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45 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the equation for magnification? |
Size of image / size of real object |
I M R |
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What do light microscopes magnify up to? What is there resolving power? |
Magnify up to x2000 Resolving power 200 nm |
Gggggv |
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What do electron microscopes magnify up to? What is there resolving power? |
Magnify up to x2 000 000 Resolving power of 0.2nm |
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What do animal cells contain? |
Nucleus- controls activity of cell and holds dna Cytoplasm - liquid gel in which organelles are suspended, chemical reactions take place Cell membrane- controls what goes in or out of the cell Mitochondria- structures in cytoplasm where aerobic respiration takes place Ribosomes- where protein synthesis takes place |
Ygh |
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What is inside of plant cells? |
Everything in animal cell + Chloroplasts- contain chlorophyll which absorbs light Permanent vacuole- place in the cytoplasm that is filled with cell sap, keeps the cell rigid Cell wall- wall around cell made of cellulose, strength |
Ggg |
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What is a eukaryotic cell? |
Cells that have a cell membrane, cytoplasm and a nucleus which contains genetic material |
Ggg |
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What is a prokaryote? |
Prokaryotic cells consist of cytoplasm and a cell membrane surrounded by a cell wall. The genetic material is not in a distinct nucleus. It forms a single dna loop. Prokaryotes may contain one or more extra small rings of dna called plasmids. Bacteria are examples of prokaryotes. |
Hbg |
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What do nerve cells do? |
The are specialised to carry electrical impulses around the body of an animal. They provide a rapid communication system between different parts of the body |
Hggg |
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What adaptations do nerve cells have? |
-lots of dendrites to make connections to other nerve cells -an axon that carries the nerve impulse from one place to another -synapses are adapted to pass the impulse to another cell or between a nerve cell and a muscle in the body using special transmitter chemicals |
Cvg |
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What do muscle cells do? |
Muscle cells are specialised cells that can contract and relax. Striated muscle cells work together in tissues called muscles. Muscles contract and relax in pairs to move the bones of the skeleton, so vertebrates can move in land and water and fly. |
Vvv |
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What adaptations do muscle cells have? |
-they contain special proteins that slide over each other making the fibres contract -they contain many mitochondria to transfer the energy needed for the chemical reactions to take place as the cells contract and relax -they can store glycogen, a chemical that can be broken down and used in cellular respiration by the mitochondria to transfer the energy needed for the fibres to contract |
Gvc |
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What adaptations do sperm cells have? |
-a long tail whips from side to side to help move the sperm through water or the female reproductive system -the middle section is full of mitochondria, which transfer the energy needed for the tail to work -the acrosome stores digestive enzymes for breaking down the outer layers of the egg -a large nucleus contains the genetic information to be passed on |
Ggg |
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How are root hair cells adapted? |
-they greatly increase the surface area available for water to move into the cell -they have a large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell -they have many mitochondria that transfer the energy needed for the active transport of mineral ions into the root hair cells |
Ggg |
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How are photosynthetic cells adapted? |
-They contain specialised green structures called chloroplasts containing chlorophyll that trap the light needed for photosynthesis -They are usually positioned in continuous layers in the leaves and outer layers of the stem of a plant so they absorb as much light as possible -They have a large permanent vacuole that helps keep the cell rigid as a result of osmosis |
Gggg |
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How are xylem cells adapted? |
-The xylem cells are alive when they are first formed but a special chemical called lignin builds up in spirals in the cell walls. The cells die and form long hollow tubes that allow water and mineral ions to move easily through them, from one end of the plant to another -The spirals and rings of lignin in the xylem cells make them very strong and help them withstand the pressure of water moving up the plant. They also support the plant stem |
Vhf |
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How are phloem cells adapted? |
-The cell walls between the cells break down to form special sieve plates. These allow water carrying dissolved food to move freely up and down the tubes to where it is needed -Phloem cells lose a lot of their internal structures but they are supported by companion cells that help to keep them alive. The mitochondria of the companion cells transfer the energy needed to move dissolved food up and down the plant in phloem |
Hhh |
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What is diffusion? |
The spreading out of particles of any substance, in solution or a gas, resulting in net movement from an area of high concentration to low concentration, down a concentration gradient |
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Name five subcellular structures that both plant and animal cells have |
-cell membrane -nucleus -mitochondria -cytoplasm -ribosomes |
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What three things do plant cells have that animal cells don’t? |
-cellulose cell wall -vacuole -chloroplasts |
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Where is genetic material found in animal cells? Bacterial cells? |
Animal = nucleus Bacterial = floating around in cytoplasm / plasmids |
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What type of organisms are bacteria - prokaryotic or eukaryotic? |
Prokaryotes |
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Which gives a higher resolution - light microscope or electron microscope? |
Electron microscopes |
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What is cell differentiation? |
The process by which a cell changes to become specialised for its job |
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Give three ways that a sperm cell is adapted for swimming to an egg cell |
-Has a long tail to help it move -Has a streamlined head -Has lots of mitochondria to have the energy needed to swim |
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Why is a nerve cell the shape that it is? |
-They are long to cover more distance -They have branched connections to connect to other nerve cells and form a network throughout the body |
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What are chromosomes? |
Chromosomes contain genetic information. They are coiled up lengths of dna molecules |
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What is the cell cycle? |
Body cells in multicellular organisms divide to produce new cells as part of a series of stages called the cell cycle 1. DNA is spread out into long strings 2.The cell grows and increases the amount of subcellular structures 3. DNA duplicates 4.The chromosomes line up at the centre of the cell and cell fibres pull them apart 5. Membranes form around each of the sets of chromosomes (nucleus of new cell) 6. Finally the cytoplasm and cell membrane divide |
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What is mitosis used for by multicellular organisms? |
Mitosis is used to grow or replace cells that have been damaged |
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What is the name of the process by which bacteria divides? |
Binary fission |
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What is the maximum temperature that microorganisms should be grown at in a school lab? Why? |
25 degrees because harmful pathogens can grow above this temperature |
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Give three ways in which you can make sure an experiment testing the effect of antibiotics on bacteria has not been contaminated |
-Petri dish and culture medium are sterilised before use to kill any unwanted microorganisms -After transferring the bacteria, the lid of the Petri dish should be lightly taped on - to stop microorganisms from the air getting in -Petri dish should be stored upside down - to stop drops of condensation falling onto agar surface |
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Give two ways that embryonic stem cells could be used to cure diseases |
-They can be used to replace faulty cells in sick people -You could make insulin producing cells for people with diabetes -You could make nerve cells for people paralysed by spinal injuries |
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Why might some people be opposed to the use of human embryos in stem cell research? |
Some people are against stem cell research because they feel that human embryos shouldn’t be used for experiments since each one are a potential human life |
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What is diffusion? |
Diffusion is the spreading out of particles from an area of higher concentration to and area of low concentration |
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Name three substances that can diffuse through cell membranes, and two that can’t. |
Can: -glucose -amino acids -oxygen Can’t: -proteins -starch |
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What type of molecules move by osmosis? |
Water molecules |
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What are the two main differences between active transport and diffusion? |
-Active transport requires energy -Active transport is going from a low concentration to a high concentration |
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Give three adaptations of exchange surfaces that increase the efficiency of diffusion |
-they have a thing membrane so substances only have a short distance to diffuse -they have a large surface area so lots of a substance can diffuse at once -exchange surfaces in animals have lots of blood vessels to get stuff in and out of the blood quickly |
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Give two ways that the villi in the small intestine are adapted for absorbing digested food |
-They have a single layer of surface cells -They have a very good blood supply to assist quick absorption |
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Explain how leaves are adapted to maximise the amount of carbon dioxide that gets into their cells |
-The flattened shape of the leaf increases the area of this exchange surface -Under the lead is covered in holes called stomata which the carbon dioxide diffuses through -The guard cells control the size of the stomata to let the least amount of co2 out |
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What is a tissue? |
A group of similar cells that work together to perform a particular function |
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Explain what is meant by the term organ system |
A group of organs working together to perform a particular function |
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Why can enzymes be described as biological catalysts |
They reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in the body |
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Why do enzymes only usually catalyse one reaction? |
Because, for the enzyme to work, the substrate has to fit into its active site. If the substrate doesn’t match the enzymes active site, then the reaction won’t be catalysed. |
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What does it mean when an enzyme has been denatured? |
If the enzyme gets too hot, some of the bonds holding it together break. This changes the shape of the enzymes active site, so the substrate won’t fit anymore |
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