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54 Cards in this Set
- Front
- Back
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what is ATP used for?
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to store and release energy for chemical reactions occuring within the cells.
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how does organisms obtain energy for cellular processes?
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take energy rich compounds such as glucose int the cell and in the presence of enzymes break them down to release potential energy
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cells like sperm and muscle cell undertake active transport what does this mean
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has a high energy requirement thus have a lot of mitochondria
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what does chloroplasts contain?
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chlorophyll that absorbs sunlight for photosynthesis
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what are factors limiting the rate of photosynthesis?
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light intensity, carbon dioxide concentration, temperature
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what are enzymes?
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biological catalysts whuch lower the activation energy (minimum energy needed for reaction to occur) by providing an alternative reaction pathway
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how does temperature affect enzymes?
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rate of reaction increases as temperature is raised. best at optimum temp. over temp enzymes are denatured as bonds holding proteins together breaks and structure of enzyme changes
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what is the purpose of DNA replication?
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it is where the DNA in the cell makes an exact copy of itself prior to cell division so that there is a full set of genetic information available in each cell after division has occured.
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what does semi conservative mean?
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is when each molecule of DNA that is created contains one old strand and one new strand
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what are factors that affect the rate of mitosis?
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temperature, pH, mutagens e.g radiation, availability of raw materials in the cell.
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when are the stages which mitosis occur at a higher rate?
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periods of growth and repair
eg. infacy, childhood, early developments in animals e.g seasonal growth in plants e.g damage to the organism when repair of tissue is needed. |
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what locations is the rate of mitosis the fastest?
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places where most growth or replacement of cells is occuring
e.g. root/shoot tips, hair follicles, skin cells etc mitosis rates also increase in areas of cellular repair and site of damage and also in cancer cells |
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what is the purpose of aerobic respiration? what is it needed for?
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to release energy from energy rich molecules (food) with the presence of oxygen.
metabolism, growth, movement etc. |
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what is the chemical eqn for aerobic respiration?
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C6H12O6+O2→6CO2+6H2O+38ATP
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where does aereobic reaction takes place?
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in the mitochondria
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What is diffusion?
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the spread of particles through random motion from regions of higher cncentration to regions of lower concentration until they are equal.
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what is osmosis?
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is the movement of water across a partially (semi) permeable membrane from an area of high water concentration to a low water concentration until they are equal.
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enzymes function in specific conditions, what would happen if they are outside of the conditions?
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they will not function as well
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what happens when enzymes go beyond optimum temperature?
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enzymes may become denatured which makes them inactive and this latter reaction is irreversible
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what happens when enzymes are denatured?
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shape/structure of the active site is changed thus substrates can no longer fit for reactions to occur.
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what happens when the active site is distorted?
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rate of photosynthesis will decrease as not many interactions will be able totake place. if enzymes are denatured, rate of photosynthesis will decrease rapidly and may stop altogether.
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what is the process of replication?
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-the two strands seperate, exposing the bases (unwound by the enzyme helicase), which will act as a template for the formation of two new stands.
-free nucleotides are matched up with their complementary bases on each of the seperated strands. -new nucleotides join up following the base pairing rule A-T and C-G. -DNA polymerase enzyme directs this. -nucleotides can only be added at the 3' end of a polynucleotide chain -leading strand can be copied directly but lagging strand has to be built in sections (okazaki fragments) that are joined together. |
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what does the outer membrane of the mitochondria do?
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regulates the passage of materials in and out of the organelle
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what does the inner mitochondria?
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it is compartmentalised into numerous cristae, which expands its surface area thereby enchancing its ability to produce ATP.
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mitochondria from cells that have a greater demand for ATP e.g muscle cells have even more what?
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cristae
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what is the matrix in the mitochondria?
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It's the fluid-filled space enclosed by the inner membrane, containing many enzymes, which can function on the large surface area created by the cristae.
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how does number of mitochondria vary by organism or tissue?
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there are more in animals than in plants.
some just have one, others more (muscles) , even up to thousands (liver) |
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how is variation in number related to the energy requirements of the particular cells? (mitochondria)
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the higher the energy demand; the greater the number of mitochondria
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Leaves are....
what is the epidermis? |
-leaves are flat and thin.
-the epidermis is usually transparent (lacks chloroplasts) and coated on the outer side with a waxy cuticle that prevents water loss which would decrease the rate of photosynthesis. |
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where is the location of cells containing most chloroplasts?
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found near the top of the leaf (palaside) in long cylindrical cells, with the chloroplasts close to the walls of the cell. These factors combine and lead to more light being recieved where it can be used to maximise the rate of photosynthesis.
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what does the slight separation of the cells provide? (leaves)
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maximum absorption of CO2
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what is beneath the palisade layer? (leaves)
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Spongy mesophyll. the cells of the spongy layer are more rounded and not so tightly packed. there are large intercellular air spaces which maximises the rate of diffusion of gases during photosynthesis (CO2 enters, O2 leaves)
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what does specialized guard cells mainly in the lower epidermis function?
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controlling the movement of gasses and waterloss.
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how is the organelle chloroplasts structured to maximize the rate of photosynthesis?
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-flat stacks called thylakoids have an increased surface area for the absorption of light
-stroma is a clear fluid which doesn't block the light -chloroplasts have thin membranes/large surface area for absorption of light |
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what does the combination of cells and organelles structure in leaves do?
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helps to keep photosynthesis at its maximum potential rate.
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how does concentration of enzymes affect rate of reaction?
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the higher the concentration the faster the rate of reaction
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how does the substrate concentration affect rate of reaction?
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as the conc substrate increase, rate of reaction increases until the there are no more active sites available. when extra substrate is added it will make no difference until some of the active sites become available.
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what is active transport? what are the two types?
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movement of particles (Na, Mg, glucose) from a low concentration to a high concentration where energy is needed as it's going against concentration gradient.
carrier proteins, cytosis |
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what are carrier proteins?
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move molecules from one side of the membrane to the other. e.g sugars, amino acids, Na, K, Ca
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what is endocytisis?
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transporting molecules across (not in or out) a cell membrane by forming a vesicle from the cell membrane.
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what happens at interphase?
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the cell is engaged in metabolic activity and prepares for mitosis. chromatins at this stage thus not clearly visible.
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what is the acronym PMAT?
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-Prophase
-Metaphase -Anaphase -Telophase |
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what happens at prophase?
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DNA condenses and supercoils into chromosomes. has 2 chromatids joined by centromere and each chromatid is a copy of the original chromosome. nuclear membrane disappears.
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what is metaphase?
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chromosomes line up randomly at the cell equator. a spindle network of fibers has formed across the cell to control the division.
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what happens in anaphase?
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chromatids of each chromosome get torn apart by the spindle network and are moved towards the poles.
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what is telaphase?
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the spindle fibre network retracts and a nuclear membrane forms around each set of chromosomes. the chromosomes start to coil and dissappear from view.
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what are the factors affecting rate of diffusion?
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2 main factors:
- steepness of the concentration of gradient. bigger the diff between conc on the two sides of a membrane, the quicker the rate of diffusion -temperature. higher the temp the more kenetic energy the molecules or ions have. -others are SA, type molecule e.g bigger means slower as more energy needed, distance travelled e.g. shorter the faster |
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what is cytosis? bulk enters? bulk removed?
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movement of large/bulk quantities molecules in and out of cells.
endocytosis. exocytosis. |
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what is pinocytosis? phagocytosis?
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cell drinking (uptake liquids)
cell eating (solids) |
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what are inhibitors? co-enzymes?
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changes shape of enzyme.
assists enzyme to function properly. |
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what is exocytosis?
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substances made inside cell is released to the outside of the cell (in a vesicle).
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what is mitosis?
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cell division for growth and repair where it produces two identical saughter cells
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what is thr chemical equation for photosynthesis?
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6H2O+6CO2→C6H12O6 + 6O2
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what happens at the end of DNA replication?
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2 new molecules of DNA made which are exact copies of the original. it winds up again to form a double helix where it is attached at the centromere.
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