B1 Flashcards
Are light microscopes cheap or expensive ?
Relatively cheap
How do light microscopes work?
They use a beam of light to form the image of an object.
How much can a light microscope magnify?
They magnify things several thousand times.
How do electron microscopes work and what is they’re max magnification.
They use a beam of electrons to form an image and can magnify images up to two million times.
What are the two types of electron microscopes and explain what both are ?
Transmission electron microscopes give 2D images but very high magnification and resolution.
Scanning electron microscopes give 3D images but lower magnifications.
What type of cell makes up the body ?
Animal cells
What is a nucleus and what does it do?
A nucleus controls all the activities of the cell and is surrounded by the nuclear membrane. it contains the genes on the chromosomes that carry the instructions for making proteins needed to build new cells or new organisms. The average diameter is around 10 μm.
What is a cytoplasm and what does it do?
It is a liquid gel in which the organelles are suspended and where most of the chemical reactions need for life take place.
What is a cell membrane and what does it do?
It lies on the outside of a cell and it controls the passage of substances such as glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.
What is mitochondria and what does it do?
It structures the cytoplasm where aerobic respiration takes place, releasing energy for the cell. They are very small: 1-2 um in length and only about 0.2-0.7 um in diameter.
What are ribosomes and what do they do?
They are where protein synthesis takes place, making all the proteins needed in the cell.
How do plants make their food ?
By photosynthesis
TRUE or FALSE…
Plant cells have all the features of an animal cell
TRUE
What are chloroplasts and what do they do?
Chloroplasts are found in all the green parts of a plant. They are green because they contain the green substance chlorophyll. Chlorophyll absorbs light so the plant can make food for photosynthesis. Each chloroplast is around 3-5um long. Root cells do not have chloroplasts because they are underground and do not photosynthesise.
What is a permanent vacuole and what does it do?
It is a space in the cytoplasm filled with cell sap. This is important for keeping the cells rigid to support the plant.
What cell parts do eukaryotic cells have?
They have a cell membrane, cytoplasm, genetic material that is enclosed in a nucleus and mitochondria.
What is genetic material?
It is a chemical called DNA and this forms structures chromosomes that are contained within the nucleus.
TRUE OR FALSE…
All animals including human beings, fungi, plants, and protista are eukaryotes.
TRUE
What cell parts do prokaryotic cells have? (give an example of a prokaryote)
Bacteria are single-celled living organisms. They are examples of prokaryotes. They are around 0.2-2.0 um in length.
Bacteria have a cytoplasm and a cell membrane surrounded by a cell wall, but the cell wall does not contain the cellulose you see in plant cells.
TRUE OR FALSE…
In prokaryotic cells, the genetic material is enclosed in a nucleus
FALSE
The bacterial chromosome is a single DNA loop found free in the cytoplasm.
What are plasmids, where are they found and what do they do?
Plasmids are found in some prokaryotic cells. They are an extra small ring of DNA. They code for very specific features such as antibiotic resistance.
What is a slime capsule, and where is it found?
Some bacteria have a protective slime capsule around the outside of the cell wall.
What are flagella, where is it found, and how can it be used?
Some type of bacterium has at least one flagellum (plural: flagella), that is, a long protein strand that lashes about and can help the bacterium move.