Biology Key Concepts: Cells, Respiration, Photosynthesis, and Ecosystems

What is the primary difference between a eukaryotic and a prokaryotic cell?

Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells do not.

What is the process of cell differentiation?

The process by which a cell becomes specialised to carry out a particular function.

How does active transport differ from diffusion?

Active transport moves substances against a concentration gradient using energy (ATP), whereas diffusion moves particles down a concentration gradient.

What is the function of an enzyme?

It acts as a biological catalyst to speed up chemical reactions.

What occurs during the denaturation of an enzyme?

The enzyme changes shape, preventing it from functioning.

What is the difference between aerobic and anaerobic respiration in animals?

Aerobic respiration uses oxygen to produce carbon dioxide and water; anaerobic respiration occurs without oxygen and produces lactic acid.

What is the role of ATP in cells?

It is the molecule that stores and transfers energy.

Where does gas exchange occur in the human lungs?

In the alveoli, which are tiny air sacs.

What is the function of chlorophyll in photosynthesis?

It is a pigment that absorbs light energy.

What is the difference between xylem and phloem?

Xylem transports water and minerals from roots to leaves, while phloem transports sugars around the plant.

What is the difference between embryonic and adult stem cells?

Embryonic stem cells can become any cell type, whereas adult stem cells can only form certain cell types.

What is the function of stomata in leaves?

They are pores that allow for gas exchange.

What is the transpiration stream?

The movement of water from the roots to the leaves.

What factors affect the rate of transpiration?

Light, temperature, humidity, and wind.

What is the difference between abiotic and biotic factors in an ecosystem?

Abiotic factors are non-living (e.g., temperature), while biotic factors are living interactions (e.g., predation).

How does the heart function in a double circulation system?

Blood passes through the heart twice in one complete circuit.

What is the role of memory cells in the immune system?

They remember pathogens and trigger a faster, stronger response upon re-infection.

What is the purpose of vaccination?

To introduce a harmless form of a pathogen to stimulate immunity.

What is the difference between a population and a community?

A population consists of all organisms of one species in a habitat, while a community consists of all populations of different species in an area.

What is the role of decomposition in the carbon cycle?

It breaks down dead material and releases carbon back into the environment.

What is the function of an antibody?

It is a protein that binds to a specific antigen to help fight infection.

What is the difference between pollination and fertilisation?

Pollination is the transfer of pollen from anther to stigma, while fertilisation is the fusion of male and female gametes.