3b (Inheritance) Flashcards
Genome
Entire DNA of an organism
Gene
Section of a molecule of DNA that codes for a specific protein
Nucleus of a cell contains…
Chromosomes on which genes are located
Alleles
Any two or more alternative forms of a gene
Genotype
The genetic makeup of an organism in terms of the alleles present e.g. Tt or GG
Phenotype
The physical or other feature of an organism due to its genotype and it’s environment. e.g. a tall plant or green seed
Homozygous
Having two identical alleles of a particular gene, e.g. TT or tt
Heterozygous
Having two different alleles of a particular gene, e.g. Tt, Gg
Dominant
An allele that is expressed (shows istlef) if it is present e.g. T or G
Recessive
An allele that is expressed only if there is no dominant allele present e.g. t, g
Allele
An allele is a version of a gene. One gene could have many alleles
male pair of chromosomes
XY
female pair of chromosomes
XX
Mitosis is for…
growth, repair, cloning and asexual reproduction
Mitosis (explanation)
- Chromosomes (genes) in dipliod cells clone / replicate
- They line up inside the cell
- They separate and the cell starts to divide
- Two identical daughter cells are made
Meiosis is used to produce…
Sex cells (gametes)
Meiosis (explanation)
- Chromosomes (genes) duplicate
- They pair up along the centre of the cell
- Maternal and paternal chromosomes pairs are swapped
- 2 divisions take place to make 4 haploid daughter cells
Meiosis causes…
Genetic variation
Enviromental variation such as:
climate, diets, accidents, culture, lifestyle
Genetic variation
Genes variation is due to the environment as for example if a tall parent has a child and he has potential to grow high and he doesn’t eat, he isn’t going to grow
Numer of chromosomes in diploid
46
Numer of chromosomes in haploid
23
Mutation
Rare and random change in DNA sequence coding for new alleles for gene
Darwin’s theory
- Individuals in a Species show a range of variation caused by differences in genes
- Individuals with characteristics better adapted to the environment have a higher chance of survival, allowing thme to reproduce
- These genes are passed onto their offspring, showing evolution of species via natural selection
Antibiotic resistance
- With the increase in antibiotic use, Bacteria will undergo rare and random mutations to show variation amongst bacterial population
- Bacteria that develops antibiotic-resistant gene will survive, increasing chances of survival
- This Bacteria will reproduce via binary fission to pass on this antibiotic-resistant gene to offspring that will inherit the same resistance
- Overtime, population of antibiotic-resistant Bacteria will increase, therefore making it more difficult to combat Bacterial growth
