Topic 3 Flashcards
What is transcription and protein synthesis
When RNA polymerase reaches a particular sequence of bases in the DNA it detaches and the production on pre-mRNA is complete
What are 4 bases in a DNA called
Adenine
Guanine
Cytosine
Thymine
What does Adenine go with
Thymine
What does cytosine go with
Guanine
What are animals that reproduce asexually
Amoeba, Hydra, water flees eg Daphnia
What plants reproduce asexually
Strawberry’s and clover, succulents, potatoes
What are the advantages of sexual reproduction
Produces offspring that are genetically different which is good if the environment changes so some offspring will be better suited for it
What are disadvantages of sexual reproduction
Slower than asexual reproduction
Requires 2 mates- males and female
Eggs and spermicide need to be produced, dispersed, then to fuse during fertilisation
What are the advantages of asexual reproduction
Much faster than sexual reproduction
Only 1 mate is needed
Can create lots in a short period of time
What are the disadvantages of asexual reproduction
If all offspring are genetically identical they will all be affected negatively if the environment changes
What is meiosis
It produces 4 genetically different sex cells
It allows variation to occur between individuals of the same species
2 haploid cells fusing at fertilisation to restore the diploid number
What happens in the first stage of meiosis
There are 4 separate single chromosomes in 2 pairs but in their own
Happens in stage 2 of meiosis
The single chromosomes fuse to make 2 pairs, each one has become a pair of sister chromosomes
Genome
The haploid set of chromosomes in a gamete or microorganism or in each cell of a multicellular
Polymer
A substance which had a molecular structure built up chiefly or completely from a large number of similar units bound together
What is the backbone/ spine of the 2 strands in a DNA molecule made up of
Small phosphate and sugar that had a pentagon shape
Why is a helix strand described as being double helix
A helix is a spiral structure and as DNA is 2 helixes it’s known as a double helix
In mRNA what does Uracil replace
Thymine
What does mRNA stand for
messenger
Ribose
Nucleiz
Acid
Transcription
DNA is copied into mRNA in the nucleus
mRNA is a complementary single-strand of nucleotides
mRNA moves from the nucleus into the cytoplasm
Translocation
mRNA is decoded when it attaches onto a ribosome in the cytoplasm
The mRNA codon is complementary to an anti-codon on a tRNA which has an amino acid attacked to it
The m & t matchup and their animo acids link to form a polypeptide chain, the beginning of protein
Genetic variation
A Change in a base sequence can create a change in the sequence of animo acids. If the mutations fixed a new Allen has evolved
Protein synthesis
The animo acid chain is called a polypeptide
The enzymes that attaches to DNA separates its strands: RNA polymerase
mRNA strands become attached to a ribosome which links together the substances carried by the tRNA
The mRNA strand codons match up to tRNA molecules
What do triplets do
Tell DNA when to stop and make new lines of code
