Transcription and translation Flashcards
how many chromosomes does each human have?
46 chromosomes
23 pairs
what is the structure of a chromosome?
DNA is tightly coiled many times around a protein called histone that supports its structure
what is a the histone protein?
histones are proteins inside the nucleus
histones are proteins that coil and structure the DNA of a nuclei into units called nucleosomes.
Protein blocks are histones
how are nucleosomes formed?
formed by histones
DNA coils twice around eight histone protein (octamer)
what is the structure of nucleosomes?
the nucleosome core is formed of two H2A-H2B dimers and a H3-H4 tetramer
what is the function of histone H1?
histone H1 holds DNA in place and anchors the nucleosome together.
what is nucleotide?
nucleotide is the building block of the DNA and RNA
what is the structure of nucleotides?
they are composed of 3 subunits
.nitrogenous base
.five carbon sugar (5C)can be ribose or deoxyribose
.1 phosphate group
what is the function of the 5C sugar and phosphate?
they give the DNA its structural element
what is the function of the nitrogenous base?
encloses genetic information
gives identity
what is the pentose ring (5C) sugar made of?
carbohydrates
what are the two types of 5C sugar?
ribose = RNA has an OH group deoxyribose = DNA has no oxygen
what are the 4 possible nitrogenous bases available in the DNA?
- Adenine
- Thymine
- guanine
- cytosine
what are the 2 types of bases?
purines
pyrimidines
what is the structure of purines?
two interlocking nitrogen - containing rings
larger space.
which nitrogenous bases are found in purines?
A and G
what is the structure of pyrimidines?
contain a single nitrogen-containing ring
less space
which nitrogenous bases are found in pyrimidines?
C and T
how are nitrogenous bases joined to the sugar?
nitrogenous bases are joined to C1 of the deoxyribose sugar
what is the function of the phosphate group?
joins 3 to 5 carbon with a phosphodiester bond
how to bind 2 nucleotides together?
to bind 2 nucleotide together we have a phosphodiester linkage
what kind of interaction is between DNA bases on different strands?
DNA bases on different strands are held together by H-bonds
what does adenine pair with?
adenine pairs with thymine by 2 hydrogen bonds
what does cytosine pair with?
cytosine pairs with guanine by 3 hydrogen bonds
why does purine bind to pyrimidine?
double ring binds to a single ring .
what is the properties of the DNA double helix
- two helical polynucleotides chains are coiled around common axis
2.the chains run in opposite direction- antiparallel
3.complementary bases are held together by hydrogen bonds
bases are at 90 degrees
the large number of hydrogen bonds provide stability of the DNA however on their own they are quite week
4.nitrogenous bases are covalently bonded to the 1 carbon of deoxyribose
how does mitochondria make its DNA?
they contain their own DNA which encode the mitochondrial proteins and some RNA
where does mitochondria contain its DNA?
contains its DNA in plasmid ring- contains genetic info for enzymes for the mitochondria such as in oxidative phosphorylation
what is the tRNA?
genes for synthesis of transfer
what is rRNA?
genes for synthesis of ribosome