GCSE Biology B1: Cells and Organisation

These flashcards cover key concepts, definitions, and processes related to GCSE Biology B1 Cells and Organisation.

What are organelles common to animal and plant cells?

Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes.

What are extra organelles in plant cells?

Cell wall, chloroplasts, permanent vacuole.

What is the function of the nucleus?

Controls cell activities and contains DNA.

What are eukaryotic cells?

Cells with a nucleus (animal and plant cells).

What are prokaryotic cells?

Bacterial cells with no nucleus.

One structure bacteria have that animal cells do not?

Circular DNA or plasmids.

What does specialised mean in cells?

A cell adapted to carry out a specific function.

How is a sperm cell adapted?

Tail for movement, many mitochondria, streamlined shape.

How is a nerve cell adapted?

Long axon to transmit electrical impulses.

How is a root hair cell adapted?

Large surface area for water absorption.

How are palisade cells adapted?

Many chloroplasts for photosynthesis.

What is diffusion?

Net movement of particles from high to low concentration.

Does diffusion need energy?

No.

One factor affecting rate of diffusion?

Temperature or concentration gradient.

What is osmosis?

Movement of water across a partially permeable membrane from high to low water concentration.

What is a dilute solution?

High water concentration, low solute concentration.

What is turgor?

Pressure of cell contents against the cell wall.

What happens in a concentrated solution?

Cell becomes plasmolysed.

What is active transport?

Movement of substances against a concentration gradient using energy through respiration.

Example of where active transport happens?

Root hair cells absorbing mineral ions.

Why are exchange surfaces thin?

Short diffusion distance.

One feature of alveoli?

Large surface area.

What is the aim of the potato chip osmosis experiment?

To investigate the effect of sugar solution concentration on osmosis.

What is the independent variable in the potato chip osmosis experiment?

Concentration of sugar solution.

What is the dependent variable in the potato chip osmosis experiment?

Percentage change in mass of potato.

What are the control variables in the potato chip osmosis experiment?

Size of potato chips, time, temperature, volume of solution.

What does no mass change in potato experiments show?

Isotonic solution.

Percentage change formula

Percentage change in mass=initial mass- final mass/initial mass​×100

Why do we plot percentage change

Percentage change is used because samples start with different masses, allowing a fair comparison and improving validity.

Hypotonic

higher water concentration than the cell, so water enters the cell by osmosis.

Hypertonic

lower water concentration than the cell, so water leaves the cell by osmosis.