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51 Cards in this Set
- Front
- Back
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Name an organism with a prokaryotic cell
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Bacteria
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Name 3 structures which are in plant cells but not animal cells
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Cell wall
Large, central vacuole Chloroplasts (not in all plant cells) |
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Name 3 structures found in animal cells but not in plant cells
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Cilia
Flagella Centrioles |
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What storage polysaccharides are found in:
1) Plants 2) Animals |
1) Starch
2) Glycogen |
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List the metabolic activities carried out by cells
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Anabolic reactions (e.g. protein synthesis)
DNA replication Photosynthesis (plant cells) Catabolic reactions (e.g. to destroy unwanted chemicals Respiration |
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List differences between prokaroytic and eukaryotic cells
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Prokaroyotic cells don't keep all their genetic material inside a nuclear membrane, they have a few internal membranes, their ribosomes are different from eukaryotes
Eukaryotic cells have a nucleus, they have lots of internal membranes |
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Explain what happens when each of these processes are carried out by lysosomes:
~ Autolysis ~ Autophagy ~ Phagocytosis |
Autolysis: destruction of whole cell
Autophagy: descruction of organelles Phagocytosis: destruction of foreign cells (e.g. bacteria |
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Describe one way in which a lysosome is similar to a peroxisome and one way in which it is different
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Both contain chemicals that break down molecules
Lysosomes are formed by budding of vesicles from the Golgi body, but peroxisomes are formed by budding from an existing peroxisome |
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List the functions of the cell membrane
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Separates cells from the external environment
Controls entry and exit of materials into and out of the cell Has receptors for horomones and/or neurotransmitters Has antigens for identification of cell as self or foreign Is an anchor for the internal cytoskeleton Has connectors to anchor it to other cells |
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Describe the structure of the cell membrane
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Phospholipid bilayer with proteins embedded in it, also cholesterol molecules between phospholipid tails
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Describe the functions of each of the components of the cell membrane
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Proteins: function as receptors, channels, transporters, enzymes, linkers, antigens, attachement points for the cytoskeleton
Phosolipids: form the structure of the membrane |
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Is the hydrophilic part of a phospholipid molecule on the outside or the inside of the membrane
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Outside (hydrophobic fatty acid tails on the inside of the membrane)
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Explain the difference between active and passive transport
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Active transport requires energy and passive transport doesn't
Active transport is against the concentration gradient, passive is down the gradient |
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What is the difference between diffusion and faciliated diffusion
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Faciliated diffusion requires the presence of transporter molecules, diffusion dose'nt
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Name substances that can enter cells by diffusion
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Oxygen
C02 (leaving cell) Fat soluble vitamins, Alcohol |
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Name a substance that can enter cells by faciliated diffusion
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Glucose
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Describe the differences between cilia and flagella
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Cells usually have many cilia but only one or 2 flagella
Flagella are usually longer than cilia |
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Name human cells that have:
1) Flagella 2) Cilia |
1) Sperm cells
2) Epitelium in lungs (trachea, bronchi) |
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When are centrioles found and what do they do?
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In the centrosome near the nucleus, from the spindle apparatus needed for cell division
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Explain why red blood cells have a biconcave shape
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The shape provides the cell with a larger surface area.
The larger surface area makes transport of oxygen across the membrane efficent |
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Explain why the walls of alveoli in the lungs are thin
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Thin walls make gas exchange between the blood and the interior of the alveolus efficent
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Compare osmosis and diffusion listing similarities and differences
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Simliar: both involve passive diffusion down a concentration gradient
Different: Osmosis moves water molecules only and requires a semi-permeable membrane, diffusion involves other molecules and doesn't require a semi-permeable membrane |
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What do the prefixes hypo, hyper and iso mean
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Hypo: below
Hyper: above Iso: the same |
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Draw plasmolysed plant cell and explain what plasmolysed means
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The cell membrane has been pulled away from the cell wall because water has been withdrawn from the cytoplasm by osmosis
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Why are turgid cells important in lettuces?
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It makes the lettuce crisp instead of limp
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Name an example of an ion pump
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Sodium potassium pump in nerve membranes
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Explain the difference between phagocytosis and pinocytosis
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Both are a form of endocytosis, the process in which a membrane surrounds an object and brings it into the cell.
Phagocytosis involves solid materials (e.g. bacteria) Pinocytosis involves liquids |
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Name 3 types of cells that use exocytosis
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Endocrine cells producing hormones
The ends of axons where neurotransmitters are released into the synapse Cells in a mucous membrane producing mucus |
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Why do cells need energy?
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For anabolic reactions, active transport, producing movement (e.g. muscle contractions, flagella and cilia), homeothermy (in birds and mammals)
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What is cellular respiration?
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A set of chemical reaction that produce ATP
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Give two reasons why anaerobic respiration in inefficent
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It produces very little energy
It products are toxic |
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Name carrier molecules for hydrogen ions, energy and acetyl (2 carbon) groups
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Hydrogen ions: NAD and FAD
Energy: ADP Acetyl (2 carbon) groups: coenzyme A |
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Write an equation for aerobic respiration
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Glucose + oxygen = carbon dioxide + water + energy
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Write an equation for the manufacture of ATP to ADP
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ADP + P + energy = ATP
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Write an equation for alcohol fermentation
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Glucose = ethanol + carbon dioxide
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Describe 3 features of the nuclear membrane
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It's double membrane
It has pores Is continuous with the endoplasmic reticulum It may have ribosomes on it |
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What's the name for the material inside the nucleus and what are it's chemical constituents?
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Chromatin and DNA and proteins
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Describe what the nucleus does?
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It contains the genetic material
Genetic material is a set of instructions that tells cells how to behave (what chemical reactions do) The nucleus is often described as a control centre |
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Where are chromosomes visable?
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Only during cell divison
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How many chromosomes are found in human cells?
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Every cell (apart from red blood cells and gametes) has 46 chromosomes
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What is the purpose of mitosis
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To produce new cells for growth and to allow for repair of damaged tissues or to replace cells (e.g. skin or gut)
Damaged cells are not repaired by mitosis- they die and are replaced by new cells |
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Name the stages of mitosis
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Interphas
Prophase Metaphas Anaphase Telophase Cytokinesis |
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How many chromosomes are found in a new cell formed by mitosis
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The same number as in the original cell
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Describe the 3 molecules that make up a nucletide
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A sugar molecule
A nutrogenous base Phosphate ion |
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Name the 4 bases found in DNA
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Adenine (A)
Guanine (G) Cytosine (C) Thymine (T) |
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What are the base pairing rules?
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A with T
G with C |
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Describe a molecule of DNA
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DNA is a polymer made from nucleotides
Is double stranded and takes the form of a double helix The sides of the helix are alternate sugar/phosphates held together by strong convalent bonds The bases are geld together by weak hydrogen bonds Adenine always pairs with Thymine Guanine always pairs with cytosine The two chains are arranged in a anti-parrallel manner |
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Describe how a DNA molecule is wound into a chromosome
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The molecule is wound onto proteins called histones and then histones are wound into a spiral
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Describe the steps in DNA replication
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Enzymes unwind the helix and the hydrogen bonds holding the base pairs together break
Each of the original strands acts as a template for the formation of a new strand Base pairing ensures that the appropriate nucleotide is incorporated into the new chain An enzyme called DNA polymerase is required |
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When is DNA replicated?
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Before cell division so that each new cell have a set of chromosomes
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Why is replication described as semi-conservtive
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Each molecule of DNA keeps one old stand and has one newly synthesised strand
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