B1
State two characteristics of living organisms.
Answer (any two):
Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition
Name one structure found in all animal and plant cells.
Answer (any one):
Cell membrane
Cytoplasm
Nucleus
Define the term “organism”.
An organism is an individual living thing.
State the function of the cytoplasm in a cell.
Answer:
It is the site where most chemical reactions take place.
State the term used to describe each of the following levels of organisation:
A group of similar cells working together → Tissue
A group of organs working together → Organ system
Answer ;
A group of similar cells working together → Tissue
A group of organs working together → Organ system
State two differences between eukaryotic and prokaryotic cells.
Answer (any two):
Eukaryotic cells have a nucleus, prokaryotic cells do not.
Eukaryotic cells have organelles, prokaryotic cells do not.
Eukaryotic cells are usually larger; prokaryotic cells are smaller.
Prokaryotic cells include bacteria, eukaryotic cells include plant and animal cells.
Explain the difference between growth and movement as characteristics of living organisms.
Answer:
Growth is a permanent increase in size or mass of an organism.
Growth occurs due to an increase in cell number and/or cell size.
Movement is a change in position or place of the whole organism or part of it.
Movement may be slow (e.g. plant growth towards light) or fast (e.g. animals moving).
Describe how the structure of a root hair cell is adapted for its function. Give three adaptations
Answer (points may include):
Long, hair-like extension gives a large surface area.
Thin cell wall allows short diffusion distance.
Large vacuole helps maintain a concentration gradient.
Many mitochondria provide energy for active transport of minerals.
Explain why the statement “Plants do not move, so movement should not be a characteristic of living organisms” is incorrect.
Answer (points may include):
Plants do show movement, but it is usually slow.
Growth movements occur, such as shoots growing towards light.
Roots grow towards water and gravity.
Movement does not have to involve the whole organism moving from place to place.
Therefore, movement is still a valid characteristic of living organisms.
Explain why some parts of the cell are hard to see and how using a stain helps. State two reasons
Answer (any two):
Some parts of the cell are transparent, so they are hard to see.
Stains colour specific parts of the cell.
This increases contrast, making the parts easier to see.
The image is therefore clearer and more visible.