Cell metabolism Flashcards
Metabolism
all the chemical reactions in an organism
Catabolism
chemical reactions breaking down large molecules into smaller simpler molecules. energy is released
2 examples of catabolic reactions
respiration
digestion
Anabolism
chemical reactions building up small molecules into larger more complex ones. energy is used.
2 examples of anabolism
photosynthesis
protein synthesis
2 sources of energy
solar energy
cellular energy
An example of use of solar energy
trapped by pigments (chlorophyll) in cells and used to make chemical bonds in carbohydrates. PHOTOSYNTHESIS
Where is cellular energy found
it is held in bonds in biomolecules. when these bonds are broken down, energy is released. RESPIRATION
Transfer of energy 3 steps
solar energy
cellular energy in biomolecules
energy used to do work
What does each reaction in the body need to allow it to take place?
a different catalyst
Enzyme
biological catalyst
Substrate
the substance that an enzyme reacts with
Product
the new substance that is formed
Metabolic pathways
series of reactions linked together
Optimum temperature for enzymes in the human body
37º C
What would happen without enzymes
the rate of reactions would be too slow to sustain life
How to enzymes affect the rate of a reaction?
they lower the activation energy needed to start a chemical reaction
5 properties of enzymes
biological catalysts made of protein specific in function enzyme reactions are reversible enzyme action is affected by temperature and pH
Structure of enzymes
globular protein with a folded shape
What do some enzymes have in common
many enzymes are composed of 2 or more globular sections called domains joined together
The active site
a small part of an enzyme where the substrate attaches
Shape of active site
matches the shape of the substrate
Induced fit action
the active site changes shape as the substrate binds with it so that the enzyme fits better around the substrate
The name for the mechanism of enzyme action
the active site theory
7 steps in the active site theory
- substrate binds with active site of matching enzyme
- an enzyme-susbstrate complex is formed
- active site changes shape to fit better with substrate (induced fit)
- the substrate is changed into the product
- the product leaves the active site of the enzyme
- the enzyme returns to its original shape
- the enzyme can work again (ie. react with another substrate molecule)
can you work backward up the active site theory
yes
enzyme specificity
enzymes are specific in function. each enzyme can only act on a particular substrate.
amylase acts on
starch
pepsin acts on
protein
lipase acts on
lipids
catalase acts on
hydrogen peroxide
what causes enzyme specificity
the shape of their active site
what will affect enzyme specificity
any factor that changes the shape of the active site
when is an enzyme said to be denatured
when it undergoes an irreversible change in structure and permanent loss of function
why does an enzyme lose its function when it is denatured
the shape of the active site is altered and it can no longer fit with the substrate
2 causes of denaturation
strong heat
unsuitable pH
2 factors affecting the rate of enzyme action
Temperature
pH
optimum activity
when the rate of enzyme action is at its fastest
the 3 things you mention when they ask you to describe the graph of the rate of enzyme action
as ____ increases, the rate increases. at ____ it is at its optimum level. after that as the _____ continues to increase the rate of enzyme action decreases. after ____ it has been denatured
3 minor things that enzyme action is also affected by
enzyme concentration
substrate concentration
inhibitors
role of enzymes in metabolism
enzymes are biological catalysts that control the rate of all metabolic reactions
5 processes that enzymes are involved in
respiration photosynthesis protein synthesis DNA synthesis digestion
how to keep constant:
temperature
use water baths of the same temperature
how to keep constant:
pH
use the same pH buffer
how to keep constant:
enzyme concentration
use equal amounts of the enzyme
how to keep constant:
substrate concentration
use equal amounts of substrate
how to vary temperature
use water baths at different temperatures
how to vary pH
use different baths
experiment: enzyme
catalase (found in fresh celery or radish)
experiment: substrate
hydrogen peroxide
experiment: products
water and oxygen (O2 causes foaming)
experiment: how do you measure the amount of product produced
volume of foam produced
rate =
volume of foam produced/time
experiment: what apparatus is needed
thermometer
graduated cylinder
water bath
boiling tube
experiment: what pH buffer do you use to keep the pH constant?
pH 4 buffer
experiment: what do you add so that foam is produced?
a drop of washing up liquid
experiment: how do you add the hydrogen peroxide to the test tube
using a syringe
Which axis does temperature go on
the x axis
What axis does rate of enzyme action go on
the y axis
Experiment: how to denature the catalase
put in a boiling tube in a water bath at >60ºC
Control to the denatured experiment
unboiled catalase
Bioprocessing
the use of microorganisms or cells or enzymes to produce products
where is bioprocessing carried out
in the bioreactor (vessel/container)
4 products of bioprocessing
breads
cheeses
yogurts
wines/beers
4 more recent products of bioprocessing
antibiotics
vitamins
hormones
foodstuffs
What is used now in place of whole cells in bioprocessing
purified enzymes or immobilised enzymes
Immobilised enzymes
fixed to an inert materia eg.glass, or trapped in a gel or fixed to each other
4 advantages of immobilised enzymes
they can be reused
the product is purer
they are easily recovered at the end of the process
the enzymes are more stable and can be used for longer
3 uses of immobilised enzymes
to convert sucrose to glucose and fructose
to convert glucose to fructose for use in soft drinks (fructose is sweeter so less needed)
to produce lactose-free milk
To prepare an enzyme immobilisation and examine its application: why is yeast used
it contains the enzyme sucrase which converts sucrose to glucose and fructose
To prepare an enzyme immobilisation and examine its application: what does immobilised yeast contain
immobilised enzyme
To prepare an enzyme immobilisation and examine its application: how do you test for the presence of glucose
glucose test strips (clinistrix)
To prepare an enzyme immobilisation and examine its application: what do you mix yeast with first
mix with sodium alginate in a beaker and stir with a glass rod
To prepare an enzyme immobilisation and examine its application: what do you do with the mixture of yeast and sodium alginate
draw it up into a syringe and slowly drop droplets into a beaker with calcium chloride solution
To prepare an enzyme immobilisation and examine its application: what will form once you drop the droplets into the beaker of calcium chloride solution?
alginate beads will form
To prepare an enzyme immobilisation and examine its application: how long until the beads harden in the Calcium chloride solution
about 20 minutes
To prepare an enzyme immobilisation and examine its application: once the beads have hardened
filter the beads and wash with distilled
To prepare an enzyme immobilisation and examine its application: substrate
sucrose
To prepare an enzyme immobilisation and examine its application: enzyme
sucrase
To prepare an enzyme immobilisation and examine its application: product(s)
glucose and fructose
To prepare an enzyme immobilisation and examine its application: real experiment
beaker with sucrose and immobilised yeast beads
To prepare an enzyme immobilisation and examine its application: control experiment
beaker with sucrose and beads without yeast
To prepare an enzyme immobilisation and examine its application: what do you first do with both beakers
shake and leave for 5 minutes
To prepare an enzyme immobilisation and examine its application: very last step
test both for glucose using clinistix
