revision sheet heredity

Question 1

outline mitosis

Answer 1

• IPMAT
• Interphase is the growth phase and dna replication phase
• Prophase spindle fibers start to form at eaither end of the poles the chromosomes become visible
• Metaphase the chromosome line up along the equator single file
• Anaphase spindle fibers attache to centromeres and begin to pull them to either poles
• Telophase 2 nuclear membranes form
• Cytokinesis the division of the cytoplasm to create 2 new cells

Question 2

outline binary fission

Answer 2

• DNA replication where each copy attatches to a part of the cell membrane then 2 sides of the cell begin to pull apart creating a cleavage then they divide into two separate cells

Question 3

outline meiosis

Answer 3

• IPMAT IPMAT2
• The process of a single cell dividing twice to produce 4 daughter cells
• Due to meiosis being with games thers twice as many chromosome to begin (diploid 46) then during 2 division phase turns into a haploid 23

Question 4

outline what fertilisation is

Answer 4

• is the process of sperm and ovum fusing together to create a zygote

Question 5

draw and label the structure of a chromosome

Answer 5

centromere, chromotids, genes

Question 6

where can dna be found

Answer 6

in the nucleus and in some mitochondria

Question 7

what are the 2 steps in making a protein

Answer 7

trascription and translation

Question 8

decribe transcription

Answer 8

TRANSCRIPTION
- A small section of DNA is undipped exposing nucleotide bases
- This then bgins by binding to a spromoter sequence then
RNA polyermase runs along finding spare nucleotides to make a complimantary strand.
- Once the enzyme reaches a terminator sequence it stops and dicconnects
- the mRNA sequence gets packed with a ploy a tail on the end to protect the sequence and a methalyated cap which acts as a signaling molecule to be recognised by ribosome, slicing also takes place where introns are spliced out joining extrons together

Question 9

describe translation

Answer 9

• mRNA leaves the nucleus goes through the cytoplasm and attatches to ribosome via the methalyated cap
• mRNA is then read by ribosome with tRNA having a sequence of three nucleotides called an anticodon, which can bind to specific mRNA codons. the tRNA carries the amino acid specified by the codons.
• The amino acids then all connect creating a polypeptide chain
• Once the stop codon is reached the peptide is then folded into a protein

Question 10

6. Describe examples where the environment can have an effect on the phenotypic expression of the organism.

Answer 10

• Hydrangeas phenotype can be expressed differently due to the different soil types
• Alkali soil flower petals are pink
• Acidic soil flower petals are purple

Question 11

7. Describe the different types of mutation that can occur during cell division.

Answer 11

Point mutation – is a change in DNA where only one nucleotide is altered
- Substitution
- Insertion/deletion
Chromosomal mutation- this is when mutations occur at a larger scale when chromosomes get tangled and can damage others
- Deletion- parts being removed then other seconts joining together
- Inversion- broken and turns upsidedown before repairing itself
- Duplication -inserting a section of the chromosome that already exists
- Translocation breaks off and attaches to another separate chromosome.

Question 12

8. Briefly describe the possible impacts of a point mutation on the protein produced.

Answer 12

Point mutation is a much lower scale mutation as its is where the DNA is changed and only one nucleotide is altered. This means in a different amino acid produced a changeg to the termination codon or creates a new sequence.

Question 13

9. Describe the role of crossing over in creating variation within a population.

Answer 13

This is the exchange of alleles on homologous chromosomes to create unique combination. This giving the offspring new generic traits of their own therefore increasing variation within the population.

Question 14

10. Describe the role of random assortment of chromosomes in creating variation within a population.

Answer 14

This process occurs in meisis phase 1 when homologus chromosomes spread to each pole creating different combinations due to having different orientation the daughter cell the receiving unique combiantions of chromosomes those which are different from the parents.

Question 15

11. Describe the role of sexual reproduction and fertilisation in creating variation within a population.

Answer 15

During the meiosis phase crossing over and random assortment of chromosomes create unique combinations of genetic material this resulting in the zygote having aa unique set of combinations thoat both different of both parents. This creating variation which is crutial in evaluation of a species as genetic variation is created which is also important for the adaptions of populations and changing environments.

Question 16

13. Describe sex-linked recessive patterns of inheritance and complete problems using punnett squares

Answer 16

If a female carries a recessive allele on one of her X chromosomes, she will be a carrier of the trait, but will not express it because the other X chromosome will usually have a dominant allele. However, if a male inherits the recessive allele on his X chromosome, he will express the trait because he has no other X chromosome to counteract it.

Question 17

14. Describe incomplete and codominant patterns of inheritance and complete problems using punnett square

Answer 17

Incomplete dominance when two of the allels are observed but are blended together for example a red and white flower creating pink
Co dominance when bothe allels are observed in the organisms roan cows (red and white spotty)

Question 18

example of multiallic patterns of inheritance

Answer 18

blood groups

Question 19

outline the process of gel electrophoresis

Answer 19

• DNA is cut up using restriction enzymes
• florescent dye is added to samples
• samples are added to the wells in the gels at the neg electrode end
• electricty runs through gel and neg charged dna is attraced to the pos electrode (smallest fragments moving the furthest)
• dna is viewed under a light causing it to flouresce
• now scientists can estimate the size of the fragments by comparing them to the samples of the known sized one. The dna that moved the furthest being the smallest and the ones that didn’t travl far being the largest

Question 20

18. Describe how gel electrophoresis is used for DNA profiling.

Answer 20

This technique is commonly used in DNA profiling to separate and visualize DNA fragments based on their size. DNA profiling is a process used to identify individuals by analyzing their DNA.
can be used to compare base sequences
dna identification
monitoring biodiversity and breeding programmes

Question 21

describe DNA sequencing

Answer 21

free dna bases, dna polymerase, primers, terminator bases are mixed
1. heated to 96deg and denatures dna
2. lower to 50 binding primer to dna
3. 60deg dna plymerase adds bases until terminator base
heated to 96 to separate and repeat this process till there are many then they go through gel electrophoresis
the lasers fluoresces coloured tags as they reach end of gel and camera records the colour, the colour is the converted to the corrosonding letter.

Question 22

describe the process of pcr

Answer 22

polymerase chain reaction is used for dna amplification for example at a crime scene where theres only small parts of dna they wuld use pcr to smplify this.

Denatured by heating to 96deg to break apart dna
- annealing- then cooling to 50-60 deg and primers are added to create complimentary stands
- synthesis dna (taqpolymerase) is added which is from bacteria what lives in hot springs so will not denature under the heat. and heated to 72 deg and binds free nucleotides together to make new sections

Question 23

explain how a GMO is produced

Answer 23

a gene will be inserted into a vector (agrobacterium ora virus) which ten cariies this gene and can be inserted into a plant or animal in hope the gene will incorporated into the host DNA and then expressed in the host.

Question 24

what are restriction enzymes

Answer 24

These are enzymes taken from bacteria that cut dna at the recognition site then these section of dna are removed

Question 25

23. What is ligation and what enzymes cause it?

Answer 25

Dna ligase is the enzyme that is responsible for ligation this refers to the splicing of dna strands together.

Question 26

Describe using named examples some applications of recombinant DNA technology in:
 agriculture

Answer 26

• Round up ready crops being resistant to the herbicide round up ready or the chemical glyphospate.
• AquaAdvantage in salmon where they reach their market size in just 18moht sinstead of 3 years

Question 27

24. Describe using named examples some applications of recombinant DNA technology in:
    environmental conservation

Answer 27

bioremiation- the production of GMO bacteria that can break down oil spills in the ocean

control feral pests a gene has been addedand isolated to a virus in rabits to block fertilisation

Question 28

25. Describe using named examples some applications of DNA identification technology in:
    agriculture

Answer 28

agriculture
- DNA profiling has been used to see what crops have a a specific gene. This can be disease resistance, has a faster growth rate, has a larger production and quality yield or has tolerance to adverse conditions

Question 29

25. Describe using named examples some applications of DNA identification technology in:
    environmental conservation

Answer 29

in environmental conservation DNA sequencing and profiling is used to
- Monitor endangered species and allow for quarentine to limit spread of illgal imported goods such as specif types of meat.

dna proficling also allows scientist in breeding programmes to understand which animals they should breed to increase biodiversity