Y12 MW - Nucleic Acids, Structure and Function (Complete) Flashcards
What are nucleotides made up of?
Phosphate group, pentose sugar and a nitrogen-containing organic base
What are the components of a DNA nucleotide?
A phosphate group, deoxyribose and a nitrogen-containing organic base (Adenine, Thymine, Cytosine or Guanine)
What does a condensation reaction between two nucleotides form?
A phosphodiester bond
What is the structure of a DNA molecule?
A DNA molecule is a double helix with two polynucleotide chains held together by hydrogen bonds between specific complementary base pairs
What is the structure of an RNA molecule?
An RNA molecule is a relatively short polynucleotide chain
What are the components of an RNA nucleotide?
A phosphate group, ribose and an organic base (Adenine, Cytosine, Guanine and Uracil)
What is the full name of DNA?
Deoxyribonucleic acid
Which way do the two polynucleotide strands run in DNA?
Antiparallel
DNA is an ——— molecule
Information
Why are there weak hydrogen bonds between the two DNA strands?
So the DNA strands can be separated for DNA replication
Why is DNA a double helix?
To protect the bases so they are not damaged
Why is DNA a long molecule?
So it can store a lot of genetic information
Why is DNA in the shape of a helix?
So it is compact
Why does DNA have a phosphate-sugar backbone?
To provide strength for DNA
Which of the four DNA bases are purines?
Adenine and Guanine
Which of the four DNA bases are pyrimidines?
Thymine and Cytosine
What two chemicals are found within chromosomes?
Histones and DNA
Which two chemicals are found inside of a chromosome?
Histones and DNA
How is DNA packaged in eukaryotic cells?
The DNA condenses (wraps around) histones (proteins)
What kind of chemical are histones?
Proteins
What does RNA stand for?
Ribose nucleic acid
What are the differences between DNA and RNA?
The sugar present in RNA is called ribose while in DNA it is deoxyribose
In RNA the bases are Adenine, Uracil, Guanine and Cytosine while in DNA they are Adenine, Thymine, Guanine and Cytosine
RNA is single stranded while DNA is double stranded
What are the three types of RNA?
mRNA, tRNA and rRNA
What is a RNA nucleotide made up of?
A phosphate group, a ribose sugar and a base (Adenine, Uracil, Guanine or Cytosine)
What two enzymes are involved in DNA replication?
DNA helicase and DNA polymerase
What is the function of DNA helicase?
To catalyse the break down of the hydrogen bonds between the bases
What is the process of DNA replication?
DNA helicase catalyses the break down of hydrogen bonds between the bases, separating the DNA strands
Free nucleotides in the nucleoplasm become attracted to their complementary pairs
Hydrogen bonds form between the complementary base pairs
DNA polymerase catalyses the formation of phosphodiester bonds between the nucleotides
Two identical strands are created, each made up of half of the original material (semi-conservative)
What does it mean that DNA replication is semi-conservative?
Each of the two identical strands of DNA is made up of half of the original material
What provided evidence that semi-conservative replication was the process of DNA replication?
The Meselson Stahl experiment
What is the function of DNA polymerase?
An enzyme which joins nucleotides together with the formation of phosphodiester bonds
What is the main role of DNA?
To carry the genetic code which are instructions for making proteins