6.4: Organisation and Specialisation of Cells

Question 1

What are cells?

Answer 1

The basic unit of life.

Question 2

State the order of size of organic components, starting from smallest.

Answer 2

Organelle, specialised cells, tissues, organsm organ system, organism

Question 3

What does it mean for a cell to be differentiated?

Answer 3

They are specialised to carry out specific functions

Question 4

What are erythrocytes?

Answer 4

Red blood cells

Question 5

How are erythrocytes specialised?

Answer 5

-Flattened bioconcave shape
-Flexible
-Do not contain a nucleus or many other organelles

Question 6

Why do erythrocytes have a bioconcave shape?

Answer 6

To increase their surface area : volume ratio, to increase the rate of diffusion, which allows them to squeeze through blood vessels

Question 7

Why are erythrocytes flexible?

Answer 7

To squeeze through narrow capillaries and blood vessels

Question 8

Why do erythrocytes not contain a nucleus?

Answer 8

To make space for haemoglobin, which binds to oxygen for it to be stored and transported oxygen around the body.

Question 9

What are neutrophils?

Answer 9

A type of white blood cell that plays an essential role in the immune system

Question 10

How are neutrophils specialised?

Answer 10

-Have a multi-lobed nucleus
-Cytoplasm contains many enzymes used to attack pathogens
-Performs phagocytosis

Question 11

Why do neutrophils have a multi-lobed nucleus?

Answer 11

Because it makes it easier for them to squeeze through small gaps, to get to the site of infections.

Question 12

What are sperm cells?

Answer 12

Male gametes.

Question 13

What is the function of sperm cells?

Answer 13

To deliver genetic information to the female gamete

Question 14

How are sperm cells specialised?

Answer 14

-Have tail/flagellum
-Aerosome on head contains digestive enzymes, released to digest the protective layers around the ovum
-Have many mitochondria that contain ATP

Question 15

Why do sperm cells have a tail?

Answer 15

So they are capable of movement

Question 16

Why do sperm cells contain many mitochondria?

Answer 16

To hold ATP, which supplies the energy needed to swim

Question 17

Why do sperm cells have digestive enzymes in the aerosome on their heads?

Answer 17

To digest the protective layers around the ovum, which allows the sperm to penetrate, leading to fertilisation.

Question 18

Where are palisade cells found?

Answer 18

In the mesophyll of a plant

Question 19

How are palisade cells specialised?

Answer 19

-Contain chloroplasts
-Cells are rectangular box shapes
-Have thin cell walls
-Contain large vacuoles
-Chloroplasts can move within the cytoplasm

Question 20

Why do palisade cells contain chloroplasts?

Answer 20

To absorb large amounts of light for photosynthesis

Question 21

Why are palisade cells rectangular box shapes?

Answer 21

So they can be closely packed to form a continuous layer

Question 22

Why do palisade cells have thin cell walls?

Answer 22

To increase the rate of diffusion of CO2

Question 23

Why do palisade cells contain large vacuoles?

Answer 23

To maintain turgor pressure

Question 24

Why can chloroplasts move within the cytoplasm in palisade cells?

Answer 24

To absorb more light

Question 25

Where are root hair cells present?

Answer 25

At the surfaces of roots, near growing tips in a plant

Question 26

How are root hair cells specialised?

Answer 26

-Have long extensions called root hair.

Question 27

Why do root hair cells have root hair?

Answer 27

To increase the surface area of the cell, which maximises uptake of water and minerals from the soil.

Question 28

What do pairs of guard cells form?

Answer 28

Small openings called stomata, found on the surfaces of leaves on a plant.

Question 29

What are stomata necessary for?

Answer 29

Carbon dioxide to enter plants for photosynthesis

Question 30

What happens to guard cells when they lose water?

Answer 30

They become less swollen as a result of osmotic forces, and change shape. The stoma closes to prevent further water loss.

Question 31

Which side of the cell walls of a guard cell is thicker?

Answer 31

The side of the stoma

Question 32

Why is one side of the cell wall of a guard cell thicker?

Answer 32

So the cell does not change shape symmetrically as its volume changes

Question 33

What are the 4 main categories of tissue in animals?

Answer 33

Nervous tissue, epethelial tissue, muscle tissue and connective tissue

Question 34

What is a tissue?

Answer 34

A collection of differentiated cells that have a specialised function. Each tissue is adapted for a particular function within the organism.

Question 35

What is a nervous tissue adapted for?

Answer 35

Supporting the transmission of electrical impulses

Question 36

What is an epithelial tissue adapted for?

Answer 36

Covering body surfaces, internal and external

Question 37

What is muscle tissue adapted for?

Answer 37

Contracting

Question 38

What is connective tissue adapted for?

Answer 38

Either holding other tissues together or as a transport medium

Question 39

What is squamous epithelium tissue?

Answer 39

Animal tissue made up of specialised squamous epithelial cells, also known as "pavement epithelium"

Question 40

What are the features of squamous epithelium tissue?

Answer 40

-Thin (only one cell thick) -Present when rapid diffusion across a surface is essential -Forms the lining of the lungs

Question 41

Why is squamous epithelium tissue one cell thick?

Answer 41

Because of the flat cells that make it up, and to allow rapid diffusion

Question 42

Why does squamous epithelium tissue form the lining of the lungs?

Answer 42

To allow rapid diffusion of oxygen into the blood

Question 43

What is ciliated epithelium tissue?

Answer 43

Animal tissue made up of ciliated epithelial cells

Question 44

What are the features of ciliated epithelium tissue?

Answer 44

-Cells have cillia on one surface -Line the trachea -Goblet cells are also present within the tissue

Question 45

Why does ciliated epithelium tissue line the trachea?

Answer 45

Because the cilia on its surface causes mucus to be swept away from the lungs

Question 46

Why does ciliated epithelium tissue contain goblet cells?

Answer 46

To release mucus to trap any unwanted particles, which prevents them from reaching the alveoli when in the lungs.

Question 47

What is cartilage?

Answer 47

Connective tissue found in the outer ear, nose and at the ends of and between bones

Question 48

What does cartilage contain?

Answer 48

Fibres of elastin and collagen. Composed of chondrocyte cells embedded in an extracellular matrix

Question 49

What are the properties of cartilage?

Answer 49

Firm and flexible

Question 50

What is the function of cartilage in bones?

Answer 50

Prevents the ends of bones from rubbing together and causing damage

Question 51

What is muscle?

Answer 51

Tissue that has to contract to move bones and therefore other parts of the body.

Question 52

What do skeletal muscle fibres contain?

Answer 52

Myofibrils, which contain contractile proteins

Question 53

What are the two types of plant tissue?

Answer 53

Epidermis tissue and vascular tissue

Question 54

What are epidermis tissues?

Answer 54

Plant tissues that are adapted to cover plant surfaces

Question 55

What are vascular tissues?

Answer 55

Plant tissues that are adapted for transport of water and nutrients

Question 56

What is the epidermis?

Answer 56

-A single layer of closely packed cells, covering the surfaces of plants. Usually covered by a waxy, waterproof cuticle to reduce water loss

Question 57

What feature of plants is present in the epidermis, and what is its function?

Answer 57

Stomata, allow carbon dioxide, water vapour and oxygen in and out

Question 58

What is xylem tissue?

Answer 58

Vascular tissue responsible for transport of water and minerals throughout plants.

Question 59

What is xylem tissue composed of?

Answer 59

Vessel elements - Elongated, dead cells. Walls of these cells are strengthened by lignin

Question 60

What is xylem strengthened by?

Answer 60

Walls of the dead xylem cells are strengthened by lignin.

Question 61

What is phloem tissue?

Answer 61

A type of vascular tissue, responsible for transport of organic nutrients from leaves and stems to all parts of the plant where it is needed.

Question 62

What is phloem tissue composed of?

Answer 62

Columns of sieve tube cells, seporated by perforated walls called sieve plates.

Question 63

What is an organ?

Answer 63

A collection of tissues that are adapted to perform a particular function in an organism

Question 64

What is an organ system?

Answer 64

A collection of organs working together to carry out a major function in the body.