Inheritance Variation Flashcards
What is DNA
Contains coded information which are instructions to put organisms together .
It is made of a polymer . Its made of 2 strands coiled together in the shape of a double helix
Nucleotides
Each nucleotide consists of one sugar molecule , one phosphate molecule and one base .
Protein synthesis
DNA unwinds and unzips in the nucleus
MRNA Molecules takes a copy of the gene
MRNA leaves the nucleus through pores and goes to the ribosomes
The ribosomes reads the MRNA molecules in codons
A carrier molecule add a specific amino acid for each codon
Eventually a chain of amino acid forms .
What is an allele
An allele is a different form of gene
What is a dominant. Gene
Characteristics that are always expressed if present
Recessive alleles
Can only be expressed if there are 2 of them
What is a homozygous
A person that has 2 identical alleles
What is a heterozygous
A person who has 2 different alleles
Genetic crossing process
Key
Phenotype is the words Genotype is the letters Then sex cells Then the genetic cross Then probability Offspring phenotype Offspring genotype
What is genetic screening
Tests that discovery if the embryo has a genetic disorder
Screening advantages
Parents can decide if they would want to terminate the pregnancy
Parents can prepare if the child has a disability
They are prepared as they will be informed if the baby will be ill in the future
Disadvantages of genetic screening
Risk of miscarriage
Tests could be incorrect
Screening is expensive
Ethically and morally wrong in some opinions
What are mutations
Changes to genes that would result in different proteins from forming
What is non coding DNA
Genes can be switched off and on . They believe non coding DNA is responsible for this .
In any one cell some genes are off those that are on are said to be expressed
