Genetics Flashcards
What are gametes
Sperm and egg cells
What does haploid mean
Contains half the number of chromosomes of normal cells
What type of cell are gametes
Haploid
How does the zygote develop into an embryo
Mitosis
What does meiosis produce
4 haploid daughter cells - genetically different Gametes
What are DNA strands
Polymers made up of lots of repeating nucleotides
What does each nucleotide consist of
One sugar molecule and one phosphate molecule and one base
What does the sugar molecule in a nucleotide do
Forms a backbone to the DNA strands
What structure does a dna molecule have
2 strands coiled together in the shape of a double helix
What base pairs match
A and T, G and C
What are the base pairs joined by
Weak hydrogen bonds
What are chromosomes
Long cooked up molecules of dna
Where are chromosomes found in eukaryotic cells
Nucleus
What is a gene
A section of dna on a chromosome that codes for a particular protein
What is an organisms genome made up of
All an organisms dna
Steps to how dna is extracted from fruit cells
1) mash up the fruit and put in a beaker containing detergent and salt and mix
2) filter the mixture to get rid of froth and insoluble bits of cell out
3) gently add some ice cold ethanol to the mix
4) dna will start to come out of the solution as it’s not soluble in cold ethanol, it will be a stringy white precipitate that can be carefully fished out with a rod
What does the detergent do in extracting dna from fruit
Breaks down the cell membranes to released dna
Function of salt in extracting dna from fruit cells
Makes the dna stick together
What are characteristic controlled by
Different genes
What are alleles
Different versions of genes
How many alleles of every gene do u have
2 one on each chromosome pair
What does homozygous mean for a trait
Having two alleles for a particular gene that are the same
What does heterozygous for a trait mean
If it’s two alleles for a gene are different
What shows that an allele is dominant
Capital letter
What has to happen for a characteristic to be recessive
The alleles must both be recessive
What is a genotype
The combination of alleles a person has
What is your phenotype
Your characteristics
What is mono hybrid inheritance
The inheritance of a single characteristic
What does a monohybrid cross show
How recessive and dominant traits for a single characteristic are inherited
Why do females have the 23rd chromosome pair as XX
The XX combination allows female characteristics to develop
What is the chance of having a boy or girl
50:50
What 3 drawings show monohybrid inheritance
Punnet square, family pedigree, monohybrid cross
What is a family pedigree
A family tree of genetic disorders
What is genetic variation caused by
Having different alleles, sexual reproduction, having new alleles rising thru mutations, neutral mutations, the environment
What are the environmental variations in phenotype aka
Acquired characteristics
What are mutations
Changes to the base sequence of dna
What does it mean when a mutation is neutral
It doesn’t have an impact on the organism
