Topic 6 Flashcards
(32 cards)
What is sexual reproduction?
Involves the joining of male and female sex cells (gametes)
Involves the mixing of genetic information leading to variation
What is asexual reproduction
- one parent
- no mixing of DNA
- genetically identical offspring (clones)
What is the name of the process that forms gametes?
Meiosis
Explain the steps of meiosis.
- genetic material is copied
- cell divides twice
- forms 4 gametes
- each cell has half the number of chromosomes compared to the starting cell
What is the structure of DNA
a double helix
What is a gene?
A small section of DNA that codes for a specific protein or characteristic
What are protiens made up of
Amino acids
What is the definition of genome?
The entire genetic material of an organism
What is the importance of studying the human genome?
- finding treatments for inherited disorders
- trace migration patterns
- search for which gene causes a disease
What is the definition of phenotype
- an observable characteristic
- e.g brown hair or blue eyes
What is a genotype?
A combination of alleles e.g Aa
What is a dominant allele?
An allele that is always expressed
What is meant by homozygous
Two of the same allele e,g AA
What is meant by heterozygous
Two different alleles e.g. Aa
Is polydactyl caused by a dominant or recessive allele?
Dominant
Is cystic fibrosis caused by a dominant or recessive allele?
Recessive
How many chromosomes does a human body contain
46
What are the female sex chromosomes?
XX
What are the male sex chromosomes?
XY
What is the cause of variation in a population?
Mutations
What is the effect of most mutations on phenotypes?
Most mutations have no effect on the phenotype
At what point is it determined that two species are different?
- they can no longer breed to produce fertile offspring
Explain the process of selective breeding.
- select two animals with the desired characteristic (e.g with the most muscle)
- breed these two animals together
- choose the offspring with the most desirable characteristics and breed them
- repeat across many generations resulting
How can selective breeding be useful?
- producing disease resistant crops
- producing animals who produce more meat or milk
- breeding dogs to have a gentle nature
- breeding plants to have larger flowers
