the processes of life Flashcards
what is anaerobic respiration?
obtaining energy when oxygen is in low concentration
where does anaerobic respiration occur?
- vigorous exercise
- plant roots in waterlogged soil
- bacteria in deep puncture wounds
what is the equation for anaerobic respiration in bacteria and animal cells?
glucose —> lactic acid + energy
what is the equation for anaerobic respiration in yeast and plants?
glucose —> ethanol + carbon dioxide + energy
what is respiration?
releasing energy by breaking down large food molecules
what is aerobic respiration?
respiration using oxygen
what is the word equation for aerobic respiration?
glucose + oxygen —> carbon dioxide + water + energy released
what are the factors that limit the rate of photosynthesis?
temperature, carbon dioxide and light intensity
what is the cell membrane?
controls what enters and leaves cells
allows gases and water to pass in and out freely
what is the cytoplasm?
where most chemical reactions in the cell occur
including anaerobic + production of enzymes
what is the nucleus?
contains dna which stores genetic code for making enzymes
what is the mitochondria?
contain enzymes required for the release of energy by aerobic respiration
what is photosynthesis?
use energy from sunlight to build up large food molecules in plant cells and some microorganisms eg phytoplankton
what is the word equation for photosynthesis?
carbon dioxide + water —> glucose + oxygen + energy released
what is osmosis?
overall movement of water from dilute solution to a concentrated solution through partially permeable membrane
allows passage of water but not solute molecules
what is diffusion?
movement of chemicals from a high concentration to a low
it is:
- passive
what happens in photosynthesis?
1) water taken up by plant roots
2) carbon dioxide enters plants, leaves by diffusion
3) oxygen leaves, plant leaves by diffusion
whats the optimum temperature of most enzymes?
37 C
what do ecologists need to do to investigate the effects of light intensity on plant growth?
- measure how common the plants are
- light meter to measure light intensity
- identification key to identify plants found
how is a quadrat put on the ground?
- at random
- a number of times so an average is taken
how do ecologists investigate the abundance and distribution of plants?
- in diff areas + make comparison
- diff locations in area + make comparison
what is a quadrat?
anything with a defined area which is placed at intervals along transect to sample the area
what is a transect?
a line which is used to measure distances by the quadrat if theres an obvious change in the plants in the area
what are enzymes?
chemicals that speed up the rate of reaction
when do enzymes stop working?
if the pH is inappropriate or the temperature is too higher
enzymes need a specific temperature and pH to work at their optimum
which type of respiration releases more energy per molecule of glucose?
aerobic
what is the product of photosynthesis?
give 3 answers
- converted into starch for storage
- used in respiration
- converted to chemicals 4 plants growth eg cellulose, chlorophyll, protein
what are the possible fates of glucose made by photosynthesis?
(give 6 examples)
- cellulose for cell walls
- protein for growth
- starch for energy storage
- oil for energy storage
- make chlorophyll
- respire to give energy
what is active transport?
uses energy from respiration to transport chemicals across a cell membrane
what is the role of minerals taken up by plant roots in active transport?
used to make chemicals essential to cells
eg nitrogen taken up as nitrates used to make proteins
why cant root cells take up nitrates by diffusion?
nitrates are in a higher concentration in plant cells than the soil
what are the uses of anaerobic respiration?
- in yeast used for baking, releasing co2 which makes dough rise
- more energy to cells when necessary
what is the energy released in by respiration used in?
- movement:
contraction of muscles - synthesis of large molecules from smaller ones:
chlorophyll from glucose - active transport
what is the active site?
place where substrate fits in enzyme
how can the shape of the active site be changed?
- heating enzyme above certain temp
- altering pH level
meaning molecule no longer fits + reaction cant take place
if change is permanent, enzyme = denatured
how does photosynthesis take place?
give 3 stages
- light energy absorbed by chlorophyll
- light energy used to rearrange atoms of co2 and h2o to produce glucose
- oxygen = waste
what substances move in and out of cells by diffusion?
3 answers
- oxygen
- dissolved food
- carbon dioxide
what is a cell wall?
made of cellulose to strengthen cell
what is a permanent vacuole?
helps support the cell
what are chloroplasts?
contain chlorophyll and some enzymes for photosynthesis
what does a rise in temperature in photosynthesis do?
rise in temp increases rate of photosynthesis to certain point, the rate then decreases bc of effect of temp on enzyme activity
what does a rise in carbon dioxide and light intensity in photosynthesis do?
if increased, rate of photosynthesis increases + levels off
what do plants use the food produced by photosynthesis for?
- respiration
- active transport
excess glucose stored as starch
