b1.2-What Happens in Cells? Flashcards
b1.2.1-What does DNA look like?
There is DNA in the nucleus of each cell. Each long molecule of DNA is a chromosome and people have 46 chromosomes in each of your cells. Short sections of DNA that code for characteristics are genes.
b1.2.1-What is the structure of DNA?
DNA is made up of two strands joined together by bases. The strands are twisted together to form a double helix. DNA is a polymer and made of small units called nucleotides. Each nucleotide is made up of a sugar, phosphate group and base.
b1.2.1-How do bases in DNA bond?
To hold strands of DNA together, a base from one strand bonds with a base on the other strand. This forms a base pair which is a complementary base pairing.
Adenine-Thymine(A-T), Cytosine-Guanine(C-G)
b1.2.2-How is mRNA produced?
A copy of DNA is mRNA which is a single copy of DNA. It’s produced in transcription which is when the DNA around a gene unzips so both strands are separated. The complementary base pairings match up and the DNA zips up.
b1.2.2-How are proteins made?
Different amino acids produce different proteins and they’re produced by translation. The mRNA attaches to a ribosome which read the nucleotides in groups of three(base triplets). Each triplet codes for a specific amino acid until the amino acids join together in a chain.
b1.2.3-What are enzymes?
Enzymes are made of protein. They are biological catalysts meaning they speed up reactions without being used up themselves. They build larger molecules from smaller ones and break down larger molecules into smaller ones.
b1.2.3-What do enzymes look like?
Enzymes are made up of long chains of amino acids and folded together to make a specific shape. The active site is where molecules of other substances bind to the enzyme. The molecule that binds is the substrate.
b1.2.3-Do enzymes bind to all molecules?
Enzymes are highly specific meaning they can only bind to one type of substrate molecule. The substrate must fit exactly into the active site to bind. They work like a lock and key which is the lock and key hypothesis.
b1.2.4-How does temperature affect enzyme controlled reactions?
Higher temperature means faster reaction. If it becomes too high, amino acids start to unravel changing the shape of the active site. The enzyme is now denatured meaning the substrate can’t bind and rate of reaction decreases. The change is irreversible and the reaction stops.
b1.2.4-How does pH affect enzyme-controlled reactions?
Each enzyme has an optimum pH and a change in pH affects amino acid interactions in a chain. This may make enzyme unfold changing the shape of the active site and leaving the enzyme denatured.
b1.2.4-What other factors affect enzyme-controlled reactions?
The higher the substrate concentration, the faster the rate of reaction. A certain substrate concentration means enzyme molecules bound to substrate molecules. Any further increase in substrate concentration won’t increase rate of reaction as there are no enzymes to bind to.
