Genetics Flashcards
(41 cards)
What is the nucleus and what does it contain ?
The nucleus contains the
cell’s genetic material and it
acts as the ‘brain’ of the cell.
The nucleus contains DNA.
Zoom in on the nucleus
The nucleus is
surrounded by a nuclear
envelope
Chromatin is made of
DNA, arranged as
chromosomes
What is a gene ?
A gene is a section of DNA that codes for a specific protein.
It is the unit of heredity, and may be copied and passed on to the next
generation.
What is a chromosome ?
The cell’s nucleus contains chromosomes. These are long threads of DNA, each made up of many genes.
DNA
The chemical that carries the genetic code which determines the
characteristics of a living organism
- Instructions to put an organism together and make it function - DNA codes for proteins
Structure of DNA
● It is made up of two strands coiled together
● The two strands form a ‘double helix’ shape
DNA Bases
T, thymine A, adenine G, guanine C, cytosine A and T C and G
DNA is a polymer and is made from…
DNA strands are polymers made up of lots of repeating units called ‘nucleotides’ which are monomers
What does a nucleotide contain…
Each nucleotide consists of:
One sugar molecule
One phosphate molecule
One ‘base’
How do the nucleotides affect the structure of DNA ?
They link up with other nucleotides to form a
strand.
This strand joins with another strand to form
the double-helix
What is the function of sugar and phosphate in the structure of DNA….
The sugar and phosphate molecules in the
nucleotides form a ‘backbone’ to the DNA
strands.
Is the order of the bases important?
Yes!
It determines which protein is produced
It decides the order of amino acids
What do amino acids do to from proteins ?
Amino acids join together to form proteins
The order of amino acids in a chain determines which protein is produced
What does each sequence of three bases code for ?
Each sequence of three bases codes for a
different amino acid
eg, ‘GGT’
Some parts of DNA do not code for proteins- what do you think they do?
- Switch genes on and off
- Control whether a protein is made
Genes role in protein synthesis
- Each gene codes for (tells the cell to make) a particular chain of amino acid
- Genes also determine the specific order of amino acids, which determines the
type of protein produced - Amino acids join together to make a proteins
So each small section of DNA is a small set of instructions on how to make a
specific protein…. (definition of gene)
What does this determine ?
This determines the type of cell that is produced.
Mutations
Change the sequence of DNA bases in a gene - Creation of a different form of a gene - May create a different amino acid and sequence of amino acids - Can lead to changes in the protein coded
If a protein that needs to fit another molecule (such as an enzyme) changes shape, what is the consequence of this?
Structural proteins such as collagen (a very strong
molecule) lose their strength if their shape is changed.
They become pretty useless for support and structure,
which is their function!
ADD SICKLE CELL ANEAMIA
Patients with family history of breast cancer can be
tested to see if they have the faulty BRCA gene.
If found, women can receive intervention at and
early stage to prevent the cancer from occurring at
later life.
What is a genome
A ‘genome’ is the fancy name for the complete set of genetic
material in an organism
Why do you think it is important, in medicine, to
understand the genome?
- Identify genes linked to disease
- Produce treatments for disease
What is an allele ?
Different versions of the same gene
are called alleles.
Why do you have two
different alleles ?
One from your mother
and one from your
father.
