DNA Flashcards
DNA also known as
Deoxyribose nucleic acid.
What is meant by the term DNA? Explain
Dna is a large complex molecule that carries a genetic information that determines characteristics.
What is meant by the term heredity? Explain
Heredity is the genetic passing on of features from parents to offspring
by means of genes.
Characteristics ARISE
Characteristics arise from interactions of genes and their environment.
CHROMOSOMES are composed of ?
And what is the _____ responsible for?
60% protein 40% DNA
The protein is responsible for holding
the DNA tightly packed so it can fit the
nucleus.
What gives us NON CODING DNA?
97% of DNA does not contain genes which gives us
Non Coding DNA
Two types of NON CODING DNA found
Between genes
Within genes
NON CODING DNA CAN BE USED
To prepare DNA profiles
A gene is
A gene is a section of DNA that controls the production of protein.
Genes are found
On the chromosome.
What is gene EXPRESSION?
A gene expression is the way in which
Genetic Information in a
gene is decoded in the cell
to make a protein.
The expression of genes produces
The characteristics or traits that are inherited.
A child may inherit genes for tallness but if he lacks the nutrients correct, the genes for tallness may not be
EXPRESSED
STRUCTURE OF DNA
There are only FOUR different chemicals used in DNA known as BASES and they go by their first letters.
At The Giants Causeway
Adenine
Thymine
Guanine
Cytosine
STRUCTURE OF DNA
The bases bond with eachother but each base can only bond with on other base.
A joins with
G joins with
A + T ( Adenine and Thymine)
G + C ( Guanine and Cytosine)
STRUCTURE OF DNA
The DNA molecule is made
Is made by two strands
STRUCTURE OF DNA
The strands are held
Together by the complementary bases
Double stranded DNA is
Twisted to form a spiral structure
THE GENETIC CODE IS
The genetic code is the sequence of
bases in DNA that produce the
instruction for a cell. ( RNA ) to from a protein.
How many amino acids in combinations of what are needed to make what?
Up to 20 different amino acids in
combinations of 100s and 1000s are needed to make protein.
Genes carry and they do it by using
Genes carry codes for amino acids and they do it by using a sequence of three bases.
A group of amino acids make
Group of amino acids make a protein
C A A =
CGA =
CAA IS VALINE
CGA IS ALINE
What are the 3 BASE SEQUENCES called
TRIPLETS or CODON
A gene consists of long stretch…
A gene consists of long stretch triplets
that code for a specific sequence of
amino acids which produces a protein.
REPLICATION OF DNA TAKES PLACE
In the nucleus during Interphase
REPLICATION OF DNA
ONE : At the end of mitosis
At the end of mitosis each new cell has single strand chromosomes.
REPLICATION OF DNA
TWO : Before these new cells divide again
Before these new cells divide again the chromosomes must produce an exact copy of itself
REPLICATION OF DNA
THREE : What does this mean?
This means the single stranded chromosomes become double stranded.
MECHANISM OF DNA REPLICATION / PROCESS.
One :
The double helix unwinds.
MECHANISM OF DNA REPLICATION / PROCESS.
Two :
A enzyme breaks the bonds between the base pairs.
MECHANISM OF DNA REPLICATION / PROCESS.
Three :
The two strands of the double helix separate.
MECHANISM OF DNA REPLICATION / PROCESS.
Four :
DNA bases that are present in the cytoplasm enter the nucleus.
MECHANISM OF DNA REPLICATION / PROCESS.
Five :
Incoming bases attach to exposed complentary bases.
MECHANISM OF DNA REPLICATION / PROCESS.
Six :
Each side of the dna molecule acts as a template for the new DNA formed.
MECHANISM OF DNA REPLICATION / PROCESS.
Seven :
Each new double strands rewinds to form a double helix.
DNA DOUBLE HELIX is HALF and HALF
Half new DNA and half original DNA
Each new double helix is identical…
Identical to the original DNA
SIGNIFICANCE OF DNA REPLICATION
Dna is able to produce the exact copies of itself.
Same sequence of bases as the original.
What is a DNA PROFILE?
A DNA profile (or genetic fingerprint) is a unique pattern of bands of DNA from a person’s cell.
These bands can distinguish one person’s DNA from another person’s.
- DNA PROFILES ARE OBTAINED BY :
The DNA is released from cells.
These bands can distinguish one person’s DNA from another person’s.
2 DNA PROFILES ARE OBTAINED BY :
DNA is cut into fragments of different lengths using RESTRICTION ENZYMES.
These bands can distinguish one person’s DNA from another person’s.
3 DNA PROFILES ARE OBTAINED BY :
The DNA fragments are separated according to their size.
These bands can distinguish one person’s DNA from another person’s.
4 DNA PROFILES ARE OBTAINED BY :
The patterns produced by the fragments are compared or analysed.
DNA PROFILING STEPS IN DETAIL
THREE : GEL ELECTROPHORESIS PROCESS.
- DNA fragments placed in a glass tank with sugar based gel.
- An electric current is applied with the gel.
- Current draws the negatively charged DNA on one end of gel.
- DNA fragments move faster than larger.
- Results recorded by taking a photographic copy.
APPLICATION OF DNA.
TWO ADVANTAGES.
Establish whether biological tissue at a crime scene matches or doesn’t match a suspect.
Determine whether a person is or not the parent of a child.
What makes a child the father of his son if he takes a DNA test?
If all the BANDS in the child’s profile match the mother and father bands.
What makes a man not the father of his son if he took a DNA test?
If some of the bands match SOME of the mother but the rest do not match the father.
GENETIC SCREENING.
DNA Replication does not always happen that way it should, what does this result in?
If DNA replication does not happen the way it should which results in altered or abnormal genes.
GENETIC SCREENING
As a result of abnormal and altered genes. What does this mean for the person?
Those genes wont carry the correct code for intended protein.
This causes severe effects on person who inherits such genes.
Genetic Screening means….
Means that a persons DNA can be tested to show the presence of abnormal or altered genes.
GENETIC SCREENING can be carried out in two ways :
Adult screening.
Foetal screening.
ADULT SCREENING.
Screening is carried out on adults who do not suffer from a genetic disorder but may carry a defective gene.
FOETAL SCREENING is…
Cells removed from embryo can be tested to detect if the embryo or foetus has any genetic disorders.
