Genetics Overview Flashcards
Where is a nucleus located?
In the center of a cell
What is inside chromosomes?
Your genes
Definition of trait?
A genetically determined characteristic such as eye colour.
What is a genome?
The total collection of genes possessed by an organism
What is the double helix?
The shape which two DNA molecules form together
What is discontinuous variation?
Either/Or
e.g:
tongue rolling, free or connected earlobes
What is continuous variation?
It changes
e.g:
height, foot size, hair length
How do you get your sex?
The egg is always an x. The sperm is either an y or an x if its xy it is a boy if xx it is a girl
What is genetic variation?
The genetic difference between two individuals, for instance mutations.
What are the advantages of A-sexual reproduction?
Population can increase rapidly, only one parent needed, it is more time and energy efficient and it is faster than sexual reproduction.
What are the disadvantages of A-sexual reproduction?
No genetic variation, species only suited to one habitat and disease may effect the whole population
What are the advantages of sexual reproduction?
It produces genetic variation, the species can adapt to new environments, a disease is less likely to affect the whole population
What are the disadvantages of sexual reproduction?
It takes longer because a mate must be found, then the egg must be fertilised and then the offspring has to develop.
What is the definition of genetics?
The study of how genes and traits are passed down from generation to generation. Our genes carry lot’s of information like our health, appearance and personality.
What is a punnet square?
Used to predict the genotypes of breeding experiments
What is a cell?
The basic building blocks of all living things
What are the base pairs of a cell?
Four different bases in DNA: Adenine, Thymine, Guanine and Cytosine. These four chemicals are repeated in different patterns over and over again to make all the DNA strands.
What are ratios in a punnet square?
If your punnett square contains one YY, 2 Yy, 1 yy your genotypic ratio is 1:2:1 your phenotypic ration would be 3……. : 1……….
Can a mutation be passed on if it’s not in the gamete/sex cell?
No, a mutation must occur in the gamete for it to be able to be passed on.
Does the offspring number need to be larger or smaller for the predicted ratio to be more accurate?
Larger, with a larger number of offspring the predicted ratio will be more accurate.
What is the name for a body cell?
Somatic
If the 2 alleles are dominant the GENOTYPE is:
HOMOZYGOUS DOMINANT
If the 2 alleles are RECESSIVE the GENOTYPE IS:
HOMOZYGOUS RECESSIVE
If the 2 alleles are different the GENOTYPE is:
HETEROZYGOUS
How do you answer questions in the exam?
- Define (terms)
- Explain
How many cell divisions does Mitosis have?
1
How many cell divisions does Meiosis have?
2
What is the name for the amount of chromosomes sets in a Somatic cell?
Diploid (full set of cells) (meaning 2 sets, 1 set from each parent)
What is the name for the amount of chromosome sets in a Gamete cell
Haploid (half set of cells) (meaning 1 set)
How does sexual reproduction relate to Variation?
During sexual reproduction, meiosis occurs, leading to independent assortment and crossing over.
