Genetics Flashcards
What two factors give rise to disease?
DNA (genetic) and Environmental
What is a PHENOTYPE?
Physical appearance resulting from inherited information.
Physical characteristics of a person.
What is a GENOTYPE?
Heritable genetic identity?
What predisposition do all genes control?
The predisposition to DISEASE.
What direction is DNA replicated in?
5’ -> 3’ direction.
How many copies of a genome does each person have?
Each person has 2 copies of the human genome.
What are the sex chromosomes for a male?
XY
What are the sex chromosomes for a female?
XX
What are HISTONES?
Histones are PROTEINS which DNA winds around to form chromosomes.
What is the product of cell division?
Two daughter cells are produced in cell division.
What 2 Phases is Mitosis split into?
INTERPHASE
MITOSIS
What are the 4 Phases of Interphase?
G1
S
G2
M
Describe G1 Phase.
First growth period - organelles and proteins are synthesised.
Describe S Phase.
Growth furthered.
CHROMOSOMES MAKE COPIES OF THEMSELVES.
Describe G2 Phase.
Continued growth where more proteins and organelles are synthesised.
What are HOMOLOGOUS Chromosomes?
Homologous chromosomes have the SAME:
LOCII
CENTROMERE POSITION
GENES (Alleles may be different)
SIZE
What are the two key parts of Meiosis?
(1) Homologous chromosomes LINE UP.
(2) CROSSING OVER takes place RANDOMLY.
What does CROSSING OVER enable?
Crossing over enables ALLELE RECOMBINATION.
Allows daughter cells to be genetically DIFFERENT.
What types of DNA damage exist?
- Mismatched Base
- Chemical Cross-linking
- DNA strand breaks
What is Chemical Cross-linking?
Occurs when exogenous or endogenous agents react at two different points of a DNA strand.
DNA cannot be replicated as it is blocked and leads to cell death.
What happens to damaged DNA?
Mechanisms exist which can:
- Repair DNA
- Halt cell cycle
- Apoptosis
What happens if mechanisms which repair damaged DNA are damaged themselves?
ILLNESS and DISEASE
What Mitotic stage does DNA replication take place?
S Phase.
When is it possible for DNA to be damaged?
DNA Replication.
Describe RE-ASSORTMENT.
When alleles recombine randomly resulting in genetic variation in the daughter cells produced by Mitosis.
What determines the amount of protein produced?
tsp (TeaSPoon) Transcription Splicing Processing mRNA Half life of mRNA
What is DNA transcribed to?
Pre-mRNA
What is pre-mRNA spliced to?
Mature mRNA
