Practice Genetics Flashcards
What is the molecule that genes are made up of called?
DNA
Use the words “Gene” “chromosome” and “nucleus” in a sentence that explains how they relate to each other
Chromosomes are located in the nucleus that makes up a gene
What is the process called that allows the body to make new cells and replace cells that need repair?
Mitosis
When are chromosomes only visible?
When the DNA replicates
What is the process called that makes sex cells?
Meiosis
Name of the male and female sex cells
Female = egg, Male = sperm
Cells in your body that are not sex cells are called?
Somatic cells
Chromosome pairs that have the same type and match up are called?
Homologous
Sex chromosomes of the male and female are?
Female - XX, Male - XY
Looking at a Karyotype of someone that has trisomy 21, what would you notice?
They would have 3 number 21 chromosomes
The condition that has trisomy is called?
Down Syndrome
What are telomeres?
Telomeres are caps on the tip of DNA, it helps the DNA to replicate well
How many chromosomes make up a regular human body?
46
The process of dividing the nucleus is called?
Cell division
What is the difference between a Diploid cell and a Haploid cell?
Diploid has a full set of chromosomes, Haploid only has half
Why are diploid cells also 2n cells?
They are because they create double
Meiosis creates Haploid cells, why?
Stops the doubling of chromosomes during fertilisation
Give two reasons why variation is so important in populations
Survival of species
Handles changes
What is the name of the process where chromosome material swaps over in Meiosis?
Crossing over
The stage of mitosis where the chromosomes line up at the equator and spindle fibres attach at centromere is called?
Metaphase
Whereby adenine always binds to thymine and cytosine always binds to guanine
Base pairing rule
Half the number of chromosomes in a gamete
Haploid
Adenine, thymine, cytosine + guanine (uracil in RNA)
Nitrogenous bases
Involves the joining together of male and female reproductive cells
Sexual reproduction
Thread-like structures inside the nucleus of a cell
Chromosome
Molecules made of nucleotides linked in a chain (includes RNA and DNA)
Nuclear Acid
Central part of an atom that contains DNA
Nucleus
Diagram that shows the family tree for a particular inherited characteristic
Pedigree
The ability of an organism to survive the actions or effects of a certain activity
Resistance
A trait that will only be shown if there is no dominant allele present (lower case letter)
Recessive trait
Alternative forms of a gene for a particular characteristic
Alleles
Chromosomes that don’t match
Non - homologous
Having two different for a characteristic, also know as a carrier
Heterozygous
A mutation that occurs at the level of DNA bases
Point mutation
Genetic instructions inherited from parents
Genotype
Define genotype
Cannot be seen
Define phenotype
Visible
Determined by two things
Genotype and environment
What are Alleles
Is an alternative form or expression of a gene
Heterozygous
If the two alleles for a gene are different they are heterozygous eg Bb
Homozygous
If the two alleles for a gene are the same they are homozygous
Eg BB
What is sex linked
Gene for some traits are located on the sex chromosomes are called sex linked
Complete dominance
Dominant trait makes recesssive
Co Dominance
Neither allele is dominant over the other
Characteristics of both alleles
Incomplete dominance
Mixed alleles Eg Cr Cr = red flower Cw Cw = white flower Cr Cw = pink
What are the shaded shapes on a pedigreee
Lower case for both alleles, recessive
What’s a mutation?
Errors or changes in DNA, genes or chromosomes
Somatic Mutations
Alteration to DNA that occurs in body cells
Germlime mutations
Alteration to DNA occurring in gametes
Mutagen
An agent that causes a genetic mutation (change)
Eg UV rays
Deletion
Deletion is when nucleotide is removed
Duplication
Section of DNA is doubled
Inversion
Section of DNA is reversed
Insertion
Nucleotide is added on
Substitution
A nucleotide is replaced with a different one
What are some mutations that may be harmful
Down syndrome
Advantageous - sickle cell
A disease associated with a mutation in the gene that codes for red blood cells
