b1.2 what happens in a cell Flashcards
structure of DNA
what is the body made up of ?
organs
what are organs made up of ?
cells
what does each cell contain ?
nucleus
what does the nucleus contain ?
chromosomes
what are chromosomes made up of ?
molecules called DNA
what does DNA stand for ?
deoxyribonucleic acid
what do the DNA molecules look like ?
twisted ladder consisting of two strands
what is the spiral shapes called ?
double helix
what are the four bases ?
adenine(A)
thymine(T)
cytosine(C)
guanine(G)
what can A pair with ?
T
what can T pair with ?
A
what can C pair with ?
G
what can G pair with ?
c
what are the sides of the DNA molecules made up of ?
a phosphate-sugar backbone
what is the centre of a DNA made up of ?
the 4 bases
what is a gene ?
the length of DNA that gives the instructions for the making of a certain protein
what is an enzyme?
a protein that acts as biological catalyst
what is a catalyst?
substances that speed up a chemical reaction without being used up in the reaction
what is an active site?
the part of the enzyme that the substrate fits into
what is protein?
molecules made up of long chains of amino acids joined by peptide links
what happens first to the substrate?
it binds to the active site on the enzyme
what happens when the substrate binds to the active site on the enzyme?
an enzyme-substrate complex is formed
what happens when an enzyme-substrate complex is formed?
a chemical reaction takes place which makes products
what happens after a chemical reaction takes place?
the products are release from the active site
can the enzymes be used again?
yes
what are enzymes effected by?
temperature and PH
what happens if the temperature in an enzyme becomes too high?
the active site starts to change shape
EXAM QUESTION-
describe the shape of the graph( 3 marks)
IN BOOK YR9
-between 0-40 degrees an increase in temperature increases enzyme activity
-at 40 degrees optimum rate of activity increases
-after 40 degrees enzyme activity decreases
EXAM QUESTION-
explain the shape of the graph(3 marks)
IN BOOK YR9
-more kinetic energy—> more enzyme substrate complexes formed—> faster rate of reaction
-as enzymes denature active site no longer fits substrate
PAST EXAM QUESTION-
describe the shape of the graph(2 marks)
IN BOOK YR9
-at a Ph of 3 for pepsin the rate of activity increases
-after a PH of 8 for trypsin thee enzyme activity decreases
PAST EXAM QUESTION-
explain the shape of the graph(3 marks)
IN BOOK YR9
- the shape of the graph for trypsin is like that after a PH of 8 because the substrate can no longer fits the active site
-outside the optimum PH the enzyme denatures
