Genetics Flashcards
(43 cards)
Mendel (1872-1884)
Dichotomous traits. One form or another never in combination.
What is phenotype?
the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.
What is genotype?
the genetic constitution of an individual organism.
What is allele?
each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
What is heterozygous and homozygous?
When an individual has two of the same allele, whether dominant or recessive, they are homozygous. Heterozygous means having one each of two different alleles.
What do you call the grid of genes?
Punnet square
What is autosomal chromosome?
Any chromosome that is not sex chromosome.
How many autosomal and sex chromosomes do we have?
22 pairs of autosomal chromosome and 1 pair of sex chromosomes.
If a recessive gens is on an autosomal…
its effects will be found equally in males and females.
If recessive gene is an x chromosome…
It’s effects will be formed more often in males
What are chromosomes made of?
DNA
What are the base pairs?
Adenine Thymine
Cytosine Guanine
What is the structure of DNA?
Alpha helix- good shape allows DNA unwinds so it can replicate- Good because makes new cells or babies
Spare bases bind to complementary bases in unwound strands
What is mitosis?
Cell replicate complementary strands of DNA form new chromosomes get twice as many as you started with. Cell splits new cell as DNA you started with. Needed to make new cells or babies.
What is meiosis?
In sperm/egg cells end up with cells with one of each chromosome pair DNA still replicates left with sperm or cells when they fuse one pair of chromosome from mum and one from dad - random which pair you have.
What happens when crossing over occurs?
Sometimes in meiotic cell crossing over can occur, when chromosome line up a bit of chromosome gets swapped with another bit called chiasma official name recombinant chromatids.
What does DNA make?
Proteins
What do genes hold the instructions of? How?
To make proteins- Unwinding of the alpha double helix makes complementary strand of single stranded mRNA .
RNA- Ribonucleic acid CGAU into DNA.
Describe the process of translation…
RNA gets translated into a protein. DNA unwinds mRNA copies DNA in to AGCU single strands mRNA out of the nucleus into the cytoplasm and mRNA gets translated tRNA brings amino acid complementary base pairs on heads specific amino acids. Ribosome reads letters of three calls tRNA and ribosome then builds chain of amino acids - becomes peptide - may become more complex to secondary tertiary structure and become a protein.
What chromosome causes down syndrome? What does it cause? What percentage of genes, mRNA and protein (amyloid) does it have?
Trisomy chromosome 21 - three copies of it cause downs syndrome. Cognitive deficit. 150% of each.
RNA is a complimentary copy of one strand…
of a DNA molecule.
Briefly state the process of down syndrome in terms of genes..
Gene overexpression -> Neuropathology -> Cognitive deficit
What gene is involved in Alzheimer’s disease?
21 on Amyloid Precursor Protein (APP) there are amyloid plaques that lead to neurofibilary tangles.
What is phenylketonuria (PKU)?
Autosomal recessive gene
Single mutation
Inability to metabolise phenylalanine (an amino acid)
Results in brain damage
Caused by mutation in the gene for the hepatic enzyme phenylalanine hydroxylase (PAH) rendering it non-functional.
When PAH activity is reduced, phenylalanine accumulate and in converted into phenyl pyruvate.