1.1 DNA Flashcards
What does DNA stand for?
Deoxyribonucleic acid
Where is DNA found? (3)
- in the chromatin network of the nucleus
- In mitochondria
- in chloroplast
- in cytoplasm of prokaryotes
What is extra nuclear DNA?
It is DNA that is outside of the nucleus of the cell
Name the three functions of DNA
DNA
- makes up genes which carry heriditary information
- Contains coded information for protein synthesis
- Can replicate itself
Name 3 physical aspects of DNA
- It is a large molecule
- Is shaped as a double HELIX
- Monomers are nucleotides
Draw a stick diagram of DNA
Name the following monomer and what each shape represents
NUCLEOTIDE
C: phosphate
P: deoxyribose sugar
R: nitrogenous base
How many rings do purines have?
2
How many rings do pyrimidines have?
1
Name two purines
Adenine
Guanine
Name two pyrimidines
Thymine
Cytosine
Name the four nitrogenous bases and state which one pairs with each
Adenine & thymine
Guanine & cytosine
- Nucleotide
- Phosphate
- Deoxyribose
- Weak Hydrogen Bonds
- Weak Hydrogen Bonds
- (Thymine)
- Adenine
- Cytosine
- Guanine
During which phase of the cell cycle does DNA replication occour?
During interphase of the cell cycle
Where does DNA replication take place?
In the nucleus of a cell
Name the enzymes involved in DNA replication
- HELICASE : unzipping
- DNA polymerase : pairing of bases
Explain what happens in the first step of DNA replication
- the double helix unwided itself
- DNA unzips as hydrogen bonds are broken by enzyme helicase
Explain what happens in the second step of DNA replication
Free nucleotides in cytoplasm match their exposed base partners
- because pairing is complementary which ensure that new DNA formed is the same as the original one
Explain what happens in the third step of DNA replication
Two daughter DNA molecules
- twist to form a double helix
- then winds itself around histones
- forming a chromosome
What is the significance od DNA replication?
- through this process, DNA is able to produce a copy of itsef
- and this ensures that genetic code is passed down to each daughter cell
Explain DNA replication (10)
define DNA PROFILE
An individual’s unique data of fragments separated by electrophoresis
How is DNA profile made? (5)
- Sample is collected
- DNA is extracted from cell
- Restrition enzymes cut the beginning and end of eache separated sequence
- Large nypumbers of sample are made through DNA amplification
- DNA fragments are separated and detected uding gel electrophoresis
Uses of DNA profiling (6)
- Forensics
- Personal identification
- Paternity testing
- Identifying casualties
- Diagnisis of inherited diseases
- Developing cures for inherited disorders
Why is the controversy against DNA profiling?
- People consider it to be a invation of privacy
- Tests are not always accurate
- Tests could have been manipulated
