Inheritance, Variation and Evolution Flashcards
What does DNA stand for?
Deoxyribonucleic acid
What is DNA?
A double stranded polymer that forms a double helix. It contains genetic material.
What is a gene?
A gene is a small section if DNA found in a chromosome
Where is DNA found?
In chromosomes
What is a genome?
A genome is the entire set of genetic material in an organism.
Scientists have worked out the human genome.
What are three benefits for understanding the human genome?
- It allows scientists to identify genes that are linked to disease
- Allow scientists to develop and understand drugs that effect genetic diseases
- The genome can be used to trace migration patterns of certain population as when people migrate they develop small changes and adaptations within their genome.
What are the four possible bases in DNA?
A,T,C,G
Which bases are complimentary to each other?
A and T
C and G
What structure is DNA?
Double Helix Structure
Where does protein synthesis take place?
Ribosomes
How are proteins made?
Proteins are made from amino acids. They are made of amino acids.
What are three uses of proteins?
Enzymes - biological catalysts that speed up reactions
Hormones - used to carry messages around the body
Structural proteins - physically strong
What is a mutation?
A mutation is the change in the sequence if DNA resulting in a genetic variant. Mutations happen continuously
What can a mutation lead to?
Mutations don’t often cause major changes only small changes in appearance however they can lead to changes in the amino acid and sometimes changes in the protein?
What do X and Y chromosomes decide?
Your sex
How many pairs of chromosomes does a human have?
23
What chromosomes makes a male and female?
Male - XY
Female - XX
What is an allele?
An allele is a different variation of the same gene
What does homozygous mean?
A gene is homozygous when it gas two alleles that are the same. A gene can be homozygous dominant or recessive
What is a recessive allele?
A allele that controls the development of a characteristic but only when two are present because it can be overruled by the dominant allele.
What is a dominant allele?
An allele that controls the development of a characteristic even when only one is present
How many alleles do you have per gene in your body?
Two - one on each chromosome pair
What does heterozygous mean?
A gene is heterozygous when it’s alleles are different
What does genotype mean?
Your genotype is the combination of alleles in a gene. This is written in letters e.g Aa or AA
What does phenotype mean?
Phenotype is the characteristic that appears from the genotype.
What is cystic Fibrosis ?
Cystic Fibrosis effects cell membranes and results in the body producing thick sticky mucus in the lungs and pancreas.
What causes Cystic Fibrosis?
Cystic fibrosis is a recessive disease and is caused by two recessive alleles. Because it is recessive people with one copy will not be effected - they are known as carriers.
What is polydactyls?
Polydactyly is a genetic disorder that cause a baby to be born with extra fingers or toes.
What causes polydactyly?
A genetic disease caused by a dominant allele so it can be inherited by just one parent.
How can embryos be screened for genetic disorders?
During IVF embryos are fertilised in a lab.
Before implantation a cell can be removed from the embryo and can be analysed genetic disorders.
