Science Genetics Flashcards
What is DNA
The molecule that carries the genetic information of your parents.
DNA determines traits.
Stored in the cells nucleus.
What are the 4 nitrogenous bases and base pairs
Adenine - Thymine
Cytosine - guanine
Amino acids make up…
Proteins which make up cells which make up tissue etc.
how many chromosomes do humans have?
humans have 46 chromosomes.
What is the DNA structure
A double helix
Inheritance
The passing down of traits via genes from one generation from the next.
What is a gene
A unit of genetic information in the DNA.
The set of instruction for building a specific protein.
What is a protein
Large molecule made up of amino acids.
built out of amino acids outside the cells nucleus in the cytoplasm.
What is RNA
RNA molecules go inside nucleus to make partial copies of DNA, much shorter.
Missing one of their sides (in half) allowing them to fit through small pores in the nucleus to get outside into cytoplasm.
What is a ribosome?
Build proteins by reading the RNA code (in the cytoplasm) three letters at a time. Suck amino acids out of surroundings and stick them together in a chain according to the RNA code.
What is a codon?
Each group of three bases that the ribosome reads.
What are the 4 nitrogenous bases and pairs in RNA?
Cytosine - guanine
uracil - adenine
The addition of a base
Insertion
The removal of a base
deletion
The replacement of a base by another
substitution (not as dangerous)
3 basic types of mutation
substitution, deletion, insertion
What is a point mutation
A change to just a single base.
What is a frameshift mutation
A change to multiple bases.
What is mitosis
Cell division for growth and repair. (PMAT)
What is interphase
The cell grows, DNA replicates and cell functions.
What are the stages of mitosis/ cell cycle
90% Interphase 10% - prophase, metaphase, anaphase, telophase.
What is a parent cell
The cell that divides.
What is a daughter cell
The two new cells are called daughter cells.
What is prophase
The cell Prepares for division - chromosomes condense and nucleus begins to break down
What is Metaphase
The chromosomes line up along the Middle of the cell.
What is anaphase
Chromosomes separate and are dragged Away from each other by spindle fibres.
what is telophase
Two nuclei form, each with its own set of identical DNA
What is Meiosis
Cell division for the purpose of egg and sperm cells.
What are gametes
Sex cells.
What are female and male sex cells called
male - sperm cells
female - egg cells
fertilization
when an egg and sperm cell fuse together.
Fertilized egg contains DNA from mother and father.
What are sex chromosomes?
Determine a person’s sex. Females have two x chromosomes, males have one x and one y chromosome.
What are homologous pairs?
Two chromosomes containing versions of the same gene.
How many cell divisions in meiosis
- cell divides once and those cells divide again to form 4 sex cells with 23 chromosomes.
What is simple inheritance?
When appearance of a trait is controlled by a single gene.
What is a dominant trait
Feature that appears when one allele is present.
What is a dominant allele
Version of a gene expressed even when only one copy is present.
What is a recessive trait
Feature that only appears when two alleles are present.
What is a recessive allele
Version of a gene that is only expressed when two copies are present.
What is a genotype
An organism’s collection of observable traits.
What is a phenotype
Pair of alleles that influence the appearance of a particular trait.
homozygous
A genotype where both alleles are the same
heterozygous
A genotype where both alleles are different.
What is a punnet square
A diagram to predict the outcome of the genetic cross between two organisms.
What is a pedigree
A family tree that show how a trait is passed down from one generation to the next.
What do the symbols mean in a pedigree
Square - male
circle - female
line between - mating partners
if coloured in - presence of trait
if left blank - no trait
