GCSE Biology- B4 bioenergetics

photosynthesis balanced equation

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Respiration balanced equation

C6H12O6 + 6O2 -> 6CO2 + 6H2O

plant organs

roots, stems, leaves, flowers

stomata

Small openings on the underside of a leaf through which oxygen and carbon dioxide can move

guard cells

control the opening and closing of stomata

waxy cuticle

prevents water loss

upper epidermis

the part of the leaf above the palisades layer that prevents the loss of water

lower epidermis

protective layer on the bottom of leaf which contains stomata & guard cells

spongy mesophyll

layer of loose tissue found beneath the palisade mesophyll in a leaf

palisade mesophyll

layer of cells under the upper epidermis of a leaf

photosynthesis

chemical reaction where glucose is made for respiration.

limiting factor

factors that stop a reaction from reaching its optinum

limiting factors for photosynthesis

light intensity, carbon dioxide concentration and temperature

what happens after optimum temperature in photosynthesis?

enzymes start to break down

what happens when the distance between the pondweed and light increases?

rate of photosynthesis decreases because less bubbles

trachea

Allows air to pass to and from lungs

bronchus

one of the two tubes that connect the lungs with the trachea

alveoli

air sacs in the lungs

lung

An organ found in air-breathing vertebrates that exchanges oxygen and carbon dioxide with the blood

diaphragm

Large, flat muscle at the bottom of the chest cavity that helps with breathing

removal of carbon dioxide

carbon dioxide produced in respiration reaction -> diffuses in bloodstream -> travels to the alveoli -. diffuses into alveoli space -> exhaled into enviroment

why do organisms need energy?

movement, keeping warm, chemical reaction

aerobic respiration equation

glucose + oxygen -> carbon dioxide + water

aerobic respiration

the process where glucose reacts with oxygen to release energy to be used in the body.

anaerobic respiration

Respiration that does not require oxygen

amount of energy released by anaerobic respiration compared to aerobic

5% compared to aerobic

oxygen debt

the amount of oxygen which must be taken in to convert all the lactic acid to carbon dioxide.

Anaerobic respiration equation

glucose --> lactic acid + energy

anaerobic respiration in plants

Glucose --> ethanol + carbon dioxide

anaerobic respiration in yeast

Glucose --> ethanol + carbon dioxide (fermentation)

uses of glucose

respiration, storage (starch), lipids, cellulose, protein synthesis

light intensity equation

Light intensity = 1/(distance)^2

anaerobic respiration symbol equation

C6H12O6 -> 2C3H6O3

anaerobic respiration in plants symbol equation

C6H12O6 -> 2C2H5OH + 2CO2

is respiration endothermic or exothermic

Exothermic - transfers energy to the environment

test for starch

Iodine solution

-Positive:Blue black

-Negative:Orange yellow

why boil leaf in photosynthesis experiment?

to break down the cell membrane for the iodine to enter

why soak leaf in ethanol?

to remove the chlorophyll to not impact colour of iodine

why wash the leaf in warm water?

to soften leaf

Muscle cell adaptations

lots of mitochondria to give more energy for aerobic respiration

muscle tissues

made up of protein fibres that contract when energy is transferred in respiration

glycogen

Storage form of glucose in animals

what do muscle store glucose as?

glycogen, which can be converted to glucose easily

how oxygen reaches muscles

• heart rate increase -> oxygenated blood pumped faster to the muscle cells

• breathing rate + breath volume increase -> increase volume of oxygen entering the blood

what happens when more oxygen reaches muscles

• heart rate increase -> more blood -> more oxygen -> more glucose -> more respiration -> more energy for contractions -> - more carbon dioxide removed -> less likely to fatigue

• more oxygen -> more respiration -> more energy -> more carbon dioxide removed -> oxygen debt

Metabolisim

the sum of every chemical reaction that takes place in a cell or in the organism

metabolism reactions

breakdown of proteins in the liver to urea, formation of lipid molecules, converting glucose into glycogen, proteinsynthesis using nitrate ions, photosynthesis, respiration

rate of metabolism factors

genetics, age, sex, exercise, proportion of muscle to fat or (body) mass (BMI)

sources of blood travel from liver to filter

heart and small intestine

what does the liver do with carbohydrates?

breaks it down as glucose and used for respiration again or stored as glycogen

substances the liver synthesises

blood plasma proteins, cholesterol, vitamin D, bile

how does the liver deal with toxins?

turns it into non-toxic substance or isolated and excreted

role of bile

breaks down fats, neutralise stomach acids, destroy harmful microbes

how does stored glycogen provide glucose to respiring cells in the body?

by turning glycogen back to glucose and diffusing it into bloodstream to other parts of the body.

what is glucose stored as when it is broken down from a lactic acid?

glycogen

how does the liver deal with lactic acid?

by oxidising it into carbon dioxide and water or converting it back to glucose