B6 - Genetics and Evolution Flashcards
What do these terms mean
a) DNA
DNA - The genetic material which makes up chromosomes and genes
What do these terms mean
a) Double Helix
Double Helix - the shape of DNA - 2 twisted polymers
What do these terms mean
a) Chromosome
Chromosome - A long stand on DNA. One chromosome can contain thousands of genes
What do these terms mean
a) Gene
Gene - A section of DNA coding for one characteristic . There can be hundreds of genes on one chromosome
What do these terms mean
a) Asexual reproduction
Asexual reproduction - Reproduction which only requires one organism.
Offspring are genetically identical to the parent
In sexual reproduction, why are the offspring different to the parents?
The offspring share half the DNA with each parent.
They are not genetically identical to either parent.
What are the genetic differences between men and women?
Men = XY
Women = XX
Draw a punnet square to show the inheritance of the sex chromosomes in males and females
What is genetic variation?
Give some examples
Differences caused by the inheritance of different genes
e.g. eye colour / Blood Group / ear lobes etc
What is environmental variation?
Give some examples
Environmental Variation is caused by the choices we make and the way we live our lives - we were NOT born with them
e.g. Tattoo / Scar / Piercings
What are mutations?
Mutations - Changes in DNA
These often have no effect, but can sometimes have a positive or a negative effect
In Cystic Fibrosis
a) Dominant or Recessive
b) Symptoms
c) Treatment
Cystic Fibrosis is
a) Recessive - both parents much carry and pass on the recessive gene
b) Affects the cell membranes - causing build up of mucus in the lungs
- The pancreas does not release all digestive enzymes
c) Phsiotherpy to remove mucus from the lungs (reduce chest infections)
Tablets containing enzymes are taken before eating
In Polydactyly
a) Dominant or Recessive
b) Symptoms
c) Treatment
Polydactyly is
a) Dominant - only one parent needs to pass on the gene
b) Symptoms - extra fingers and toes
c) Extra fingers can be surgically removed
Explain these terms in genetics
a) Dominant
b) Recessive
Dominant - Likely to be shown
Recessive - less likely to be shown
What does the term ‘carrier’ mean in genetics?
Someone who has the recessive gene but does not have any symptoms
A carrier does not have the symptoms but can pass the recessive gene on
Give 2 examples of how we use selective breeding in agriculture (farming)
Breeding cattle with better characteristics for producing meat e.g. larger size / more milk
Crops which are disease resistant
Breeding crops with better yields e.g. apple trees that yeild (grow) more fruit
How would you breed the whitest sheep?
Selective breeding
Take the whitest male, and whitest female and breed them together
What are the disadvanges to selective breeding?
More chance of breeding in negative characteristics along with good
Reduces the ‘gene pool’ (selection of Alleles) which can mean less immunity to disease
What is the genetic engineering?
Taking the genes from one organism and inserting them into another
e.g. human gene for insulin inserted in bacterial DNA so bacteria make insulin for treating diabetes
How is genetic enegineering used?
Genetic egineering is taking the genes from one organism and inserting them into another
e.g. human gene for insulin inserted in bacterial DNA so bacteria make insulin for treating diabetes
What are the ethical concerns surrounding genetic engineering?
- It can be hard to predict how changing an animals DNA will effect the animal
- Many genetically modified (engineered) embryos don’t survive
- Some genetically modified animals suffer from health problems
GM Crops
- Possible reduced flowers which could effect insect population
- Lack of understanding of how GM crops may affect humans when they eat them
What is the theory of evolution by natural selection?
- All organisms show variation
- Some variations give an advantage
- They are more likely to survive
- More likely to breed/reproduce
- Pass on ‘good’ genes to the offspring
- Eventally a new species evolve - evolution
