Characteristics of Life (MRS GREN)

Question 1

How many characteristics of living organisms are there?

Answer 1

7

Question 2

List all the characteristics of living organisms.

Answer 2

Remember the mnemonic MRS GREN
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition

Question 3

Explain nutrition in green plants.

Answer 3

In green plants, nutrition involves photosynthesis. The plant absorbs energy from sunlight and converts carbon dioxide into water and simple sugars.

Question 4

Define nutrition.

Answer 4

It is when food is used to provide energy and nutrition, which is needed for growth, development and repair.

Question 5

Explain nutrition in animals.

Answer 5

Animals need to eat plants or other animals to obtain energy and nutrients. Food is digested and absorbed, then used by cells for growth and repair.

Question 6

What is ingestion?

Answer 6

The process of taking in food.

Question 7

What is egestion?

Answer 7

Food that has passed through the gut without being digested.

Question 8

What is excretion?

Answer 8

The removal of metabolic waste & substances in excess of the organism’s requirements- not faeces.

Question 9

Explain respiration.

Answer 9

This is when chemical reactions occur in cells to break down nutrients such as the break down of glucose to release oxygen.

Question 10

What is the word equation for respiration involving oxygen?

Answer 10

glucose + oxygen = carbon dioxide + water + energy released

**This energy is used by living organisms for movement, growth, repair & reproduction.

Question 11

Explain movement.

Answer 11

When organisms move themselves or parts of themselves into new areas or to change position. E.g. Plant leaves move up toward the sun during growth.

Question 12

Explain growth.

Answer 12

This is a permanent increase in the size of an organism by an increase in either cell number, cell size or both.

Question 13

Explain metabolism.

Answer 13

All chemical reactions that occur in an organism resulting in the production of toxic waste substances.

Question 14

Explain sensitivity.

Answer 14

The ability to detect & respond to stimuli.
e.g. Plants move leaves & stems toward sunlight. Animals have sensory cells & organs to detect light, sound, touch, pressure & chemicals in the air & food.

Question 15

Explain reproduction.

Answer 15

When organisms reproduce to make new individuals.
e.g. Asexual: 1 parent- offspring identical to each other & parent.
Sexual: 2 parents- gametes which fuse- offspring show variation.