Cells - Cell structure: Cell specialisation and organisation

Question 1

How does a cell become specialised?

Answer 1

Different specialised cells have different genes switched on to suit its function, and the rest are not expressed.

Question 2

Why can an embryonic cell mature into any kind of specialised cell?

Answer 2

The first group of cells in an embryo are initially identical, so all contain the same genes needed for them to develop into any kind of cell.

Question 3

What is the smallest unit of life?

Answer 3

A cell

Question 4

What is a specialised cell?

Answer 4

A cell with additional features that allow it to carry out a particular function.

Question 5

What is a tissue?

Answer 5

A group of similar cells that work together to perform a specific function.

Question 6

Give 2 examples of animal tissues.

Answer 6

Epithelial tissues

Muscle tissue

Question 7

Give 2 examples of plant tissues.

Answer 7

Xylem

Root tissue

Question 8

What kind of functions do epithelial cells have?

Answer 8

Protective or secretory

Question 9

Where are epithelial tissues generally found?

Answer 9

Lining the surface of organs.

Question 10

What is the advantage of cell specialisation?

Answer 10

It allows the whole organism to function more efficiently.

Question 11

What is an organ?

Answer 11

A group of tissues that work together to perform a variety of functions.

Question 12

Give 2 examples of animal organs.

Answer 12

Stomach

Heart

Question 13

Give 2 examples of plant organs.

Answer 13

Leaf

Root

Question 14

What is an organ system?

Answer 14

A group of organs working together to perform a function.

Question 15

Give 3 examples of human organ systems.

Answer 15

Digestive system
Respiratory system
Circulatory system

Question 16

Give an example of a plant organ system.

Answer 16

Transport system

Question 17

What 3 types of tissue is the stomach made up of and what are their functions?

Answer 17

Muscle to churn and mix the stomach contents.
Epithelium to protect the stomach walls and produce secretions.
Connective to hold together the other tissues.

Question 18

What 5 types of tissue is a lead made up of and what are their functions?

Answer 18

Palisade mesophyll (leaf palisade cells) for photosynthesis.
Spongy mesophyll adapted for gaseous diffusion.
Epidermis to protect the leaf and allow gaseous diffusion.
Phloem to transport organic materials away from the leaf.
Xylem to transport water and ions into the leaf.

Question 19

Why are capillaries not organs when arteries and veins are?

Answer 19

Capillaries are made up of just one tissue (epithelium) whereas arteries and veins are made up of many tissues (epithelium, muscle etc)

Question 20

Give 6 of the organs that make up the digestive system.

Answer 20

Salivary glands
Oesophagus
Stomach
Ileum
Pancreas
Liver

Question 21

Give 3 of the organs that make up the respiratory system.

Answer 21

Trachea
Bronchi
Lungs

Question 22

Give 3 of the organs that make up the circulatory system.

Answer 22

Heart
Arteries
Veins

Question 23

6 examples of differentiated cells

Answer 23

erythrocyte (red blood cell)
neutrophil (white blood cell)
squamous epithelial cell
palisade cell
ciliated epithelial cell
root hair cell

Question 24

How are erythrocytes specialised to carry oxygen?

Answer 24

No nucleus or organelles allows more space for haemoglobin protein which binds to oxygen.
Flexible to squeeze down narrow capillaries.
Biconcave disc shape increases surfaces area for gas exchange.

Question 25

How are neutrophils specialised for phagocytosis?

Answer 25

Lobed nucleus allows cell to squeeze through gaps in capillary walls into tissue fluid. Lots of lysosomes to digest engulfed pathogens.

Question 26

How are squamous epithelial cells specialised to allow diffusion and create a smooth surface?

Answer 26

Very thin, flat cells so short diffusion distance. Basement membrane connects to body. Nucleus positioned low down so as not to interfere with diffusion.

Question 27

How are ciliated epithelial cells specialised to move mucus?

Answer 27

Cilia on surface beat to waft sticky mucus across surface. Lots of mitochondria to provide energy for beating. Pathogens trapped in mucus.

Question 28

What produces mucus?

Answer 28

Goblet cells

Question 29

How are palisade cells specialised to carry out photosynthesis in leaves?

Answer 29

Many chloroplasts (containing chlorophyll - where photosynthesis takes place), thin cell walls to allow light in, large vacuole to store products of photosynthesis.

Question 30

How are root hair cells specialised to absorb water and minerals from the soil?

Answer 30

Hair shape increases surface area for absorption, many mitochondria to provide energy for pumping minerals into cell by active transport. Many transport proteins in cell membrane, large central vacuole to store water and minerals.

Question 31

3 ways epithelial cells in the small intestine are specialised to absorb food efficiently.

Answer 31

1) the walls of the small intestine have lots of villi which increase surface area for absorption
2) epithelial cells on surface of villi have folds in their cell-surface membranes called microvilli, further increasing the surface area
3) they have lots of mitochondria to provide energy for the transport of digested food molecules into the cell