Beginnings and Endings Answers

Beginnings Endings

Cell division is essential (needed) for

growth and repair

During cell division the parent cell divides to form

two identical daughter cells

The daughter cells always have the same

number of chromosomes

Uncontrolled cell division can

lead to cancer

Cell Division

DNA, Genes & Chromosomes

Beginnings Endings

The chromosomes are found in

the nucleus of a cell

Genes are found on

chromosomes

Lots of genes make up

strands of DNA

DNA is like a code for

making protein

Genes are passed on from parents to

offspring

DNA can be used to help solve crime because each person’s DNA

is different to everyone else

Therapeutic Uses of Cells

Beginnings Endings

Genetic Engineering can be used to make

insulin

Genetic Engineering involves the transfer of a gene from one organism

to a different organism

Stem cells are

unspecialised cells

An example of an organism that is often used in Genetic Engineering is

bacteria

Stem cell technology uses stem cells to grow

new organs for transplant

Enzymes

Beginnings Endings

Enzymes are found

in all living cells

Enzymes are used by cells to

speed up chemical reactions

Each enzyme is specific which means it will only

act on one type of substance

Enzymes are unchanged during chemical reactions

so they can be used again

Washing powders that contain enzymes are called

biological detergents

Each enzyme works best in certain conditions of temperature and pH called the

optimum

Microorganisms in Industry

Beginnings Endings

Microorganisms can be useful in industry because

They multiply very quickly

Examples of useful microorganisms include

yeast and bacteria

Yeast is used in industry to make

Bread and beer

Bacteria are used in industry to make

Cheese and yoghurt and to break down sewage

Bacteria and yeast can be grown in large containers called

fermenters

Photosynthesis

Beginning Ending

Photosynthesis is a chemical reactions that happens when plants use light energy

to make food

For photosynthesis to happen plants need

light, water, carbon dioxide, chlorophyll and a suitable temperature

Chlorophyll is a green chemical found in leaves

that can trap energy from light

Plants make sugars called glucose that are

stored as starch or used for growth

The waste product of photosynthesis is

oxygen

If light or carbon dioxide are in short supply or if it too cold then

the rate of photosynthesis will be limited or slower than normal

Factors affecting Respiration

Beginning EndingsRespiration is a process cells use to

Release energy from food

There are two kinds of respiration:

Aerobic and anaerobic

Aerobic respiration means

With oxygen

Anaerobic respiration means

Without oxygen

Aerobic respiration produces carbon dioxide and water

As waste products

Anaerobic respiration in animals produces

Lactic acid

Anaerobic Respiration in plants and yeast produces

Alcohol and carbon dioxide

Respiration needs enzymes to happen so the speed it happens is affected by

Temperature

Revision Cloze Passage AnswersKey Area 1. Cell Division and its role in growth and repair.

1. Genes are located on chromosomes in the nucleus.

2. Genes are made of DNA which carries the instructions to make proteins.

3. Each individuals DNA is unique.

4. Genes are passed from parents to offspring.

Word Bank

nucleus DNA protein parents

offspring genes unique

Key Area 2. DNA, genes and chromosomes.

Key Area 3. Therapeutic use of cells.

1. Genetic engineering can be used to produce bacteria that can produce human insulin.

This can be used to treat people who are diabetic.

2. Genetic engineering can be used to produce human growth hormone. This can be

used to treat dwarfism.

3. Stem cells exist that can be used to grow artificial tissue or organs.

Wordbank

diabetic tissue dwarfism insulin

genetic growth hormone engineering stem

bacteria

Key Area 4. Properties of enzymes and use in industries.

1. Enzymes are found in all living cells.

2. Enzymes are specific - they only act on one substrate. For example, amylase only acts

on starch and catalase acts only on hydrogen peroxide.

3. Enzymes speed up reactions and remain unchanged by the reaction.

4. Enzymes can build up and break down molecules.

5. Enzymes can be used in a range of industries. For example, rennet is used to make

cheese.

Wordbank

specific catalase speed up unchanged

starch Enzymes build up rennet

break down living cheese

Key Area 5. Properties of microorganisms and use in industries.

Microorganisms grow rapidly and can be used as a source of foods like Quorn and

Marmite.

Microorganisms include bacteria and fungi and are to make a wide range of useful

products.

Yeast is a fungus and is used in the baking and brewing industry. Yeast is also used to

make the fuel Gasohol.

Bacteria are used to produce yoghurt, cheese and biofuels.

The fungus Penicillium is used to make the antibiotic penicillin.

Wordbankmicroorganisms yeast Quorn penicillin

useful rapidly Gasohol Marmitecheese baking

Key Area 6. Photosynthesis- Limiting factors.

1. Plants use the process photosynthesis to convert light into food.

2. The rate of photosynthesis can be controlled by three factors. Carbon dioxide concentration, light

intensity and temperature. They are described as limiting factors

3. If any of the limiting factors are in short supply, photosynthetic rate will be slow.

4. If limiting factors are present at optimum levels, increased photosynthesis will lead to faster plant

growth.

Wordbank

factors limiting intensity three

plants photosynthesis slow growth

short concentration sunlight

Key Area 7. Factors affecting respiration

1. Respiration is the process that releases energy in cells. There are two types of respiration.

2. When oxygen is present, all cells carry out aerobic respiration and convert glucose into

water and carbon dioxide. A large amount of energy is released.

3. When oxygen is absent, cells carry our anaerobic respiration. A small amount of energy is

realised. In plant and yeast cells, glucose is converted into alcohol and carbon dioxide. In

animal cells, glucose is converted into lactic acid.

4. Respiration is controlled by enzymes and is affected by temperature.

Wordbank

enzymes large alcohol temperature

aerobic small present glucose

oxygen energy Respiration (x2) two

Key Area 8. Controversial biological procedures.

1. Immunisation. Humans can use immunisation to protect people from common diseases such as small pox, measles and

mumps. Some people believe that immunisations are unsafe and can lead to other problems such as autism in children.

2. Natural selection. The theory of natural selection explains how all organisms evolved on Earth. It does not use religion to

describe how this happened. Some religious people believe that life was created by God. Some people believe the Book of

Genesis in the bible describes how all plant and animals was created.

3. Stem cell technology. Human embryos can be manipulated to become stem cells. Stem cells can be used to grow replacement

skin and heart tissue. This is controversial as a human embryo cell has to be destroyed to carry out this procedure.

4. Mammalian cloning. A clone is an identical copy of a single organism. Scientists have been able to produce clones of many

mammalian species. These clones can be used to improve yield in agriculture. For example, a pig that produces a large litter of

piglets could be cloned and the number of piglets produced by farmers would increase greatly. Some people feel that this

technology could be used to clone humans and is cruel to animals.

WordbankEarth autism God religion

small pox Bible natural selection humans

piglets increase humans animals

stem embryos heart mammalian

mumps clone yield