Biology · Cell Biology
Cell Structure
What is inside plant, animal and bacterial cells, how to see them with a microscope, how cells become specialised, and how bacteria are grown safely in the laboratory. Matches AQA Biology topic 4.1.1, and the cell structure sections of Edexcel topic 1 and OCR module B1. The last lesson, Culturing Microorganisms, is separate Biology only.
Lessons
Ticks are remembered on this device only.
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1
Eukaryotic and Prokaryotic Cells
Every living thing is made of cells, but not every cell is built the same way. This lesson compares eukaryotic cells with prokaryotic cells such as bacteria…
10 terms -
2
Animal and Plant Cells
Animal and plant cells are eukaryotic, so they share a nucleus and several other structures. This lesson names each sub-cellular structure, says what it does…
10 terms -
3
Microscopy and Magnification
Most cells are too small to see without help. This lesson covers how light and electron microscopes work, how to use a light microscope, and how to calculate…
9 terms -
4
Cell Specialisation and Differentiation
A human body has about 200 different types of cell, and each is built for its own job. This lesson looks at how specialised cells are adapted, and how a cell…
10 terms -
5
Culturing Microorganisms
Bacteria can be grown in the laboratory to study them and to test which chemicals kill them. This lesson covers how bacteria multiply, how an uncontaminated…
12 terms
Key terms in this chapter
All 51, gathered from every lesson.
- Eukaryotic cell
- A cell whose genetic material is enclosed in a nucleus, such as an animal or plant cell.
- Prokaryotic cell
- A cell with no nucleus, whose genetic material lies free in the cytoplasm, such as a bacterium.
- Nucleus
- The part of a eukaryotic cell that contains the genetic material and controls the cell's activities.
- Cytoplasm
- The jelly-like substance inside a cell where most chemical reactions happen.
- Cell membrane
- A thin layer around the cell that controls what enters and leaves.
- Cell wall
- A rigid layer outside the cell membrane that supports the cell. In plants it is made of cellulose.
- Plasmid
- A small ring of DNA, separate from the main loop, found in bacteria.
- Standard form
- A way of writing very large or very small numbers as \(A \times 10^{n}\), where A is between 1 and 10.
- Order of magnitude
- A factor of ten. One order of magnitude is 10 times, two is 100 times.
- Micrometre (µm)
- One millionth of a metre, the unit most cells are measured in.
- Sub-cellular structure
- A structure inside a cell, such as the nucleus or a mitochondrion.
- Mitochondria
- Structures where aerobic respiration takes place, releasing energy for the cell.
- Ribosome
- A tiny structure where proteins are made.
- Chloroplast
- A structure in plant cells that contains chlorophyll and carries out photosynthesis.
- Chlorophyll
- The green pigment that absorbs light energy for photosynthesis.
- Permanent vacuole
- A space in a plant cell filled with cell sap.
- Cell sap
- A solution of sugars and salts stored in the permanent vacuole.
- Cellulose
- The strong material that plant cell walls are made of.
- Aerobic respiration
- A chemical reaction that uses oxygen to release energy from glucose.
- Photosynthesis
- The process in which plants use light to make glucose.
- Magnification
- How many times bigger an image is than the real object.
- Resolution
- The ability to see two points that are close together as separate. Also called resolving power.
- Light microscope
- A microscope that uses light and glass lenses to magnify a specimen.
- Electron microscope
- A microscope that uses a beam of electrons, giving much higher magnification and resolution.
- Eyepiece lens
- The lens you look through, usually ×10.
- Objective lens
- The lens just above the specimen, giving different magnifications.
- Stage
- The platform on which the slide is placed.
- Stain
- A coloured chemical, such as iodine, that makes parts of a cell easier to see.
- Specimen
- The object being looked at under a microscope.
- Specialised cell
- A cell that has a structure suited to its particular job.
- Differentiation
- The process by which a cell changes to become specialised.
- Adaptation
- A feature of a cell that helps it carry out its function.
- Acrosome
- The part of a sperm cell that contains enzymes to break into the egg.
- Axon
- The long extension of a nerve cell that carries impulses.
- Myelin sheath
- A fatty layer around a nerve cell's axon that insulates it and speeds up impulses.
- Root hair cell
- A cell on the surface of a root with a long projection that absorbs water and minerals.
- Xylem
- Tubes made of dead cells that carry water and mineral ions up a plant.
- Phloem
- Living tubes that carry dissolved sugars around a plant.
- Tissue
- A group of similar cells that work together to do a particular job.
- Culture
- A population of microorganisms grown in controlled conditions in the laboratory.
- Binary fission
- The way bacteria multiply: one cell divides into two identical cells.
- Mean division time
- The average time a bacterium takes to divide into two.
- Agar
- A jelly, containing nutrients, that bacteria are grown on in a Petri dish.
- Nutrient broth
- A liquid containing the nutrients that bacteria need to grow.
- Aseptic technique
- Methods used to prevent unwanted microorganisms contaminating a culture.
- Inoculate
- To transfer microorganisms onto the agar or broth.
- Colony
- A visible group of bacteria growing together on agar.
- Antibiotic
- A medicine that kills or stops the growth of bacteria.
- Antiseptic
- A chemical applied to skin or wounds to kill bacteria.
- Disinfectant
- A chemical used on surfaces and objects to kill microorganisms.
- Clear zone
- An area on an agar plate where no bacteria have grown, because of an antibiotic or antiseptic.