Digestion and Surface Area Essays

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2.3 Obtaining nutrients – Questions and answers

Q1.
Bk Ch2 S2.3 Q1
Define the following terms, and provide examples of each: a tissue b organ c system.

A1.
Bk Ch2 S2.3 A1
Tissues are groups of similar cells that work together to perform a particular function. Example: muscle tissue in the lining of the stomach.
An organ is a group of different tissues that work together to perform a particular function. Example: the stomach is an organ composed of muscle tissue, epidermal tissue and vascular tissue.
A system is a group of organs that work together to perform a particular function. Example: the digestive system includes such organs as the stomach and intestine.

Q2.
Bk Ch2 S2.3 Q2
Cell specialisation in multicellular organisms is an adaptation that allows all of the organism’s requirements to be met. Complete this table, showing some different kinds of specialised cells in multicellular organisms and their functions.

Cell type
Plant/animal
Diagram
Function
How structure relates to function
Nerve cell

Lining cell of small intestine

Root hair cell

Leaf mesophyll cell

A2.
Bk Ch2 S2.3 A2

Cell type
Plant/animal
Diagram
Function
How structure relates to function
Nerve cell
Animal

Carries nerve impulses from one part of body to another
Extension of cytoplasm allows impulses to be carried over long distances
Lining cell of small intestine
Animal

Absorbs nutrients
Villi (of folded cell membrane) increase surface area of cell, maximising absorption
Root hair cell
Plant

Absorbs mineral nutrients from soil
Extension of cell increases surface area, enhancing efficiency of absorption
Leaf mesophyll cell
Plant

Carries out photosynthesis
Contains many chloroplasts, which increases the amount of glucose produced in photosynthesis

Q3.
Bk Ch2 S2.3 Q3
Distinguish between the autotrophic and heterotrophic nature of plants and animals.

A3.
Bk Ch2 S2.3 A3
Plants are autotrophic organisms, that is, they are ‘self-feeding’; the green cells of plants contain chloroplasts which photosynthesise, producing their own organic nutrients. Animals are heterotrophic; they cannot produce their own nutrients and so rely on eating plants or other animals that eat plants in order to obtain organic materials.

Q4.
Bk Ch2 S2.3 Q4
Explain the following statement: ‘All living things depend on plants.’

A4.
Bk Ch2 S2.3 A4
All living things need organic materials as a source of energy. Organic substances are produced by plants in the process of photosynthesis. Animals do not photosynthesise and so rely on plants to obtain these materials. Animals either eat plants directly or eat other animals that eat plants.

Q5.
Bk Ch2 S2.3 Q5
Write out the word equation that summarises the process of photosynthesis.

A5.
Bk Ch2 S2.3 A5 carbon dioxide + water sugar + oxygen

Q6.
Bk Ch2 S2.3 Q6 a Compare aquatic and terrestrial plants in relation to the site of water and mineral uptake. b Terrestrial plants need a large surface area in order to maximise water uptake. How is this achieved?

A6.
Bk Ch2 S2.3 A6 a Aquatic plants generally have their entire bodies submerged in the water. Such plants can absorb water and minerals from their external environment directly into their bodies across the plant surface. Terrestrial plants obtain water and minerals from the soil through their root systems. b The root systems of terrestrial plants are extensive and their surface area is further enhanced by the presence of root hairs, which are the site of water uptake. This large surface area increases the efficiency of absorption by terrestrial plants.

Q7.
Bk Ch2 S2.3 Q7
Explain how the structure of typical leaves and the distribution of specialised tissue within them is an adaptation to photosynthesis. Use clearly labelled diagrams in your answer.

A7.
Bk Ch2 S2.3 A7
The structure of leaves is an adaptation to…