Btec Applied Science Unit 3

What is a hypothesis?

An Idea that you can test using practical experiments

What are the Key features of a good hypothesis?

A good Hypothesis must:
Be able to be tested scientifically
Relate one dependent variable to on independent variable

What is a Null Hypothesis?

States that there is no relationship or causality, for example, no relation between the temperature and the rate of reaction.

What does qualitative data refer to?

It refers to the appearance or value of something, such as the colour observed or whether the bubbles are produced.

What does Quantitative data refer to?

It refers to numerical measurements made, such as the volumes and times measured.

What is SOP?

The Standard Operating Procedure. This is an established procedure or method used to carry out a routine activity. It ensures consistent results every time.

What are some examples of SOPs?

Titration, Handling of chemicals, disposal of waste, qualitative analytical tests, preparing solutions

What are risk assessments?

It identifies hazards, evaluates the risks associated with those hazards and it determines ways to eliminate or control those risks.

What is a Hazard?

When the equipment or substance can cause harm, for example a hot plate or hydrochloric acid

What is a risk?

The harm that the hazard could cause and the chances of it happening, for example the risk of using a hot plate is getting burnt.

What is the independent variable?

The variables you change during an investigation.

What is the Dependent variable?

The variables you are investigating and measure during an investigation.

What is the control variable?

The variables you keep constant during an investigation.

What should a method be?

A step-by-step set of instructions, Be logically ordered, allows you to take sensible measurements, and allows you to test your hypothesis.

When planning your method what do you need to make sure?

That it will procedure a range of results, reliable results, precise results, and accurate results.

What are some types of data?

The data can be continuous such as the age of plant ir number of plants. Some data can be a mixture of numbers and names such as the number of different types of plants found in a garden.

What data is normally displayed on a bar chart?

Continuous data. You need to make sure its a smooth curve of best fit, and that the curve goes through or near most of the points.

What are bar charts used for?

They are used for discrete data but can be used to compare different sets of data.

What is the Pattern on the graph?

The shape of the graph. It is the line that goes up as time goes by but eventually levels off

What is the trend on a graph?

The relationship between factors on the graph or in the table. The full trend is that the volume increases as the time increases but then levels off after a certain amount of time.

What is the sample size?

The number of people sampled in the investigation. To be confident in your conclusions you need a large sample size to give strong evidence.

What is Primary data?

This is the data that you have gathered for yourself through the experiments or investigations .

What is secondary data?

The data that you get in books, scientific papers or the internet. You should compare your primary and secondary data to draw a conclusion

How do you know if the data is anomalous?

It doesn't fit into the pattern of the other results. It does not lie close to the line of best fit.

What can cause the anomalous data?

Not following the method correctly. inaccurate measuring/recording and impurities.

What is systemic error?

The error that is built into the method or equipment which you are using. This can be corrected by calibrating the balance. These errors are quantitative.

What is the random error?

These are due to not following the method correctly and can be minimized by repeating results and taking averages.

What can misreading the observations cause

They can cause qualitative errors.

What is the accuracy?

How close is the data to the true value? Errors due to the equipment could make the results less.

What is the reliability?

How trustworthy the data is. It is usually ensured by repeating the readings to identify any anomalous results.

What is precision?

How close the repeat readings are to each other. It can be improved by using measuring equipment that measure to more decimal places.

What is an enzyme?

A protein molecule that acts as a catalyst in a biochemical reaction.

What are proteins made up of?

amino acids

What four chemical groups are attached to the central (alpha) carbon?

A hydrogen atom. A amino acid. A carboxyl group. A variable R group (side chain).

How many different R groups are there?

There are 20 different R groups which means there are 20 different amino acids.

What are amino acids linked together by?

Peptide Bonds.

What does a condensation reaction occur between?

Two amino acids.

What is produced in a condensation reaction?

Water.

What is a dipeptide formed by?

Two amino acids linked by a peptide bond.

What do three amino acids form?

A tripeptide

What do many amino acids join to form?

A polypeptide

What is a polypeptide with more than 50 amino acids called?

A protein.

What is an active site?

The part of an enzyme where the biochemical reaction takes place.

What is a secondary structure?

Where a polypeptide chains form orderly shapes.

What are secondary structures held in shape by?

Hydrogen bonds between the -NH of one of the peptide link and the -C=O of another amino acid

What is tertiary structure?

a three dimensional shape of a secondary structure

What does the tertiary structure give?

It gives the enzyme the shape of its active site.

What are the most common shapes of secondary structures?

Coiled α-helix and folded β-pleated sheet

What does the active site consist of?

A small number of amino acids which form a specific shape because of the proteins secondary and tertiary structure.

When an enzyme catalyzes a reaction where does it take place?

It takes places on the active site of an enzyme.

What do enzymes work specifically to?

catalyse one type of biochemical reaction.

In a biochemical reaction what are substrates converted to?

They are converted into products.

What does the substrate bind to?

The active site. Only specific substrates will bind to a particular enzymes site.

What shape does the substrate have?

They have a complementary shape to the shape of the active site on the enzyme.

What happens after the reaction?

The product is released and the active site is available to catalyse further reactions.

The active site is a specific shape that only the substrate will fit, What happens to the active site is the temperature goes too high?

The temperature is too high, the hydrogen bond will break. This means the enzyme changes its shape so the active site loses its shape. The enzyme is denatured and co no longer act as a catalyst.

What is a catalyst?

It is a substance that speeds up a reaction. It can take part in the reaction but is left unchanged at the end of the reaction.

What catalysts are enzymes?

They are biological catalysts.

What is the collision theory?

For a reaction to occur, the particles must collide and the particles must have enough energy to react.

What dos the energy of the collision depend on?

It depends on the speed of the particle and the angle they collide.

What is the activation energy?

The minimum energy needed for particles to react.

Why does the enzyme lowers the activation energy needed?

The more particles have the required energy to react. There are more successful collisions. And there is a faster reaction.

What is the catalytic activity?

The increase in the rate of a reaction caused by the inclusion of an enzyme.

What is the substrate?

The molecule that is affected by the activation of the enzyme.

What is the active site?

The area of an enzyme where a substrate binds.

What does denatured mean?

When the tertiary structure of the enzyme is changed.

How can enzyme reactions be measured?

They can be measured by measuring a decrease in the substance. By measuring the increase in the product, this makes is easier because you know the starting measurement for the product will be 0.

Why must the initial rate of reaction be recorded?

It needs to be measured because the rate will decrease as the substrate is used up and its concentration decreases.

What does the enzyme need, in order to work effectively?

Specific conditions.

What happens if the specific conditions are not present?

The enzyme-catalysed reaction may slow down or might not work at all

What is the optimum temperature?

Each enzyme has a optimum temperature at which it works fastest.

What happens as the temperature increases to the optimum temperature?

The reaction rate also increases.

What happens below the optimum temperature?

There is less energy which means there is fewer collisions and therefore a slower reaction.

What happens above the optimum temperature?

The hydrogen bonds in the enzyme breaks and the enzyme and active site loses its shape and therefore there is no catalysis

What do enzymes have?

An optimum pH

What does pH affect on the active site?

The charge. If the pH changes then the charges on the active site changes ad the substrate may no longer be able to bind to it

What can the concentration of the enzyme and substrate affect?

The rate of reaction.

What happens if the concentration of the substrate is too high?

There will be no more active sites for them to bind to. Increasing the concentration of the substrate will no longer affect the rate of reaction

What happens if the concentration of the enzyme is too high?

There are too many free available active sites compared to the substrate molecules, the rate of reaction no longer increases.

What is diffusion?

Diffusion is the movement of substances from a region of high to low concentration.

What can diffusion occur across?

It can occur across a membrane. As long as the molecules are small enough to pass through the membrane then diffusion will occur

What factors affect the rate of diffusion?

Size- The larger molecules move more slowly then smaller ones, so the rate of diffusion decreases.
Temperature- A higher temperature increases the energy molecules have and so they move faster, increasing the rate of diffusion.
Distance through a substance- The greater the distance that the molecules must travel through a substance, the slower the rate of diffusion.
Surface area- As surface area increases, the area of which molecules cans spread is increased and so he rate of diffusion increases.
Shape of the surface of which the molecule is diffusing- the shape of the surface of which the molecule is diffusing can affect the rate of diffusion.

What does the kinetic theory explain?

It explains the properties of different states of matter. It also explains diffusion

What is the arrangement of particles in a solid?

They are close together in a regular pattern.

What is the arrangement of particles in a liquid?

They are close together in a random pattern.

What is the arrangement of particles in a gas?

They are far apart and in a random pattern.

What are the properties of solids?

They are in a fixed shape and they cannot flow. They cant be compressed or squashed.

What are the properties of liquids?

They take shape of a container, they flow and move randomly. They cannot be compressed or squashed.

What are the properties of gases?

They completely fill container and they can flow and move randomly. They can be compressed or squased.

Where can diffusion happen within?

A mixture of liquids, a mixture of gases, and a mixture of liquids and gases.

How do humans improve the growth of crops?

They correct soil pH, optimum watering. Correct nutrients present

How can humans have a negative effect on plant growth?

Trampling. Picking wildflowers. Removing hedges/tress.

How can humans have an effect of the distribution of plants?

Sowing crops means field with only one type of plant. Trampling can cause unusual or more widespread distribution patterns due to seeds being carried on the bottom of shoes.

What pH doe plants grow best at

Between 4.5 and 7.5

What does acidic soil mean?

It can mean that there is a deficiency in necessary minerals, such as iron and manganese.

Why is Soil Aeration necessary?

It is necessary to allow sufficient oxygen to get to the plant and for carbon dioxide to be removed.

What forms when there is little aeration?

Toxins form such as hydrogen sulfide gas.

Why is temperature important in plants?

Most plants have a optimum temperature they will grow at. The temperature is important for seed germination, seeds need the soil to be within a specific temperature range in order for them to germinate.

What three things are important for plant growth?

Light, water and minerals.

Why do plants need light?

They need light for photosynthesis. Plants in high light intensity are more likely to grow better than those in shade. Plants that are used to low light intensity may get scorched in the sun.