AQA GCSE Additional Science

Unit 1: Biology 2

2.1 Cells and simple cell transport 2.2 Tissues, organs and organ systems

Steve Bishop November 2013

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Table of Contents

B2.1 Cells and simple cell transport ...................................................................................... 3

B2.1.1 Cells and cell structure ........................................................................................... 4

B2.1.2 Dissolved substances ............................................................................................. 7

B2.2 Tissues, organs and organ systems............................................................................ 11

B2.2.1 Animal organs ...................................................................................................... 11

B2.2.2 Plant organs ......................................................................................................... 14

GCSE-Style questions: cells, tissues & organs ................................................................... 16

GCSE-style questions: Digestion ........................................................................................ 25

Find the odd one out ........................................................................................................ 27

Blockbusters .................................................................................................................... 29

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B2.1 Cells and simple cell transport All living things are made up of cells. The structures of different types of cells are related to their functions. To get into or out of cells, dissolved substances have to cross the cell membranes. Can you: ■ relate the structure of different types of cells to their function? Key words

Cell

Nucleus

Cytoplasm

Cell membrane

Mitochondria

Ribosomes

Cellulose

Chloroplasts

Vacuole

Sap

Genes

Yeast

Organism

Diffusion

Concentration

Respiration

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B2.1.1 Cells and cell structure

a) Most human and animal cells have the following parts:

■ a nucleus, which controls the activities of the cell ■ cytoplasm, in which most of the chemical reactions take place ■ a cell membrane, which controls the passage of substances into and out of the cell ■ mitochondria, which are where most energy is released in respiration ■ ribosomes, which are where protein synthesis occurs.

b) Plant and algal cells also have a cell wall made of cellulose, which strengthens the cell. Plant cells often have:

■ chloroplasts, which absorb light energy to make food ■ a permanent vacuole filled with cell sap.

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c) A bacterial cell consists of cytoplasm and a membrane surrounded by a cell wall; the genes are not in a distinct nucleus.

Nucleus – controls the activities of the cell.

Cytoplasm – where most of the chemical reactions take place.

Cell membrane - controls the passage of substances in and out of the cell.

Mitochondria - where most energy is released in respiration.

Ribosomes - where protein synthesis occurs.

Cell wall – made of cellulose and strengthens plant cells.

Chloroplasts - absorb light energy to make food in plant cells.

Permanent vacuole - filled with cell sap in plant cells.

Comparison of a plant and animal cell

Both have

Plant has that animal cell doesn’t

Animal cell has that plant doesn’t

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d) Yeast is a single-celled organism. Yeast cells have a nucleus, cytoplasm and a membrane surrounded by a cell wall.

Bacteria

Bacterium is a single-celled organism.

A bacterial cell consists of cytoplasm and a membrane surrounded by a cell wall.

The genes are not in a distinct nucleus.

e) Cells may be specialised to carry out a particular function.

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Cells, Tissues and Organs PowerPoint Notes

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B2.1.2 Dissolved substances

Movement into and out of cells

To get into or out of cells, dissolved substances have to cross the cell membranes.

Solutes = particles in solution eg glucose, sodium ions, chloride ions.

Solvent = liquid in which the particles are dissolved eg water.

Solute and solvent molecules move around randomly.

Solutes can move into and out of cells by diffusion. a) Dissolved substances can move into and out of cells by diffusion. b) Diffusion is the spreading of the particles of a gas, or of any substance in solution, resulting in a net movement from a region where they are of a higher concentration to a region with a lower concentration. The greater the difference in concentration, the faster the rate of diffusion.

c) Oxygen required for respiration passes through cell membranes by diffusion.

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B2.2 Tissues, organs and organ systems

The cells of multicellular organisms may differentiate and become adapted for specific functions. Tissues are aggregations of similar cells; organs are aggregations of tissues performing specific physiological functions. Organs are organised into organ systems, which work together to form organisms.

Key words

Tissue

Organs

Systems

Multicellular

Muscle

Gland

Epithelial

Digestive

Glands

Pancreas

Salivary glands

Digestive juices

Liver

Bile

Small intestine

Large intestine

Faeces

Roots

Leaves

Stems

Epidermal

Mesophyll

Xylem

Pholem

B2.2.1 Animal organs

a) Large multicellular organisms develop systems for exchanging materials. During the development of a multicellular organism, cells differentiate so that they can perform different functions.

b) A tissue is a group of cells with similar structure and function. Examples of tissues include:

■ muscular tissue, which can contract to bring about movement ■ glandular tissue, which can produce substances such as enzymes and hormones ■ epithelial tissue, which covers some parts of the body.

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c) Organs are made of tissues. One organ may contain several tissues. The stomach is an organ that contains:

■ muscular tissue, to churn the contents ■ glandular tissue, to produce digestive juices ■ epithelial tissue, to cover the outside and the inside of the stomach

Type of tissue General role Role in the stomach organ

Muscular

Glandular

Epithelial

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d) Organ systems are groups of organs that perform a particular function. The digestive system is one example of a system in which humans and other mammals exchange substances with the environment. The digestive system includes:

■ glands, such as the pancreas and salivary glands, which produce digestive juices ■ the stomach and small intestine, where digestion occurs ■ the liver, which produces bile ■ the small intestine, where the absorption of soluble food occurs ■ the large intestine, where water is absorbed from the undigested food, producing faeces. Label the diagram: Use the following terms

Gall Bladder Large intestine Liver Mouth Oesophagus Salivary gland Small intestine Stomach Anus

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B2.2.2 Plant organs

a) Plant organs include stems, roots and

leaves.

b) Examples of plant tissues include:

■ epidermal tissues, which cover the

plant

■ mesophyll, which carries out

photosynthesis

■ xylem and phloem, which transport

substances around the plant.

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Label the leaf section

Use these terms:

Lower epidermis Mesophyll Palisade mesophyll Spongy mesophyll Upper epidermis Wax Cuticle (2)

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GCSE-Style questions: cells, tissues & organs

Q1. The drawing shows the cell of a bacterium.

(a) List A gives the four structures labelled on the diagram.

List B includes information about each structure.

Draw one line from each structure in List A to the correct information about the structure in List B.

List A List B Structure Information

(4)

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(b) Give two differences between an animal cell and the cell of a bacterium.

1 .....................................................................................................................

2 ..................................................................................................................... (2)

(c) The diagrams show cells containing and surrounded by oxygen molecules.

Oxygen can move into cells or out of cells.

Into which cell, A, B, C or D, will oxygen move the fastest?

Write the correct letter, A, B, C or D, in the box. (1)

(d) Complete the following sentence.

Oxygen is taken into the cell by the process of ............................................. (1)

(Total 8 marks)

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Q2. Plants and animals have tissues which carry out different functions.

List A gives three tissues in living organisms.

List B includes information about each tissue.

Draw one line from each tissue in List A to the correct information about the tissue in List B.

List ATissue List BInformation

Transports substances around a plant

Muscular

Covers roots, stems and leaves

Xylem

Contracts to cause movement

Glandular

Produces enzymes

(Total 3 marks)

Q3. Diagram 1 shows a cell from a leaf.

Diagram 1

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(a) How is the leaf cell specialised to carry out photosynthesis?

Tick ( ) one box.

It has a permanent vacuole.

It has many chloroplasts.

It has cytoplasm.

It has many mitochondria.

(1)

(b) Diagram 2 shows another type of plant cell.

Diagram 2

Give two ways in which this cell is different from an animal cell.

1 ..................................................................................................................................

.....................................................................................................................................

2 ..................................................................................................................................

..................................................................................................................................... (2)

(Total 3 marks)

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Q4. The diagram shows a group of muscle cells from the wall of the intestine.

(a) On the diagram, use words from the box to name the structures labelled A, B and C.

cell membrane cell wall chloroplast cytoplasm nucleus

(3)

(b) How are these muscle cells adapted to release a lot of energy?

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 5 marks)

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Q5. The diagram shows a bacterium.

On the drawing, name the structures labelled A, B, C and D. (Total 4 marks)

Q7. The diagram shows a cell from the lining of the lung. This cell is specialised to allow gases to pass through quickly.

(a) Use words from the box to label structures A, B and C.

cell membrane chloroplast cytoplasm mitochondria nucleus

(3)

(b) (i) Which feature of this cell allows oxygen to pass through quickly?

Put a tick ( ) in the box next to your choice.

It is thin.

It has a large nucleus.

It has many mitochondria.

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(ii) Complete the sentence by drawing a ring around the correct answer in the box.

Oxygen passes through this cell by

diffusion

osmosis

respiration

(1)

Q8. The diagrams show a cheek cell from a human and a leaf cell from a plant.

(a) The two cells have a number of parts in common.

(i) On the cheek cell, label three of these parts which both cells have. (3)

(ii) In the table, write the names of the three parts you have labelled above and describe the main function of each part.

Part Function

..................................

..................................

..................................

(3)

(b) Blood contains white cells and red cells. State the function of each type of cell in the blood.

White cells .................................................................................................................

.....................................................................................................................................

Red cells ....................................................................................................................

................................................................................................................................... (2)

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Q9. The diagram shows an animal cell.

(a) Name each labelled part and give its function.

A Name ...............................................................................................................

Function ..........................................................................................................

.........................................................................................................................

B Name ..............................................................................................................

Function .........................................................................................................

........................................................................................................................

C Name ..............................................................................................................

Function .........................................................................................................

........................................................................................................................ (6)

(b) (i) This plant cell also contains chloroplasts, a cell wall and a vacuole. Label each of these parts on the diagram.

(3)

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(ii) Give the function of these parts of a plant cell.

Chloroplast function .........................................................................................

...........................................................................................................................

Cell wall function .............................................................................................

...........................................................................................................................

Vacuole function ..............................................................................................

........................................................................................................................... (3)

(Total 12 marks)

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GCSE-style questions: Digestion

Q1. The diagram shows the digestive system.

For each question write the correct letter in the box.

Which structure, A, B, C, D or E, is:

(a) the stomach (1)

(b) the small intestine (1)

(c) the liver? (1)

(Total 3 marks)

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Q2. The human stomach is an organ.

Describe how the tissues in the stomach enable the stomach to function.

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

.................................................................................................................................

................................................................................................................................. (Total 6 marks)

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Find the odd one out

Identify the odd one out in each of the terms given below and suggest a reason why it is the odd one out. The first one has been done for you

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Make some up of your own and try it out on a partner:

Reason:

Reason:

Reason:

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Blockbusters

Make your own Blockbuster game. Make a list of 20 key words to include on the board. Add the first letter of each word at random on the board. Now compile a set of questions for which each word is the correct answer. Play your game with two others.

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Question Answer

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