EQ's Flashcards
Describe how the Human Genome Project has helped establish a classification relationship between 2 species.
- The DNA from both species is sequenced
- The DNA is then compared for similarities and differences
- The higher the number of similarities the more closely related the series
What happens to genetic material before the cell divides?
[1 mark]
It copies itself
Give three reasons why mitosis is important for organisms
[3 marks]
1) For growth
2) For repairing damaged tissues
3) For asexual reproduction
Explain how offspring are produced by sexual reproduction
[3 marks]
Two parents are involved
The male gametes and female gametes are fused in fertilisation to produce a diploid cell
The genetic information from the male and female are mixed, this leads to variety in offspring
Spider plants can reproduce asexually. Give three advantages of spider plants being able to reproduce asexually
[3 marks]
Only one parents required
More time and energy efficient
Produces many genetically identical offspring rapidly
What does a gene code for?
[1 mark]
a sequence of amino acids
Explain how protein is synthesised from a chain of bases in DNA
[3 marks]
Bases work in triplets
Each triplet of bases codes for an amino acid
A sequence of amino acids make a protein
Mutations change the structure of proteins during cell division.
What might be the effect on the protien of the changed structure?
The protein wouldn’t function properly
Outline the function of genes
[2 marks]
They code for the specific sequence of amino acids
To rpoduce specific proteins
What is meant by the term genome?
[1 mark]
The entire genetic makeup of an organism
Give one example of why it is important for scientists to understand the human genome
[2 mark]
To help them understand the genes that lead to inherited diseases so that they can develop effective treatments for them
Explain how DNA bases code for a specific chain of amino acids
[2 marks]
Each triplet base codes for a specific amino acid
The order of the bases codes for the order of the amino acids in the chain
Describe one role that non-coding DNA plays in protein synthesis
[1 mark]
Switch genes on and off
Describe the process that takes place at the site of protein synthesis to produce chains of amino acids
[3 marks]
Amino acids are brought to the ribosome
By carrier molecules
The ribosome reads the triplet bases on the mRNA gene and uses this to join together the correct amino acids in the correct order
Explain what happens to a chain of amino acids once it has been assembled
[2 marks]
The chain folds into a unique shape
Which determines its function and allows it to do its job
Outline the role of two types of protein found in the human body
[4 marks]
Enzymes
Are biological catalysts which increase the rate of chemical reactions
Hormones
Carry chemical messages around the body through the blood
also structural proteins like collagen which provide structure and support
Explain how mutations lead to a chainge in protein synthesis
[3 marks]
Mutations change the sequence of bases in a gene
The bases code for the sequence of specific amino acids in a specific protein
Change in the amino acids leads to a change in the protein
Suggest one possible effect of a mutation that changes the shape of a structural protein
[2 marks]
A mutation will causet eh structural protein to lose its strength
This means that it will not be able to proveide structure and support
Suggest one possible effect of a mutation in a gene which codes for a particular protein
[3 marks]
The mutation will change the shape of the active site
This means that the substrate will not be able ot bind to the enzyme
This means that the enzyme can no longer catalyse chemical reactions
Explain how a fertilised egg cell has the correct number of chromosomes
[2 marks]
The two haploid gametes from the male and female fuse together
So the fertilised egg has the diploid number of chromosomes
Describe the results of meiosis
[3 marks]
4
genetically non-identical
haploid cells called gametes
What happens to the cells in an embryo as it develops in order to from a whole organism?
[1 mark]
The cells differentiate into different types of cell
Give two advantages of asexual reproduction over sexual reproduction
[2 marks]
It is less time and energy consuming
It produces many offspring rapidly in favourable conditions
Explain why sexual reproduction increases chances of a population surviving
[4 marks]
Sexual reproduction produces variation in offspring
Variation allows them to adapt to changes in the environment
Individulas with favourable variations will survive and reproduce
And pass the gene onto future generations
Give one way you can tell that the allele for a gene is not dominant
[1 mark]
Carriers of the disease do not have the disease
Explain how evolution occurs by natural selection
[4 marks]
There is variation in a species due to random genetic mutations
These variations in alleles allow individuals in a species to adapt to changes in the environment
These indiviulas are then more likely to survive and reproduce
And the advantageous alleles will be passed on and inherited by their offspring
What is meant by artificial selection?
[2 marks]
Choosing the best examples of animals/plants and breeding them together
To produce the desired characterisitcs
Suggest why pure pedigree dogs are more susceptible to genetic defects
[1 marks]
There is reduced variation in the gene pool (in pure bred animals)
Describe how characterisitcs are artificially selected
[3 marks]
- Select a male and female in a population with the desired characteristics and breed them together
- Select the offspring which inherited the desired characteristics and breed them together
- Repeat the process until all the offspring have the desired characteristics
A way to protect plants is to introduce a gene into the crop plant. The gene, which is found in bacteria, produces a poison that kills the insects.
Explain how a plant is made resistant to the insects by genetic modification
[4 marks]
- Select the gene from the bacteria that produces a poison that kills insects
- Cut out and isolate the gene using enzymes
- Insert the gene into a small circle of plasmid DNA to form a recombinant plasmid
- Transfer the desired gene into the target plant at an early stage of its development so that it develops WITH the deired characteristic
Give two reasons why people may have concerns about introducing new genes into crop plants.
[2 mrks]
There will be concerns about the effects of eating the plant on HUMAN health
There will be concerns of the transferred gene getting into surrounding species in the ecosystem
Give three advantages of producing a GM crop
[3 marks]
Resistance to disease
Resistance to insect attacks
Increased crop yield
