3: Protein Synthesis & Cell Division Flashcards
What are proteins made of?
Proteins are the basic structural molecule of the body. They’re made up of carbon, oxygen, hydrogen and nitrogen. Atoms come together to form molecules called amino acids which create chains that make up proteins
What is the structure of proteins?
Proteins have differences in their biochemical structure determined by the amino acid polymer length and the composition and position of amino acids within the chain. This defines the three dimensional shape of a protein
How are proteins produced?
Proteins are created by protein synthesis which uses the coding from the DNA
What is DNA?
DNA is made of deoxyribose sugar and four nucleotide bases: A-T, and C-G
How is DNA involved in protein synthesis?
The amino acid sequence for every protein is held in the DNA within the chromosomes of the nucleus. This piece of DNA is called a gene and holds the code for one protein. Three DNA bases code for each amino acid eg ATC or CGA. The cell will translate the base sequence into a sequence of amino acids that makes up the protein
What is a promoter region?
A promoter region is found in every gene and regulates its activity
What is transcription?
Transcription is the first part of protein synthesis and means “to make a copy”.
What is mRNA?
DNA molecules are too large to go across the nuclear membrane so a ‘go-between’ carries the information from the DNA to the ribosome. This go-between is called messenger RNA (mRNA) add is a copy of the DNA base sequence
How does sequencing work in mRNA for protein synthesis?
The bases on the mRNA copy of the DNA are a complimentary match to the DNA code itself, except that “U” substitutes for “T”. The mRNA then exits the nucleus and travels to the ribosome
What is a codon?
A codon is a triplet of DNA bases
What is cell splicing?
Cell splicing happens before the mRNA copy leaves the nucleus: splicing edits the copy and removes sections (called introns). This has significant regulatory activity in a cell
What is translation?
Translation is the second part of protein synthesis
What happens in translation?
In translation, a piece of mRNA squeezes into the ribosome until the first of its three bases is in the centre of the ribosome
What is tRNA?
TRNA is found in the ribosomes cytoplasm
What role does tRNA have in protein synthesis?
During translation, one end of the tRNA molecule binds to one type of amino acid. The other end has a three nucleotide base triplet called an anticodon. The base sequence of the anticodon is a complimentary match to the sequence of each amino acid in mRNA
What is an anticodon?
An anticodon is found at one end of tRNA. Its base sequence is a match to the sequence of amino acid in mRNA
What are chromosomes?
There are two sets of chromosomes in every cell, making it a diploid. The full set contains 22 pairs of somatic chromosomes and a pair of sex chromosomes (XX/XY)
What is mitosis?
Mitosis is a form of continual cell division where the daughter cells are genetically identical to its parent. The daughter cell has a duplicate copy of the parent’s DNA
What are chromatids?
In S phase of mitosis, each chromosome creates a duplicate too, called a chromatid. This is passed onto the daughter cell
What is meiosis?
Meiosis is a form of cell division that produces sperm and ova, which are genetically different to their parent cell
What is the process of meiosis?
Meiosis has four steps:
- Chromosomes duplicate their DNA to form chromatids ready for division
- The chromosomes come together to form a tetrad. Crossover occurs where pieces of one chromosome swap with corresponding parts of their partner chromosome
- The cell divides to form two diploid daughter cells that are genetically different from their parent cell
- Each daughter cell divides, but the DNA is not duplicated. Each gamete receives one copy of each chromosome
What is a gamete?
A gamete is an organism’s reproductive cells. Female cells are called ova or egg cells and male cells are called sperm
What is a haploid?
A haploid is a cell with only one chromosomee
What is a diploid zygote?
A diploid zygote has characteristics of both parent cells, but isn’t genetically identical to either. It has two chromosomes
