Chapter 3 - Cell Protein Production Flashcards
Name some proteins found within the body
- Insulin
- Haemoglobin
- Actin ans Myosin
What is synthesis?
Synthesis is the combining of small molecules to make larger molecules
What does synthesis require?
Matter and Energy
Why is synthesis of proteins important to cell metabolism?
The synthesis of proteins is a very important part of cell metabolism because proteins make up much of the structural material of a cell, and special proteins called enzymes control the cell’s chemical reaction.
The types of proteins a cell can make is determined by…
genes
What is transcription?
Transcription is the process by which the mRNA is formed using the code in a DNA molecule
What is the first stage of transcription?
The two strands of the DNA molecule seperate and the RNA polymerase begin to make mRNA.
What is the second stage of transcription?
RNA polymerase joins nucleotides with bases that are complementary to those on the DNA template strand.
What is the third stage of transcription?
mRNA is formed with bases that are the same as the coding strand of DNA. mRNA moves into the cytoplasm through a nuclear pore.
What are introns?
Introns are non-coding sequences.
What are exons?
Exons is the base sequence that code for amino acids
What happens after the mRNA has been made?
The mRNA that has been copied will contain both introns and exons, the introns must be removed before the mRNA can be used to assemble amino acids into a protein.
What is a codon?
A codon is a sequence of three basis in the mRNA molecule that are thr code for an amino acid.
The bases of the codon are complementary to those in the template strand and the same as those in the coding strand of the DNA.
What is transcription?
Transcription is the production of a protein using the information that is coded in the mRNA molecule.
tRNA is made of …
A chain of nucleotides that pair with each other to give the molecule a characteristic shape
What is an anti-codon?
The three bases on a tRNA molecule that are the ‘mirror image’ of a codon
what is a start codon?
When a ribosome is reading the code in the mRNA, it is triggered to start joining amino acids together by the start codon.
For each bond formed between the amino acids, the energy from the breakdown of one ATP molecule is required.
What is ATP?
Adenosine Triphosphate is a molecule that stores energy for use in cell processes.
Summerise protein synthesis
Transcription
- two strands sperate
- mRNA form bases complementary to those on the DNA strand
- mRNA undergoes modicfication - inrons are removed leaving eons
- mRNA travels from the nucleus to the cytoplasm
Translation
- mRNA attaches to ribosome
- ribosome moves along the mRNA, reading the code. the start codon begins making the protein
- a tRNA with a matching anticodon brings the correct amino acid
- amino acids bond together to form the protein
What is gene expression?
Gene expression is the production of a protein using the information encoded in a gene
what is Gene regulation?
Gene regulation is the control of the effectiveness of any of the stages of gene expression by controlling and determining which genes are switched on and off, when, and how long for
When can gene expression be regulated?
Gene expression can be regulated at the transcription stage, at the translation stage or by the later modification of the protein that is formed.
What is a promoter gene?
A promoter gene is a gene that facilitates transcription from one or more naerby structural genes; part of an operon
What is a regulator gene?
A regulator gene is a gene that is able to produce proteins that bind to the operator gene and inhibit transcription
Why is protein shape important?
Protein molecule shape is critical for the correct functioning of the protein. A slight change in the structure can prevent the protein from functioning normally.
What are the four levels of complexity of protein structure?
- Primary structure
- Secondary structure
- Tertiary structure
- Quaternary structure
Describe the four levels of complexity of protein structure.
- Primary structure: a chain of amino acids joined by peptide bonds
- Secondary Structure: the amino acid chain forms sheets or spirals due to bonding between the different parts of the chain
- Tertiary Structure: produced by more bending and folding of the sheets and spirals
- Quanternary Structure: two or more chains are joined. In this diagram a molecule of haemoglobin is formed from four globular sub-units. Each of the sub-units also has a group containing iron
If proteins are to be used outside the cell…
they have to be packaged for secretion from the cell in which they are made
What happens at the edges of the golgi apparatus?
At the edge of the apparatus the membrane proteins pinches off to form a vesicle containing some of the modified proteins.
What is lipid/carbohydrate synthesis?
Lipid: are broken down to fatty acids and glycerol
carbohydrates: are broken down into glucose
