Unit 3 Applied Science

What are proteins made up of?

Amino acid residues joined together by peptide links.

What are peptide links?

A group of covalent chemical bonds formed by 2 amino acid molecules.

How is a polypeptide formed?

When more than two amino acids join together.

What is a protein?

When a polypeptide contains 50 or more amino acid residues.

What happens when the active site is altered?

It will not bind with the substrate, meaning the enzyme is denatured.

What does "biological catalyst" mean?

It speeds up reactions in the body.

What is "Collision Theory"?

Particles must collide with enough energy for a reaction to occur.

4 ways to increase the rate of reaction?

Increase temperature, increase concentration of a reactant, increase surface area, adding a catalyst.

What does a catalyst do?

It lowers the activation energy of the reaction.

What does "Lock and Key" mean?

The substrate has one specific shape which fits exactly into the enzyme's active site.

What is the "Enzyme-substrate complex"?

Binding of the enzyme and the substrate, which then speeds up the chemical reaction by lowering the activation energy.

How does substrate concentration affect enzyme activity?

Increasing the concentration also increases the rate of reaction. This is because there is more particles in a given volume, which means more frequent collisions and more substrate molecules bind with enzyme molecules.

How does temperature affect enzyme activity?

Increasing the temperature also increases the rate of reaction until the temperature goes above the optimum, above that enzymes begin to denature.

How does pH affect enzyme activity?

Each enzyme has an optimal pH at which it can perform at its maximum rate. Too high or too low of a pH deviates the enzyme from its maximum rate.

What is the optimum temperature of an enzyme?

37 degrees Celsius.

What is "Kinetic Theory"?

All matter consists of tiny particles that are in constant motion.

How does the concentration gradient affect the rate of diffusion?

Increasing concentration gradient increases the rate of diffusion.

How does shape/size of molecules affect the rate of diffusion?

Smaller molecules diffuse quicker over larger molecules, long thin molecules diffuse quicker than short fat molecules.

How does temperature affect the rate of diffusion?

The higher the temperature, the faster the rate of diffusion. This is because the particles have more energy so they move around faster

How does distance affect the rate of diffusion?

The shorter the distance the faster the rate of diffusion.

This is because particles need to move a shorter distance to reach an equilibrium.

How does surface area affect the rate of diffusion?

Diffusion takes place through a semi-permeable membrane. The greater the SA of the membrane, the faster the rate of diffusion of molecules through the membrane.

What is dynamic equilibrium?

When two processes take place at the same rate so there is no further change in concentration of the substances involved.

What biotic factors affect plant growth and distribution?

Trampling, habitat destruction, pollution, use of chemicals (likely to reduce biodiversity), monocultures (only growing one type of plant in a field).

What is aeration?

Introducing air to soil.

What abiotic factors affect plant growth and distribution?

Soil pH and aeration, light intensity, temperature, mineral ions

What is one way to use random sampling in a habitat?

Take samples at random distances across the habitat.

What is a second way to use random sampling in a habitat?

Use a computer to generate random co-ordinates and plot in a habitat.

What is a third way to use random sampling in a habitat?

Select co-ordinates on a map and use a GPS to find the exact position in the habitat.

What sampling techniques are there?

Random, systematic, stratified, opportunistic, line transects, belt transects, quadrats, point frames.

What is random sampling?

Sampling locations are chosen at random.

What is systematic sampling?

Samples are taken at regular intervals.

What is opportunistic sampling?

Weakest form of sampling. Measures the organisms conveniently available.

What are line transects?

A tape is stretched across an area, organisms touching the tape are recorded.

What are belt transects?

A series of quadrats placed along a line at regular intervals.

What are quadrats?

Square frames that can be used to estimate population sizes.

What are point frames?

Frames with long needles, organisms touching the needles are recorded.