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
Describe the adaptations of a cell specialised for transporting oxygen in the blood
State the formula used to calculate magnification
What type of DNA do bacteria have?
Circular DNA
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.
Describe the adaptations of a leaf cell specialised for photosynthesis.
What is 1 mm equal to?
1 mm =0,1 cm
1 mm = 1000 µm)
Explain why specialised cells have different shapes even though they all contain similar basic structures.
: They are adapted to perform different functions, so their shapes and structures change to suit their specific roles.
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.
Describe the adaptations of a cell specialised for transmitting electrical impulses
Explain why units must be converted before calculating magnification or actual size.
Explain why an increase in cell size makes diffusion less efficient.
As a cell gets larger, its volume increases faster than its surface area, reducing the surface area to volume ratio and slowing diffusion.
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).
State the function of ribosomes in a cell.
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.
A microscope image of a cell is 40 mm long. The magnification is ×400. Calculate the actual size of the cell.
Actual size = 40 mm ÷ 400
Actual size = 0.1 mm
Actual size = 100 µm
explain why bacteria can reproduce quickly compared to multicellular organisms.
They are single cells and divide rapidly by binary fission
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.
Describe the adaptations of a male gamete cell
An image of a bacterium is 12 mm long. The actual length of the bacterium is 3 µm. Calculate the magnification.
Convert 12 mm to micrometres: 12 mm = 12 000 µm
Magnification = image size ÷ actual size
Magnification = 12 000 µm ÷ 3 µm
Magnification = ×4000
A root hair cell dies. Explain why the plant may still temporarily absorb water.
Water can still enter by diffusion/osmosis, but mineral ion uptake by active transport stops.