Term
| How do we improve the reliability of the results of an experiment? |
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Definition
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Term
| Why do we repeat experiments? |
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Definition
| To improve the reliability of the results |
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Term
| How do we improve the validity of an experiment? |
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Definition
| By improving its design. For example, having all the reagents at the same temperature to start with, making sure that all conditions are the same (controlled variable) except for what is changed (independent/input variable). |
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Term
| Why do we use % or % change as a way to compare results? |
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Definition
| To allow comparison between tissues which were different in their mass/ volume/ length at the start of the experiment. |
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Term
| Why do we use different pipettes/syringes/measuring cylinders |
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Definition
| To prevent cross-contamination of solutions of different concentrations. |
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Term
| 1-Why do we use a microscope? |
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Definition
| to magnify an object so it appears larger than it is |
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Term
| 2-More powerful lenses allow you to see more/less of the sample |
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Definition
| Less but in greater detail |
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Term
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Definition
| So that cell parts stand out |
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Term
| 4-Why do we use coverslips? |
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Definition
| So that the sample does not dry out |
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Term
| 5-To convert 1 mm into 1 μm (micrometer)… |
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Definition
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Term
| 6-To convert 1 μm into 1 mm |
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Definition
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Term
| 7-To calculate the total power of the microscope |
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Definition
| Multiply the power of the eyepiece lens and the power of the objective lens |
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Term
| 5-Function of cell membrane |
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Definition
| Controls the movement of substances into and out of the cell. |
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Term
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Definition
| Where most chemical processes take place. |
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Term
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Definition
| Contains genetic material which controls the activities of the cell. |
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Term
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Definition
| Contains cell sap and can help keep cell structure rigid. |
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Term
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Definition
| Where protein synthesis happens |
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Term
| 10-Function of mitochondria |
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Definition
| Where most of the energy is released by respiration |
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Term
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Definition
| It strengthens and supports the cell. |
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Term
| 12-Function of chloroplast |
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Definition
| Contain the pigment chlorophyll. Photosynthesis happens here. |
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Term
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Definition
| Circular piece of DNA in bacteria. |
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Term
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Definition
| Area where bacterial DNA is found. |
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Term
| 15-Similarity/ difference between plant and fungal cell |
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Definition
| Similar structures except that plant cell wall is made of cellulose and fungi have no chloroplasts. |
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Term
| 16-Similarity/ difference between animal and fungal cell |
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Definition
| Similar structures except that animals cells have neither cell walls nor vacuoles. |
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Term
| 17-Plant cell wall structure compared to fungal and bacterial cells |
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Definition
| Only plant cell wall is made of cellulose. |
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Term
| 18-Difference between prokaryotic and eukaryotic cells |
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Definition
| Prokaryotic cells don’t have a membrane-bound nucleus, e.g. bacteria. |
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Term
| 2-Property of the cell membrane |
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Definition
| It is selectively permeable (only let molecules smaller than a certain size go through) |
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Term
| 3-Characteristics of passive transport |
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Definition
| Passive transport happens down a concentration gradient and does not require energy. |
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Term
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Definition
| The molecules which form the cell membrane move constantly with respect to each other. |
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Term
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Definition
| Diffusion in cells as the movement of molecules down a concentration gradient, from an area of high concentration to an area of low concentration |
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Term
| 6-Importance of diffusion |
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Definition
| It is how gases (CO2, O2) and some other substances, e.g. water, glucose, urea and amino acids move in and out of cells; O2 and glucose are needed by animal cells for respiration; |
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Term
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Definition
| Osmosis as the movement of water molecules down a concentration gradient through a selectively permeable membrane. |
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Term
| 8-Effect of osmosis on animal cells |
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Definition
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Term
| 9-Effect of osmosis on plant cells |
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Definition
| Water loss: cells plasmolysed (cell shrinks away from the cell wal, cell wall caves in) |
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Term
| 10-In experiments, the diffusion of substances is usually demonstrated by… |
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Definition
| A reagent changing colour. |
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Term
| 11-In experiments, osmosis is usually demonstrated by… |
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Definition
| A change in mass of a piece of potato or a model cell or a change of volume (on a graduated tube) |
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Term
| 12-Define active transport |
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Definition
| Transport against the concentration gradient |
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Term
| 13-Requirements for active transport |
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Definition
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Term
| 14-Examples of molecules and organisms using active transport |
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Definition
| Transport of sodium and potassium in nerve cells, or iodine in seaweeds. |
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Term
| 1-State the function of cell division |
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Definition
| To increase the number of cells in an organism so that growth and cell replacement/repair can take place. |
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Term
| 2-State the biological name for cell division |
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Definition
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Term
| 3-State what is the store of hereditary information? |
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Definition
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Term
| 4-What is meant by “chromosome complement”? |
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Definition
| Number of chromosomes characteristic to a species, e.g. humans have 46 chromosomes |
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Term
| 5-Describe how the daughter cells compare to the original cell |
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Definition
| They have an identical set of chromosomes which carry the same information as the original cell. |
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Term
| 6-Explain why it is important that the chromosome complement of daughter cells in multi-cellular organisms is maintained |
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Definition
| If cells don’t inherit exactly the same set of chromosomes (e.g. too many or too few), they do not behave as any other cell and die or grow and/or function abnormally. |
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Term
| What is meant by a “diploid cell” |
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Definition
| Diploid cells have two matching sets of chromosomes. |
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Term
| 1-Why is cell culture done? |
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Definition
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Term
| 2-What is needed for cell culture? |
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Definition
| Cell production by cell culture requires aseptic techniques, an appropriate medium and the control of other factors (e.g. availability of oxygen, temperature, pH) |
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Term
| 3-Explain how glassware can be sterilised |
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Definition
| heat glassware in an autoclave (pressure cooker) to 121oC |
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Term
| 4-Explain how hands and surfaces need to be prepared before an experiment. |
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Definition
| - Hands need to be washed before an experiment to remove microorganisms from skin. |
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Term
| 5-Explain how microbes can be prevented to contaminate an opened petri dish |
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Definition
| hold lid over open petri dish |
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Term
| 6-Explain how the inoculating can be sterilized? |
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Definition
| Flame the inoculating loop. |
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Term
| 7-Why are lids held onto inoculated petri dishes with tape |
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Definition
| To prevent entry OR exit of microbes from agar. |
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Term
| 1-Describe the structure of a DNA molecule. |
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Definition
| Double stranded/ double helix. |
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Term
| 2-What holds the DNA strand together? |
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Definition
| A bond between the sugar of one nucleotide and the phosphate of the adjacent nucleotide. |
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Term
| 3-What type of bond holds the two strands together? |
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Definition
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Term
| 4-What is determined by the base sequence? |
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Definition
| The genetic code. In proteins, the base sequence determines amino acid sequence. |
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Term
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Definition
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Term
| 1-What are the chemical elements found in proteins? |
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Definition
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Term
| 2-Structure of proteins is determined by… |
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Definition
| DNA sequence which itself determines the order of amino acids. |
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Term
| 3-Name of the type of bond holding between amino acids |
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Definition
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Term
| 4-Give 5 examples functions of proteins |
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Definition
| Enzymes: speed up chemical reactions. |
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Term
| 5-Where does protein synthesis take place? |
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Definition
| In ribosomes in the cytoplasm. |
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Term
| 6-What carries the sequence information from where it is stored (i.e. in the nucleus) to where it is needed (ribosome) |
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Definition
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Term
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Definition
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Term
| 1- Describe a chemical reaction in general terms |
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Definition
| A substrate is chemically altered into a product |
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Term
| 2- Explain the meaning of the term “catalyst”. |
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Definition
| A catalyst is a substance which speeds up the rate (i.e. the speed) of a chemical reaction without being changed or used up. |
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Term
| 3-State what an enzyme is. |
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Definition
| An enzyme is a biological catalyst made up by all living cells. It speeds up reaction are is left unchanged. |
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Term
| 4-Which part of the enzyme binds to the substrate? |
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Definition
| The active site. The shape of the active site is complementary to its specific substrate. |
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Term
| 5-Explain the word “specific” as applied to enzymes and their substrate |
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Definition
| Each enzyme only works on one substrate because the shape of the active site is only complementary to its specific substrate. E.g. Amylase only breaks down starch. Enzymes and substrates have matching shapes like a “lock and key”. |
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Term
| 6-Explain why enzymes are required for the functioning of living cells. |
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Definition
| The cell processes necessary for life would happen too slowly without enzymes. |
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Term
| 7-Give an example of an enzyme involved in a degradation reaction. |
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Definition
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Term
| 8-Give an example of an enzyme involved in synthesis (building up) |
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Definition
| Potato phosphorylase: in potatoes, joins molecules of Glucose-1-phosphate to form starch. |
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Term
| 9-State what type of molecule enzymes are. |
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Definition
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Term
| 10-Describe the effect of temperature on enzyme activity |
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Definition
| At low temperatures, enzymes do not work effectively (molecules move too slowly). Enzymes increase the rate of reaction (i.e. speed up) most effectively at a temperature called the optimum. Beyond that temperature, the shape of the enzyme and its active site change slowing down reaction rate. Above a certain temperature, an enzyme becomes denaturated, i.e. it is irreversibly damaged |
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Term
| 11-Describe the effect of a range of pH on the activity of pepsin and catalase |
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Definition
| Each enzyme has a specific pH, i.e. a pH at which it works most effectively (faster rate of reaction). Enzyme may work at other pH but the rate of the chemical reaction that they control is usually not as fast. |
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Term
| 12-Explain the term “optimum” as applied to the activity of enzymes |
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Definition
| The conditions at which enzymes works best are called optimum conditions: optimum pH and optimum temperature. |
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Term
| 13-Explain what a control is. |
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Definition
| A repeat of an experiment to show that the effect observed is only due to the factor being investigated (e.g. activity of an enzyme) |
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Term
| 1-State in general terms how genetic information can be transferred |
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Definition
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Term
| 2-Give examples of natural genetic engineering |
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Definition
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Term
| 3-State in general terms how human can engineer bacteria to make new substances |
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Definition
| By transferring a piece of chromosome from another organism to bacteria. |
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Term
| 5-State what is the advantage of genetic engineering for the production of substances from genes |
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Definition
| Obtain large quantities in short time. |
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Term
| 6-Give examples of products of genetic engineering used by humans |
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Definition
| Insulin to help treat diabetes. |
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Term
| 1-Word equation of photosynthesis |
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Definition
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Term
| 2-Number of stages and their name |
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Definition
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Term
| 3-Description of first stage |
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Definition
| The light energy from the sun is trapped by chlorophyll in the chloroplasts and is converted into chemical energy in the form of ATP. |
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Term
| 4-Description of second stage |
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Definition
| A series of enzyme-controlled reactions which use hydrogen and ATP (produced by the light reactions) with carbon dioxide to produce sugar. |
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Term
| 5-Explain the transfer of energy from the light arriving at the leaf to the formation of sugar. |
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Definition
| Light energy is trapped by chlorophyll. |
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Term
| 6-What are the elements found in a carbohydrate? |
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Definition
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Term
| 7-What are the 3 fates of the glucose produced by photosynthesis? |
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Definition
| - used directly in respiration to provide energy for cell processes. |
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Term
| 8-How are factors affecting starch usually investigated? |
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Definition
| By testing leaves with starch. |
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Term
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Definition
| Name of a green pigment found in chloroplasts which captures light energy. |
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Term
| 10-Describe the process of photosynthesis in terms of raw materials and products. |
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Definition
| Raw materials: carbon dioxide and water |
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Term
| 11-Explain what is meant by a limiting factor and describe the main limiting factors in the process of photosynthesis. |
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Definition
| Something which, when in short supply, will slow down or stop photosynthesis resulting in the decrease of growth. |
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Term
| 1-State 5 reasons why living cells need energy. |
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Definition
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Term
| 2-Give an example of an energy transformation in a plant and in an animal. |
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Definition
| Plants: light energy → chemical energy (starch) |
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Term
| 3-State what cells need in order to release the energy from food. |
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Definition
| Cells need oxygen (found in air) to release the energy from food in “aerobic respiration” |
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Term
| 4-Describe aerobic respiration in terms of a word equation |
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Definition
| glucose + oxygen → energy + carbon dioxide + water |
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Term
| 5-What is produced by all respiring animals and plants? |
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Definition
| Carbon dioxide and water. |
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Term
| 6-What is the link between energy producing and energy demanding reactions? |
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Definition
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Term
| 7-Write the equation of ATP breakdown and regeneration |
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Definition
| Breakdown: ATP → ADP + Pi : releases energy, Regeneration: ADP +Pi → ATP : requires energy,(Pi stands for inorganic phosphate) |
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Term
| 8-How many ATPs are regenerated during aerobic respiration? |
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Definition
| 38 ATP per molecule of glucose. |
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Term
| 9-Breakdown of ATP production during aerobic respiration |
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Definition
| 2 ATP are produced when glucose is broken down into 2 molecules of pyruvic acid in the cytoplasm. |
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Term
| 10-Which cells need lots of mitochondria? |
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Definition
| Cells with high energy needs such as muscle cells, nerve cells, sperm cells. |
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Term
| 11-State what is produced by respiration in addition to carbon dioxide |
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Definition
| Heat energy and water will be produced by aerobic respiration. |
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Term
| 12-Give another word for anaerobic respiration in plants and yeast |
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Definition
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Term
| 13-Characteristic of anaerobic respiration |
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Definition
| It takes place in the absence of oxygen. |
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Term
| 14-Where does anaerobic respiration take place and how many ATPs does it release? |
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Definition
| Only in the cytoplasm, 2 ATP molecules. |
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Term
| 15-Products of anaerobic respiration in plants and yeast (fungi) |
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Definition
| Ethanol and carbon dioxide. |
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Term
| 16- Products of anaerobic respiration in animals |
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Definition
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Term
| 17-State which of these types of food contains more energy per gram: proteins, fats, carbohydrates. |
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Definition
| Fats contain about twice as much energy as proteins and carbohydrates (sugars, starch) |
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Term
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Definition
Animal cell:
1-mitochondrion, 2-cell membrane, 3-cytoplasm, 4-nucleus, 5-ribosomes. |
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Term
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Definition
Plant cell:
1-cell wall, 2-mitochondrion, 3-chloroplast, 4-cell membrane, 5-cytoplasm, 6-vacuole, 7-nucleus, 8-ribosomes. |
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Term
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Definition
| 1-cell membrane, 2-cell wall, 3-ribosome, 4-nucleoid, 5-cytoplasm, 6-plasmid |
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Term
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Definition
Fungal cell (e.g. yeast)
1-cell wall, 2-mitochondrion, 3-cell membrane, 4-cytoplasm, 5-vacuole, 6-nucleus, 7-ribosome. |
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