Active Transport AND enzymes Flashcards
What is active transport
- Active transport is the movement of a substance from an area of low
concentration to an area of high concentration up/against a concentration
gradient. It is an active process, so it requires energy/ATP, and this
process involves ion pumps/protein channels. Carrier proteins are needed
What is a carrier protein
- Carrier proteins change their shape to carry the substance across the
cell membrane - Energy is required to change the shape of carrier protein
Compare passive transport vs active transport
- Facilitated diffusion requires
channel proteins, however, these
proteins don’t change shape and
are always open, so no
energy/ATP is required - Active transport requires carrier
proteins which change shape
(open and close), so energy/ATP is
required
What is cytosis
It is a form of active transport. Bulk movement of materials
into/out of the cell by
manipulating the cell
membrane. There are two types: Endocytosis and Exocytosis
What is endocytosis
Bulk movement of a substance
INTO the cell by manipulating the
cell membrane via the assistance of
a vesicle. It occurs from an area of
low concentration to an area of high
concentration up/against a
concentration gradient. It is an
active process, so requires energy
What is exocytosis
Bulk movement of a substance OUT of
the cell by manipulating the cell
membrane via the assistance of a vesicle.
It occurs from an area of low
concentration to an area of high
concentration up/against a concentration
gradient. It is an active process, so
requires energy
What are enzymes
Enzymes are biological catalysts and proteins
- Enzymes are catalysts because they speed up the rate of chemical
reactions while remaining unused - Enzymes typically end in ‘-ase’ (ex. lipase)
What are some examples of enzymes
Examples of enzymes in our everyday life:
- Lipase: breaks down lipids/fats
- Protease: breaks down proteins
- Amylase: breaks down starch
- Lactase: breaks down lactose
What is activation energy
Activation energy is what is needed to get the particles to collide at the
right speed and in the right orientation for the reaction to proceed
What are catalysts
Catalysts lower the activation energy of a biochemical
reaction, which in turn, increases the rate of a reaction
- The higher the activation energy, the slower the
chemical reaction will be. This is because molecules can
only complete the reaction once they have reached the
top of the activation energy barrier - A lower energy requirement means the reactant
molecules can reach their transition state (products)
more quickly and the overall reaction can happen faster - Catalysts don’t get used up because they aren’t
consumed in the reaction
What is the active site of enzymes
The enzyme’s active site causes the enzyme to
be specific to certain chemical reactions.
Different reactions will have different enzymes
that catalyse them
What is the role of catabolic enzymes
- Breaks down substrate into
multiple products - Ex. Lactase (enzyme) breaks
down lactose (substrate) into
glucose and galactose
(products)
What is the role of anabolic enzymes
- To combine multiple substrates
into one product - Ex. DNA polymerase
combines nucleotides
together into a long strand
What is the enzyme cycle
- The enzyme has an active site that is
specific to a substrate - The substrate attaches to the active site
to form the enzyme-substrate complex - The enzyme catalyses the reaction,
forming the enzyme-product complex - The enzyme releases the product(s), and
the active site is emptied to be reused again
What is the lock and key model
The substrate fits exactly into the enzymes active site like a key
(substrate) fits into its lock (enzyme)
