B1.2 Flashcards
what is a long molecule of dna called
chromosome
how many chromosomes are in each cell
46
what are genes
short sections of dna, codes for characteristics
what does the code each gene contains cause to be made
specific proteins, which determine the cells function
what is dna made of
small units called nucleotides, made of a sugar, a phosphate group and a base
what are the 4 bases
adenine, thymine, cytosine, guanine
what makes up a dna nucelotide
phosphate, nitrogenous base, hydrogen bonds, and common sugar(deoxyribose)
what does adenine bind with as there is no thymine in mRNA
uracil
how are proteins made
translation
what are proteins made from
amino acids; different amino acids join together to form different proteins.
what is transcription
the dna around a gene ‘unzips’. complementary bases attach to one of the dna strands. when complete, the mRNA detaches, and DNA zips back up. the mRNA then travels to ribosomes in the cytoplasm, where proteins are made.
what is translation
the mRNA attaches to a ribosome. the ribosome reads the nucleotides on the mRNA in groups of 3(codons). the ribosome continues to read the triplet code, adding more amino acids. the amino acids join together in a chain. this is a protein. each protein has a specific shape for function and many types are produced ( eg enzymes or hormones)
what are the conditions where enzymes work best called
optimum conditions
what does the rate of an enzyme- catalysed reaction depend on
temperature, pH, concentrations, conditions where the enzyme works the best are the optimum conditions.
what happens with temperature and ph when it increases ( rate of reaction)
the higher the temperature, the faster the reaction but if it gets too high, the amino acid chains in the protein start to unravel, changing the shape of the active site, causing the enzyme to denature(irreversible) and its also the same for ph
what happens with substrate concentration when it increases ( rate of reaction)
the higher the substrate concentration, the faster the rate of reaction until all the enzymes are bound to substrate molecules (reaches its maximum)
what happens with enzyme concentration when it increases (rate of reaction)
the higher the enzyme concentration, the faster the rate of reaction but if no new substrate molecules are added, the reaction will stop.
what is the definition of a biological catalyst
they speed up a reaction without being used up themselves. once a reaction is finished, they can be used to catalyse the same type of reaction again.
what are enzymes
enzymes are made of protein, and they are biological catalysts
what do enzymes do
enzymes build larger molecules from small ones, (e.g: protein synthesis) or other way round(e.g digestion)
what are enzymes made of
long chains of amino acids
how do enzymes form a specific shape
they are folded to form a specific shape where molecules or other substrates bind to the enzymes by active site.
