leads to the allele for resistance being passed on (natural selection), so it becomes more common
• makes it harder to get rid of infection

Question 7

mutation

Answer 7

rare, random change in genetics that can be inherited

Question 8

meiosis stage 1

Answer 8

• cell duplicates its DNA, one arm of every X shaped chromosome is a copy of the other

Question 9

meiosis stage 2

Answer 9

• chromosome line up in pairs in the centre of the cell- one chromosome in each pair came from the father and one from the mother

Question 10

meiosis stage 3

Answer 10

• the pairs are pulled apart, so each new cell has only one copy of each pair of chromosomes (either father or mothers). they will have a mixture of father and mothers DNA

Question 11

meiosis stage 4

Answer 11

• chromosomes line up again in the middle of cell and the arms are pulled apart, producing 4 haploid gametes- all genetically different

Question 12

mitosis stage 1

Answer 12

• cell duplicates DNA. these form X shaped chromosomes with genetically identical arms

Question 13

mitosis stage 2

Answer 13

• the chromosomes line up in the middle of the cell and cell fibres pull them apart. the two arms go to opposite ends of the cell

Question 14

mitosis stage 3

Answer 14

• membranes form around each of the sets of chromosomes, becoming the nuclei of the new cells

Question 15

formation of proteins

Answer 15

proteins are made in the cytoplasm by ribosomes.
formed by DNA, but DNA is too big too big to get out the nucleus, so its turned into mRNA in the process of transcription

Question 16

what is mRNA

Answer 16

like DNA
made up of base sequences, but shorter and single stranded
has uracil bonded to adenine instead of thymine

Question 17

transcriptions stage 1

Answer 17

• RNA polymerase binds to the section of DNA needed. it separates the strands and moves along one of the strands

Question 18

transcriptions stage 2

Answer 18

• it uses the coding DNA as a template to make mRNA by base pairing the bases present so the mRNA is complimentary to the section of DNA

Question 19

transcriptions stage 3

Answer 19

• once made, it moves out of the nucleus and binds with a ribosome

Question 20

translation stage 1

Answer 20

• the mRNA has bonded to the ribosome and amino acids are brought to the ribosome by transfer RNA (tRNA)

Question 21

translation stage 2

Answer 21

• the amino acids are assembled according to the codons (a set of three base pairs on the mRNA), so they are complimentary and match the DNA

Question 22

translation stage 3

Answer 22

• the anticodons in the tRNA are complimentary to the codons and ensure the amino acids are in the right order

Question 23

translation stage 4

Answer 23

• the amino acids are joined together by the ribosome

Question 24

menstrual cycle stage 1

Answer 24

• day 1, lining of the uterus breaks down
• FSH and LH high, oestrogen and progesterone low

Question 25

menstrual cycle stage 2

Answer 25

- day 4-14, uterus lining builds up again ready for fertilised egg - FSH decreases a little, LH starts to increase slowly, then quicker towards the end, oestrogen increases and peaks, progesterone rises slowly

Question 26

menstrual cycle stage 3

Answer 26

- day 14, and egg is released, ovulation - LH high, FSH spikes, Oestrogen higher than progesterone

Question 27

menstrual cycle stage 4

Answer 27

- day 14-28, the wall is maintained. if no egg is in the uterus lining, the cycle starts again - FSH back to highest, LH also back to starting position, progesterone peaks, platoes and falls, oestrogen constant at starting position

Question 28

allele vs gene

Answer 28

allele a variant form of a gene gene a section of DNA that codes for a protein