Term 3 - Genetics Flashcards
DNA
DEOXYRIBO NUCLEIC ACID
watson-crick model
provides the genetic code for all the protiens on organism needs to survive
Nucleotide
the building blocks of DNA. they are composed of a phosphate, pentose sugar, and nitrogenous base
Complementary base pairing
the process in which adenine will always only bind to thymine, and cytopsine will always bind to guanine in a double stranded DNA
Gene
a smaller section of the DNA strand, with a specific base sequence that codes for a specific protein
Chromosome
a length of DNA that is tightly coiled around proteins, and stored in the nucleus of the cell
Histones
the proteins around which DNA is coiled for storage
Nucleosome
made up of eight units of histones tightly coiled with DNA
Homologous chromosome
chromosomes that have matching banding patterns
Karyotyping
organises the homologous chromosomes into their specific pair
helps geneticists to determine chromosomal abnormalities
Types of chromosomes
autosomes - pairs 1-22
heterosomes - pair 23 (sex chromosome)
The Y chromosome
a fraction of the size of the X
mostly made of ‘junk DNA’
therefore women are better
Trisomy 21
(Down syndrome)
3 chromosomes of the 21st chromosomal pair
Chromatin
the ladder wrapped around histomes
4 types of nitrogenous bases
adenine
cytosine
guanine
thymine
Protein synthesis
(simply put) the process of making specialised protein from amino acids and RNA
Protein synthesis
(simply put) the process of making specialised protien from amino acids and RNA
2 STEPS
Transcription
(Step 1)
the RNA ‘unzips’ the double stranded DNA by breaking hydrogen bonds and nitrogenous bases
Translation
(Step 2)
‘triplets’ made of nucleotides match to the genetic sequence of the RNA which then creates an mRNA strand (messanger)
RNA
- base pairs: A, G, C, U
- single stranded
- creates protein via protein synthesis
mRNA
messanger RNA
carries copy of DNA code
tRNA
transfer RNA
link between mRNA and amino acids
rRNA
ribosomal RNA
Autosomal
chromosomes that do not define sex
