Inheritance Flashcards
Genome
The entirety of an organism’s DNA
Genome’s function
Each gene within the genome codes for a particular sequence of amino acids. These sequences of amino acids form different types of proteins (enzymes, hormones, structural proteins like collagen)
How are chromosomes formed?
DNA double helix supercoils to form chromosomes
DNA Structure
double helix shape, complementary bases (Adenine pairs with Thymine and Guanine pairs with Cytosine), and sugar-phosphate backbone
RNA structure
- Uracil replaces Thymine
- Single strand
Protein synthesis
Process of turning a gene into a specific sequence of amino acids (that in turn makes up a specific protein)
Transcription
DNA is transcribed and an mRNA molecule is produced
Translation
mRNA is translated and an amino acid sequence is produced
Transcription role
Its role is to produce a copy of a section of DNA in the form of a strand of mRNA:
1. DNA double helix unwinds and unzips (hydrogen bonds break)
2. One strand acts as a template to make mRNA according to the complementary bases rule. e.g A-U, T-A, C-G, G-C
Translation role
Occurs in the cytoplasm and produces a chain of amino acids to form a protein:
1. mRNA molecule attaches to a ribosome
Alleles
Variations of the same gene
Phenotype
Observable characteristics such as eye colour and blood type
Genotype
The combination of alleles that control each characteristic
Dominant and recessive alleles
Dominant allele: Only needs to be inherited from on parent for the characteristic to show up on the phenotype
Recessive allele: Needs to be inherited from both parents for the characteristic to show up on the phenotype
Family Pedigrees
It helps work out the probability that someone in the family inherits a genetic disorder
Sex chromosomes
Male carry XY chromosomes and Female carry XX chromosomes. If a child inherits a Y chromosome it will become a male
Punnett Squares
It can determine the sex of a child
Mitosis
Function: Growth, repair damaged tissues, asexual reproduction
Meiosis
Function: The production of gametes and increasing genetic variation of offspring
Mitosis v Meiosis
Mitosis: Two cells produced, diploid, daughter cells are genetically identical to each other, one cell division
Meiosis: 4 cells produced, haploid, daughter cells genetically different, two cell divisions
Genetic variations
Ear lobes, eye colour, gender
Diploid cell
Two complete sets of chromosomes 23 pairs (46) chromosomes in nucleus
Haploid cell
one complete set of chromosomes, haploid cells are called gametes
Mutations
Mutations occur in the sequences of DNA bases, could lead to change in protein that the gene codes for
Theory of Natural selection
Individuals that show variation due to mutation have higher chances of survival in there environment.
Antibiotic resistance
- Random mutation occurs and a new bacterial allele codes for the antibiotic resistance
- If it survives, when you reproduce a new offspring the resistance allele will most likely be there and the antibiotic will most likely not work anymore.