Nucleic Acids Flashcards
What does DNA stand for?
Deoxyribonucleic acid
What does RNA stand for?
Ribonucleic acid
What shape is DNA?
Double helix shape
What is a nucleotide?
One phosphate group
One deoxyribose sugars
One nitrogenous base
Name two types of nitrogenous bases
Purines and pyrimidines
What nitrogenous bases are in purines?
Adenine and guanine
Name the nitrogenous bases for pyrimidines
Thymine and cystosine
What are complementary base pairs?
Two corresponding bases that are linked together
How are complementary base pairs linked together?
Hydrogen bonding
Which bases in DNA are complimentary?
Adenine and thymine
Guanine and cytosine
State the occurrences that happen in DNA replication?
1.Enzyme breaks the hydrogen bonds and the DNA double helix unwinds
2.Free DNA nucleotides link up complimentary to each exposed strand
The new DNA nucleotides are joined together by DNA polymerase
3. Each new exposed strand winds up into a double helix
What’s the importance of DNA replication?
Essential for mitosis to occur
What is DNA profiling?
Method of making a unique pattern of bands from DNA that can be distinguished from other DNA
Outline the stages involved in DNA profiling(genetic fingerprinting)?
1.The DNA is extracted from a sample of cells
2.Restriction enzymes are used to cut the DNA into restriction fragments which are different length for different people
3.The restriction fragments are separated according to size by a process called gel electrophoresis
4.the sample is viewed under ultra violent rays and analysed each pattern of bands are unique to every person
What do restriction enzymes work?
Cut DNA at specific base sequences
Outline gel electrophoresis
1.The restriction fragments are placed into a tank containing gel
2.An electric current is passed through and the DNA fragments are attracted to one end of the tank
3.The small fragments move through the gel further than the large fragments
4.Results in a series of bands
Give 2 examples of DNA profiling
Crime and medical
What is a gene?
Is a section of DNA containing the code for the formation of protein
What are proteins made of?
Amino acids
How many common amino acids are found in proteins
20
Give examples of protein
Hair,skin,muscles
Give examples of metabolic proteins
Enzymes and antibodies
How does the genetic code make protein?
1.In a gene a sequence of three nitrogenous bases is known as a triplet/codon
2.Each triplet is a gene is the instruction for a certain amino acid
3.A complete gene has many triplets and codes for many amino acids which assemble into a protein
What is a triplet/codon?
Sequence of three nitrogenous bases in a gene
What is a genome?
Complete set of genes in a cell, determines the characteristics of an organism
What is coding DNA?
DNA with genetic instructions to produce a protein
What is non-coding DNA?
DNA with the genetic instructions that does not produce a protein
What does RNA do?
Molecule that copies DNAs genetic code allowing protein to be made
What sugar does RNA have?
Sugar ribose
What sugar does DNA have?
Deoxyribose
Where is RNA found?
Cytoplasm to the ribosome
Where is DNA found?
Nucleus
What bases does RNA have?
Adenine, guanine, cytosine, uracil
What’s bases does DNA have?
Adenine, guanine,cytosine and thymine
Outline how to isolate DNA from a plant tissue
1.Chop an onion into very small pieces add salt,washing up liquid and water
2.Place beaker into a water bath for 15 minutes at 60 degrees followed by an ice bath for 5 minutes
3.Pour mixture into a food blender and blend for 3 seconds.Then pour through a coffee filter paper
4.pour into a test tube,add 4 drops of the protease enzyme, pepsin
5.Tilt test tube at an angle and carefully add freezer cold ethanol down the side
What forms on the water-ethical border?
White strands of DNA precipitate out
Why was the onion chopped up into small pieces
To increase surface area so it’s easier to break down the structure of the onion cell to release DNA
What’s the purpose of adding sodium chloride (salt)
Causes DNA to clump together
What’s the purpose in adding washing up liquid?
Breaks down the cell membrane
Why was the beaker placed in a water bath at 60 degrees and for 15 minutes?
Denature enzymes that could destroy the DNA
Why was the mixture placed in an ice bath for 5 minutes/ why not more then 15 minutes in a hot bath?
The avoid the DNA itself breaking down
Why was the mixture blended?
Shred the onion cell wall
Why was the mixture blended for no more then 3 seconds?
Avoid the DNA itself shredding
Why was the mixture filtered?
Remove unwanted parts from the mixture, therefore DNA will pass through
Why was coffee filter paper used?
Pore of a laboratory filter paper used it would take too long to filtrate, coffee filtrate paper is faster
What is a protease?
Enzyme that breaks down protein
Why were 4 drops of this enzyme added to the onion filtrate?
Break down protein around the DNA
How was the ethanol added?
Slowly down the side of the tilted test tube
Why was freezer cold ethanol added?
DNA doesn’t dissolve in freezer cold ethanol.
Why may a glass rod be used to look at DNA?
Become more visible to see
