A1.2 Nucleic Acids Flashcards
What is a nucleotide?
A monomer unit of nucleic acids
What is the backbone of DNA made up of?
The backbone is formed by covalent bonds between deoxyribose and phosphate molecules
What is the meaning of complimentary base pairing?
Nitrogenous bases align with each other in a specific way; complementary bases are held together by hydrogen bonds
How is complimentary base pairing important in the replication of DNA as the genetic material?
When the two strands of a DNA molecule are separated each one is used as a template to build a new strand; Complimentary base pairing ensures that new strands of DNA have the same sequence as the original molecule.
What are the four bases found in DNA?
- Adenosine
- Thymine
- Cytosine
- Guanine
What are the four bases found in RNA?
- Adenosine
- Uracil
- Cytosine
- Guanine
How is it possible for universal DNA molecules to store varied genetic information both within species and
between species?
There are a huge number of different base sequences possible which provides variety in the genomes
Different lengths of DNA, or different sequences of the bases causes variation in the genetic information stored in a genome
Within species each organism has many genes with a lot of similarity in the DNA sequence and this gives the species it’s recognizable characteristics
There is some variation in the sequence of DNA in some genes within species creating variation in characteristics
Between species there are more differences in the DNA sequence, which gives more variation in characteristics
How did Hershey and Chase use radioactive labelling in viral bacteriophages to demonstrate that DNA is the genetic material?
Radioactive labelling allows specific molecules to be observed
Phosphorus is found in DNA but not protein
Bacteriophage DNA was labelled with radioactive phosphorus
The radioactive label showed that the DNA part of the virus entered the bacterial cell
The radioactive labelled DNA was used to make new virus particles showing that DNA was the genetic material and not protein
What is the structure of a nucleosome?
Core made from 8 histone proteins
DNA molecule wrapped twice around the core
Additional histone protein holds the core and DNA together
What are the main differences between RNA & DNA?
DNA has two antiparallel strands of nucleic acids; RNA has one strand
What is a phosphodiester bond?
The linkage between the 3’ carbon atom of one sugar molecule and the 5’ carbon atom of another
What is a gene?
A length of DNA that codes for a protein
What is a chromosome?
A length of DNA that carries specific genes in a linear sequence
Each chromosome is a linear series of genes
What is the locus?
The particular position of a gene on homologous chromosomes
Genes for a characteristic are found at the same position ona chromosome
What is an allele?
Different versions of the same gene
