Genetics - Key Vocab Flashcards
Cell Membrane
Controls what enters and leaves the cell
Nucleus
Contains the DNA (chromosomes)
Chromosome
A strand/piece of DNA
Cytoplasm
Where chemical reactions take place
Mitochondria
Respiration occurs here
Variation
The difference between individuals of the same species
What does DNA stand for?
Deoxyribonulceic Acid
Deoxyribonulceic Acid (DNA)
The chemical molecule in the nucleus that carries our genetic code.
DNA is arranged into long, coiled molecules called ___________.
Chromosomes.
Normal human body cells (e.g skin cell) have __ chromosomes, or __ pairs.
- 46
- 23
_____ ___ _____ (sperm and egg) have half the amount of chromosomes that normal human body cells have.
Human sex cells
Human sex cells have __ chromosomes.
23
Genetic material is stored in the ______ of all cells. This material is called ___. It contains information needed to make an organism.
- nucleus
- DNA
DNA is arranged into strands called ___________.
Chromosomes
You have __ chromosomes in each cell, arranged into 23 _____.
- 46
- pairs
Half the chromosomes come from the ___, and half from the dad.
mum
What are genes?
Along the length of each chromosome there are coding regions called genes.
A gene is a _______ __ _ __________ that codes for a particular characteristic.
- section of a chromosome
A gene is a section of a chromosome that codes for a __________ ______________.
- particular characteristic
For each gene, we inherit ___ _____ of the gene (one from our mother, one from our father).
- two forms
Each form of the gene is called an ______.
- allele
What is an allele?
An allele is a different form a gene.
Alleles are ________ or _________.
- dominant
- recessive
Dominant alleles are always expressed even if only one of the alleles is dominant.
e.g. BB or Bb
Recessive alleles are only expressed if there are 2 recessive alleles.
e.g. bb
A person has two alleles for hair colour - one brown and one blonde. What colour hair will they have?
Brown hair colour as it is the dominant one.
If an individual has 2 identical alleles (e.g. BB, tt) for a characteristic (e.g. two blue eyes alleles) these are called __________ _______.
- homozygous alleles
If an individual has 2 different alleles (e.g. Bb, Tt) for a characteristic (e.g. a blue allele and a brown allele) these are called ____________ _______.
- heteozygous alleles
Genotype
this describes the alleles of an individual e.g., BB, Tt, ss
Phenotype
This describes the physical appearance of an individual e.g. Brown eyes, Tall, curly hair
Gamete
Sex cell
An allele that controls a characteristic when it is present on only one of the chromosomes.
Dominant Allele
An allele that controls a characteristic only if the dominant allele is not present.
Recessive Allele
