Genetics Flashcards
(24 cards)
What is egestion?
Egestion is the removal of undigested food.
What is excretion?
Excretion is the removal of waste products from the body.
Who discovered DNA’s structure?
Dr. Watson and Dr. Crick.
What type of structure does DNA have?
A double helix structure.
What is a double helix like?
A double helix is like a ladder that has been twisted.
How many pairs of chromosomes does a human have?
23 pairs of chromosomes.
How many chromosomes does a human have?
A human has 46 chromosomes.
What is mitosis?
Mitosis is the process by which cells separate into two identical cells and where the chromosome number remains exactly the same.
What is DNA?
DNA is a long molecule which carries information needed by the cell.
What is a chromosome?
A chromosome is a structure containing tightly coiled molecules of DNA.
What is a gene?
A gene is a section of a chromosome which codes for a particular characteristic.
Why do we need new cells?
To promote growth and replace dying cells.
What is meiosis?
A type of cell division that halves the chromosome number. Meiosis makes sex cells.
What is an allele?
A variant of a gene, either dominant or recessive.
What is the genotype?
The type of gene.
What is the phenotype?
The physical appearance.
Why do genes have two alleles?
Because chromosomes come in pairs.
What are alleles that are expressed called?
Alleles that are shown are called dominant.
What are alleles that are not expressed called?
Alleles that are not shown are called recessive.
What is the genotype eg. BB called?
Homozygous dominant.
What is the genotype eg. Bb called?
Heterozygous.
What is the genotype eg. bb called?
Homozygous recessive.
What are two examples of sex linked inherited characteristics?
- Haemophilia
2. Red-green colour blindness
Why is variation important?
It helps to ensure the survival of a species.
