40 Questions
What is the first step in the break-down of glucose?
Break-down of glucose into a three-carbon molecule called pyruvate
Where does the break-down of pyruvate using oxygen take place?
Mitochondria
What is the by-product of anaerobic respiration in yeast?
Ethanol and carbon dioxide
What happens when there is a lack of oxygen in muscle cells?
Pyruvate is converted into lactic acid
What is the end product of aerobic respiration?
Water and carbon dioxide
How many carbon atoms are in a pyruvate molecule?
3
What is the term given to the process that takes place in the absence of air (oxygen)?
Anaerobic respiration
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration releases more energy, anaerobic respiration releases less energy
Why is the plant kept in a dark room for three days?
To allow the plant to use up all its starch
What happens to the colour of the leaf when it is dipped in boiling water and then alcohol?
It becomes colourless
What is the purpose of dipping the leaf in a dilute solution of iodine?
To test for starch in the leaf
What can be concluded about the presence of starch in various areas of the leaf?
Starch is present only in the non-green areas of the leaf
What is the primary function of stomata in leaves?
To facilitate gaseous exchange for photosynthesis
Why do plants close their stomata when they do not need carbon dioxide for photosynthesis?
To prevent water loss
What is true about the exchange of gases in plants?
It occurs across the surface of stems, roots, and leaves
What is the purpose of tracing the green areas of the leaf on a sheet of paper?
To compare with the starch test results
What is a common evidence people think of to determine if something is alive?
Visible movement
What is a characteristic of living organisms?
Well-organised structure
Why do living organisms tend to break down over time?
Due to the effects of the environment
What is a reason why there is a controversy about whether viruses are truly alive?
They don't show molecular movement
What is necessary for life, according to professional biologists?
Invisible molecular movement
What can be seen in plants that are alive?
Various colours and growth
Why is it not enough to use visible movement as the defining characteristic of life?
Because some animals can breathe without visible movement
What is true about the organisation of living structures?
They are always well-organised
What is the main function of the villi in the small intestine?
To absorb digested food into the bloodstream
What happens to the unabsorbed food in the small intestine?
It is sent into the large intestine
What is the cause of dental caries or tooth decay?
Bacteria acting on sugars producing acids
What is the role of saliva in preventing dental caries?
It helps to neutralise the acid
What is the purpose of brushing teeth after eating?
To remove plaque from the teeth
What happens if dental caries is left untreated?
Microorganisms may invade the pulp, causing inflammation and infection
What is the function of the anal sphincter?
To regulate the exit of waste material
What is the role of the blood vessels in the villi?
To take the absorbed food to each and every cell of the body
What is the function of the urinary bladder?
To store urine until the pressure leads to the urge to pass it out
What happens when the urinary bladder is expanded?
The pressure of the expanded bladder leads to the urge to pass it out
What is the function of the urethra?
To pass out urine
Why are kidneys vital organs for survival?
Because they remove waste products from the body
What happens when there is restricted blood flow to the kidneys?
The kidneys become less active
What is the purpose of an artificial kidney?
To remove nitrogenous waste products from the blood through dialysis
What is the characteristic of the dialysing fluid used in an artificial kidney?
It has the same osmotic pressure as blood, except that it is devoid of nitrogenous wastes
What is the function of the tubes in an artificial kidney?
To allow the patient's blood to pass through and remove nitrogenous waste products
Study Notes
Photosynthesis
- To demonstrate photosynthesis, keep a plant in a dark room for three days to use up starch, then keep it in sunlight for six hours.
- Pluck a leaf, mark the green areas, and trace them on paper.
- Dip the leaf in boiling water, then in a beaker containing alcohol, and heat until the alcohol boils.
- Observe the color change of the leaf and the solution.
- Dip the leaf in a dilute solution of iodine to test for starch.
- Compare the color of the leaf with the tracing done earlier to conclude about starch presence in various areas.
Stomata
- Stomata are tiny pores on the surface of leaves where massive amounts of gaseous exchange take place for photosynthesis.
- Gaseous exchange occurs across the surface of stems, roots, and leaves as well.
- Plants close stomata when they don't need carbon dioxide for photosynthesis to prevent water loss.
Life Processes
- Living organisms are well-organized structures that can break down over time due to environmental effects.
- Molecular movements are necessary for life to maintain order and organization.
- Viruses do not show molecular movement, which is why there is controversy about whether they are truly alive.
Nutrition
- Autotrophic nutrition and heterotrophic nutrition are two different types of nutrition.
- Plants obtain raw materials for photosynthesis from air, water, and soil.
Respiration
- Respiration breaks down glucose into carbon dioxide and water, releasing energy.
- Anaerobic respiration occurs in the absence of oxygen and produces ethanol and carbon dioxide.
- Aerobic respiration occurs in the presence of oxygen and produces water and more energy.
- Lactic acid builds up in muscles during sudden activity, causing cramps.
Excretory System
- Urine is stored in the urinary bladder until the pressure leads to the urge to pass it out through the urethra.
- The bladder is muscular, so it is under nervous control, allowing us to control the urge to urinate.
- Kidneys filter out nitrogenous waste products from the blood.
- Artificial kidneys can be used in case of kidney failure to remove waste products through dialysis.
This quiz is about an experiment to demonstrate photosynthesis in plants. It involves keeping the plant in darkness, then exposing it to sunlight, and finally observing the changes in the leaf.
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