biology

Topics: Oxygen, Carbon dioxide, Photosynthesis Pages: 5 (782 words) Published: June 30, 2014
Aerobic Respiration

Breaking down glucose to release energy
Products are Carbon dioxide and water

Diffusion is … the movement of molecules from a region of high concentration to a low concentration until the concentration is equal.

Role of a human circulatory system:
Diffuse In – oxygen (O2), dissolved food (glucose) and water (H2O) Diffuse Out – carbon dioxide (CO2),waste and water(H2O)

Respiration – releasing energy in cells
Breathing – getting air into and out of your body

Exercise

When you exercise your heart rate and breathing rate increases Heart rate measured – beats per min.
Breathing rate – counting the number of breaths in a min.

Muscle cells respire faster. Meaning- they need more oxygen and glucose and release more carbon dioxide. A faster breathing rate means that oxygen can be taken into the body at a faster rate and carbon dioxide can be released faster.

Cardiac output = stroke volume x heart rate

Effects of exercise:

Ventilation – breathing
Respire – release of energy from food/chemicals

Anaerobic respiration

… is release of glucose without using oxygen. This produces lactic acid.
glucose = lactic acid + energy

Advantage: useful for muscles because it can release energy to allow muscles to contract when the heart/lungs can't deliver (O2) and glucose fast enough for aerobic respiration. Disadvantages: Lactic acid is not removed from the body. It builds up in the body and the blood. (2) – Anaerobic respiration releases less energy than aerobic respiration.

Lactic acid:
poisonous
causes cramp
causes oxygen debt
EPOC = excess post oxygen consumption means if someone exercises hard you will see their breathing and heart rate will take time to return to a normal resting rate. Photosynthesis ….. is the process where plants use to make glucose.

In this process light energy used to combine with carbon dioxide and water .

Word equation= carbon dioxide + water = glucose + oxygen

SO.. Where does photosynthesis occur?

is a complex series of reactions
they are catalysed by enzymes in organelles called chloroplast light energy is the substance in the process and is absorbed by a green substance in the chloroplasts green substance is called chlorophyll

Chlorophyll converts light energy into chemical energy.
What do pants use glucose for?
respiration (in the mitochondria) = releases energy
stored as carbohydrates e.g. starch

Cross section of a leaf:

Chlorophyll in Chloroplasts captures light energy needed in photosynthesis. The stomata in the leaf surface allows CO2 to diffuse into the leaf. Also allows O2 and H20 produced by photosynthesis to diffuse out of the leaf.

Limiting factors..... limits the growth or development an organism,population or process

4 limiting factors involved in photosynthesis

light
temperature
carbon dioxide
water

Measure the effect of :

1) temperature = using warm or cold baths
2) carbon dioxide = concentration by adding different amounts of sodium hydrogen carbonate to the water 3) light intensity = using bright or dim lights

Water transport

Water and substances dissolved in the water transported in to the plant around the vein. Vein contains tissues called xylem and phloem.

Plant:

glucose is converted into sucrose which is transported in the phloem to the rest of the plant. Water and dissolved minerals travel in the xylem to the rest of the plant. Water and dissolved minerals enter the plants through the roots.

Transpiration:

evaporation of water vapour from the leaves
draws water out from the leaf cells and xylem
draws water up the xylem to from the roots
causes water to enter the roots by osmosis

Types of transport:

active transport
diffusion
osmosis

Osmosis..... is the special case of diffusion Meaning= is the net movement of the water molecules from a region to a higher concentration to a lower concentration...
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