Biology · OCR Paper 1
Cell Structures
The structures inside eukaryotic and prokaryotic cells and what each one does, how light and electron microscopes are used to see them, and how to calculate magnification and real size. Matches OCR GCSE Biology A (Gateway Science) B1.1 (cell structures). Every lesson is for both Combined Science and separate Biology, at Foundation and Higher.
Lessons
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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
Key terms in this chapter
All 29, 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.