MCQ 1_5B Enzymes Conditions – National 5 Unit 1 Homework

1.	One of the properties of enzymes in the initiation of chemical reactions is that an enzyme
	A.	does not alter the energy input required
	B.	raises the energy input required
	C.	lowers the energy input required
	D.	raises then lowers the energy input


2.	Which term refers to the process by which complex molecules are formed from simple molecules?
	A.	Digestion
	B.	Synthesis
	C.	Degradation
	D.	Respiration


3.	The substrate for phosphorylase is
	A.	glucose
	B.	glucose-1-phosphate
	C.	phosphate
	D.	starch


4.	Some synthesis reactions build storage molecules. Such molecules will be
	A.	used to build the body of the organism
	B.	used immediately for energy
	C.	broken down again when they are needed
	D.	kept until it is convenient to remove them from the organism


5.	Some synthesis reactions build structural molecules. Such molecules will be
	A.	used to build the body of the organism
	B.	used immediately for energy
	C.	broken down again when they are needed
	D.	kept until it is convenient to remove them from the organism


6.	As the temperature is raised from 10°C to 60°C the activity of an enzyme
	A.	increases then decreases
	B.	increases
	C.	decreases
	D.	decreases then increases


7.	For an enzyme, the optimum temperature is
	A.	the hottest temperature at which it can work
	B.	the temperature at which it works fastest
	C.	the coldest temperature at which it can work
	D.	any temperature at which it can work


8.	What is the optimum temperature for human enzymes?
	A.	25°C
	B.	37°C
	C.	40°C
	D.	60°C


9.	What happens when an enzyme is heated strongly?
	A.	it changes colour
	B.	it acts faster
	C.	it is neutralised
	D.	its structure changes


10.	When an enzyme is heated to 60°C it is denatured. This means that it will
	A.	never work again
	B.	only work when cooled to 37°C
	C.	permanently work faster
	D.	now be at its optimum temperature


11.	If an enzyme is denatured it means that
	A.	it acts faster on substrates
	B.	its active site is altered in shape
	C.	the substrate fits the active site better
	D.	it continues working


12.	The pH scale measures
	A.	enzyme activity
	B.	glucose production
	C.	digestive system temperature
	D.	acidity or alkalinity


13.	In an experiment it was found that an enzyme worked well at pH 4, but not at pH 7 or pH 11 Which of the following is a valid conclusion?
	A.	pH 7 is the optimum for this enzyme
	B.	the enzyme works best in acidic conditions
	C.	the enzyme works best in alkaline conitions
	D.	the enzyme works best in neutral conditions


14.	What is the optimum pH for pepsin?
	A.	around pH 2
	B.	around pH 4
	C.	around pH 7
	D.	around pH 9


15.	Most cellular activities are processes regulated by the action of —
	A.	DNA
	B.	enzymes
	C.	phospholipids
	D.	proteins
	E.	mRNA

16.

This graph shows that —

more enzymes are present at a higher pH

pepsin is less sensitive to pH than trypsin

pepsin is less effective at low pH than trypsin

pH affects the activity rate of enzymes


17.	This graph shows that —
	A.	more enzymes are present at a higher pH
	B.	pepsin is less sensitive to pH than trypsin
	C.	pepsin is less effective at low pH than trypsin
	D.	pH affects the activity rate of enzymes

18.

The molecule represented below is found in living things. Which statement describes one characteristic of this molecule?

It is the template for the replication of genetic information

Enzymes are made up of these molecules

It is different in each cell of an organism

Cell membranes contain many of these molecules

19.

Which model best represents the relationship between a cell, a nucleus, a gene, and a chromosome?

20.

The diagram below represents a chemical reaction that occurs in the human body. Which statement describes a characteristic of molecule Z?

Molecule Z will function at any temperature above 20°C.

Molecule Z is composed of a string of molecular bases represented by A, T, G, and C.

Molecule Z will function best at a specific pH.

fertilize the eggs in sea water that does not contain radioactive thymine

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