GSCE Biology Chapter 9

What is cellular respiration?

An exothermic reaction continuosly occurring in living cells . The energy transferred supplies all the energy needed for living organisms.

What is the aerobic respiriation equation?

Glucose + Oxygen → Carbon Dioxide + Water

What is the chemical symbol for glucose?

CH₆H₁₂O₆

How do Mitochondria enable respiriation?

The organelles are found in almost all plant and animal cells and have a folded inner membrane which provides a larger surface area for enzymes. The number of mitochondria indicate how active the cell is.

What do living cells use respiration for?

The basic functions of life:

• build up large molecules from smaller ones for new functions

• energy used in synthesis reactions

• used to break down smaller molecules from bigger ones (digestion)

What do animals use respiration for?

to make muscles contract

What do mammals and birds use respiration for?

to maintain a constant internal body temperature.

What do plants use respiration for?

• to move mineral ions from the soil into root hair cells

• convert nutrients into amino acids (which can then be built up into other protiens).

What changes occur during exercise?

• Heart rate increases, arteries supplying blood to muscles dilate. (increases oxygenated blood/increased rate of co_{2 removal}

• breathing rate increases and breaths deepen (rate at which oxygen is picked up by red blood cells increases)

• glycogen is converted back to glucose (provide cells with more energy)

What is the end product of anerobic respiration in animal cells?

glucose → lactic acid

Why is less energy produced in anaerobic respiration?

oxidation is incomplete

What is oxygen debt?

amount of oxygen needed to convert the lactic acid into glucose.

What is the formula for the oxygen debt repayment?

lactic acid + oxygen → carbon dioxide + water

what is the equation for anaerobic respiration in plants and yeast?

glucose → ethanol + carbon dioxide

what is fermentation?

anaerobic respiration in yeast cells. important in bread and alcoholic drinks.

what is metabolism?

The sum of all the reactions in the body

what are the liver’s metabollic functions?

• detoxifying poisonous substances

• passing the breakdown products to blood (to then be passed by urine)

• breaking down old, worn out blood cells & storing the iron

how is lactic acid removed?

blood flowing through the muscle transports the lactic acid into the liver, where it is converted back into glucose. oxygen debt is repaid once converted back into glucose and broken down in aerobic respiration. if uneeded, converted back into glycogen to be stored.

what are four examples of metabollic reactions

• conversion of glucose to starch, glycogen and cellulose

• respiration

• breakdown of excess proteins to form urea for excretion

• use of glucose and nitrate ions to form amino acids which are used to synthesise proteins