Stage 2 Biology

Question	Answer
What is semi-conservative replication? Why is it given this name?	semi conservative replication is the type of replication that occurs to DNA. It is given this name as one old strand and one new strand is used.
What do bases have to do with DNA? What pairs with what?	Bases make up the code for the DNA strand. A&T G&C
The backbone of the DNA is made up of what?	Deoxyribose sugar
What are the three elements that make up a nucleotide?	1 sugar 1 phosphate 1 base
Repeating units of starch, glycogen and cellulose make what?	A polysaccharide
Animals store glycogen where? Plants store what for use in aerobic respiration?	In the liver and the muscles. Starch.
Chitin is found in the what of what animal?	Exoskeleton of insects
Why is lipids important? What are included as lipids?	For energy and structural purposes. Phospolipid, fats, waxes, oils and steroids.
Why are phospolipids important?	Phospolipids are important as they are critical in the structure of the cell membrane. They for the phospolipid bi-layer.
Oils are found mainly in plants in what form?	seeds.
mRNA stands for what? mRNA is involved with what? Thymine is replaced with what on this strand?	messenger RNA. Protein synthesis. Thymine is replaced with uracil.
tRNA stands for what? What role does it play?	Transfer RNA. The function of the tRNA is to place amino acids on the mRNA strand to make a polypeptide chain.
Proteins are made up from how many amino acids? How many polypeptide chains make a protein?	20. 1 or more.
Discuss what occurs during transcription.	In transcription, a mRNA molecule is synthesised from a gene on a DNA. RNA polymerase enzymes separate the two strands of DNA and the mRNA molecules move in to copy the base sequence of one side of the DNA. It copies it in a complimentary manner. Once the section has been copied the mRNA moved into the cytoplasm and the DNA re-joins.
What occurs in translation?	In the translation stage a polypeptide chain is made using the codon sequence from the mRNA. tRNA molecules are required to carry free amino acids in the cytoplasm. The tRNA receives signals from ribosomes that read the codes. The ribosomes also help to synthesis the polypeptide chain as amino acids are added. Translation can occur in three stages: 1. Initiation, start codon is recognised by ribosomes. 2. Chain elongation, binding of amino acids from the codons. 3. Termination, stop codon is reached, poly peptide is complete & protein is ready for use.
What is a primary structure?	is a unique sequence of amino acids.
the coiling or folding of a protein that contributed to the shape of it is known as the..?	secondary structure
what a protein becomes 3D and gives rise to its functionality it is known as the what structure?	Tertiary.
Proteins that have two or more polypeptide chains are known as what?	Quaternary structure
Some proteins act as receptor proteins for molecules. Describe their shape.	Their shape varies but is specific to the particular messenger than would attach to it. E.g. a particular hormone.
Define enzyme.	An enzyme is a biological catalyst. The 3D shape determines its function. Enzymes have an induced fit. Enzymes are not changed during the reaction.
What is the difference between a competitive and non-competative inhibitor and what is their role?	Competitive competes for the active site and blocks the substrate from binding. Non-competitive binds elsewhere and changes the shape of the active site. Both stop products from being produced.

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	Created by islamapleson almost 10 years ago