Nucleic Acids - B7 Flashcards
How many chromosomes do humans have?
46 - 23 pairs
Why is DNA a polynucleotide?
It is made up of lots of nucleotides
What molecules make up a nucleotide?
Phosphate, deoxyribose sugar, a nitrogenous base
What type of sugar is a deoxyribose sugar?
A pentose sugar
What is the bond between the phosphate molecule and the deoxyribose sugar and how is it formed?
A phosphodiester bond, formed by condensation
What is the bond between a deoxyribose sugar and the nitrogenous base and how is it formed?
A glycosidic bond, formed by condensation
What are the four types of nitrogenous base in DNA? What are the pairs?
Adenine - Thymine
Cytosine - Guanine
What makes the base pairs complimentary?
They have a specific no. of bonds.
What type of bond is between the base pairs?
Hydrogen bonds
They are weak alone, but when there are lots together, they are strong.
How many Hydrogen bonds are between each of the base pairs?
A+T -> 2 bonds
C+G -> 3 bonds
What does it mean if DNA is anti-parrallel?
one strand goes up and one strand goes down
Why is DNA important?
It contains information of how to make polypeptide proteins. These proteins then regulate cell metabolism and behaviour
What is the name for 3 bases placed together?
A codon - 1 amino acid
What is a genome?
All of the genes in an organism
Why is the genetic code known as universal?
The same 3 bases code for the same amino acids in every living thing.
What determines an organisms characteristics?
The sequence of bases and quantity of DNA that determines the organisms characteristics.
What are the different structural components in a DNA molecule?
-sugar-phosphate backbone
-long-large molecule
-(double)helix/ coiled
-double stranded
-weak hydrogen bonds in small no.s
-base sequence
What is the function of the DNA structure phosophate-sugar backbone?
strength - protects bases
What is the function of DNA being a large/long molecule?
stores more genetic information
What is the function of the DNA structure being coiled/a double helix?
it is compact
What is the function of DNA being double stranded?
there is 1 template strand
-used in DNA replication and transcription
-if damaged or things go wrong, there is a back up
What is the function of DNA having weak hydrogen bonds in small no.s?
the bonds can be broken easily for DNA replication
What is the function of base sequences in DNA?
it is the genetic information - proteins from transcription
What is Chargaff’s Rule?
There will be:
-equal amounts if adenine and thymine
-equal amounts of cytosine and guanine
If we know the no. of adenine on one strand, we know the no. of thymine on the other strand.
What is a purine and what does it pair with?
A purine(with 2 rings) always pairs with a pyrimidine(1 ring)
Which bases are purines?
adenine and guanine
Which bases are pyrimidines?
cytosine and thymine