How is food stored?
As glycogen (in liver, muscles) and as fats (adipocytes in adipose tissue under the skin)
What do cells do with food?
Oxidise it, use it for maintenance or store it.
What are the characteristics of living things?
Movement, nutrition, growth, sensitivity to changes in environment, respiration, excretion, reproduction
What are life processes?
The basic functions performed by living organisms to maintain their life on earth
Define nutrition
The process of intake and utilisation of nutrients in and organism
Which is more complex, starch or glucose?
Starch is more complex
Name some types of carbohydrates
Glucose, starch
List the types of heterotrophic nutrition.
Saprophytic, parasitic, holozoic
Saprophytic nutrition
Decaying organic material
What is a parasite?
It is an organism which derives its food from the body of another living organism.
Examples of saprophytic/ saprotrophic.
Fungi ( bread moulds, mushrooms, yeast )
Examples of parasites ( plants )
Cuscuta, rafflesia
Examples of parasites ( animals )
Tape worm, round worm, liver fluke
Equation for photosynthesis
6CO2 + 12H2O + light energy –chlorophyll–> C6H12O6 + 6O2 + 6H2O
Formula for glucose
C6H12O6
Transfer of form of energy during photosynthesis?
Light energy to chemical energy
3 steps of photosynthesis
Absorption of sunlight energy by chlorophyll, conversion of light energy to chemical energy and splitting of H2O by light energy, reduction of CO2 by H2 to obtain carbohydrate by using the chemical energy
Name the type of nutrition observed in plants
Autotrophic
Name a carbohydrate stored in the human body
Glycogen
State the function of chlorophyll in plants
It helps in the fixation of sunlight ( absorbs light e and converts it to chemical e )
Name two forms in which plants take nitrogen
Nitrites, nitrates
List some organisms which break down food outside their body
Rhizopus, agaricus, yeast, mucor
What form of nutrition can be observed in amoeba
Holozoic, phagocytosis
How is food pushed in the alimentary canal
The walls of the alimentary canal have muscles. Rhythmic contractions and relaxations of these pushes forward food ( peristalsis )
How is the lining of the stomach protected from HCl
Presence of mucus
Why do herbivores have a longer small intestine
Herbivores eat plants, therefore their diet mainly consists of cellulose, which takes longer to digest
How is the small intestine suitable for absorption?
It is long, has thin walls that are highly vascular
How long is the small intestine
About 6 m
Give examples of nutrients
Fats, carbohydrates, proteins, minerals, vitamins
How does exchange of gases take place in a single-celled organism?
Via diffusion across the cell membrane
What is the role of bio-catalysts in humans?
Enzymes break down large, insoluble molecules into small, soluble molecules which can be absorbed by the body to produce energy,
How is food stored in plants?
Starch. Glucose is converted to starch for storage
How does a stoma open?
The opening and closing of stomata is controlled by guard cells
When water flows into the guard cells, they swell up and become turgid. They become curved and open the stomata. When the guard cells lose water, they become flaccid. This causes them to shrink and close the stomatal pore
What happens if you chew bread for a very long time
Bread contains starch. When we chew for a long time, the salivary amylase in saliva converts the starch to maltose which tastes sweet.
How does amoeba capture it’s food?
Through the process of endocytosis
State the two functions of stomata
Exchange of gases, transpiration
An experiment that requires KOH
To prove that CO2 is needed for photosynthesis
Why is nitrogen essential for plants
Synthesis of amino acids and proteins
Examples of autotrophs
Plants, Cyanobacteria
Body/biology currency
Adenosine Tri Phosphate
Why is glucose changed to starch?
Because it changed the chemical composition of the cell
Dark reaction
Reduction of CO2 into glucose
Cross section of leaf
Upper epidermis, mesophyll, lower epidermis with stomata
Principle behind proving the need for materials for photosynthesis?
Removing the condition
To prove that sunlight is needed
De-starching, cover one leaf, keep plant in sun, pluck leave, denature enzymes (boil leaf), de-colourising (water bath), dipping in water, iodine
Dark room procedure
Time depending on size of plant, it has to be watered
Why do enzymes have to be de-natured?
They will quickly convert all the starch to sugar
How to denature enzymes?
Boil in water
Why do we de colourise leaves?
So that the blue colour is seen clearly
Why is alcohol used in water baths?
An organic solvent is needed to kill chlorophyll; alcohol has low ignition temperature
Why is the leaf put in water
To soften it, as it becomes brittle and impermeable.
Colour of iodine
Yellowish brown
To check for chlorophyll,
Us a plant with leaves that are only partly green, variegated leaves
Examples of variegated leaves
Crotons, money plant
To check need for CO2
De starch two plants, put them in bell jars, with POH in one
POH
Potassium Hydroxide
Why is POH used?
To remove CO2 from one bell jar.
What is used to seal the bell jar
Vaseline
What was used earlier, instead of Vaseline?
Wax
Flaccid
Very little water
Turgid
Full of water
Why don’t plants use ammonia from the soil?
It is toxic
Parasitic roots
Haustoria
Phagocytosis
In amoeba
Pinocytosis
Water
Phagocytosis
Solid food
Two parts of human digestive system…
Alimentary canal, digestive glands
What do digestive glands do?
Produce enzymes
Features of alimentary canal
It is a long, slightly coiled tube of variable diameter which has two distinct openings
Outside raw materials used by autotrophs
CO2, H2O, solar energy
Define metabolism
All the chemical reactions that take place in a cell
What category of food acts as source of energy in plants?
Carbohydrates
Is the process of photosynthesis anabolic or catabolic
In this reaction, the reactants combine, therefore, it is anabolic
What are the products formed during the break down of H2O?
H+ ions, O2, and 2 electrons per each H2O molecule
Name the two energy rich substances formed during light reactions.
ATP and NADPH
Autotrophic nutrition involves the process of ….. Or……
Photosynthesis, chemosynthesis