Higher Biology - Unit 2 - Metabolism and Survival

Define metabolic pathways

sequence of reactions controlled by enzymes that change one metabolite to another

Fill in the blanks: Metabolic pathways can have ________ ______ , _________ ______ , and ___________ _______

Reversible steps, irreversible steps and alternative routes

What is the result of an anabolic reaction within metabolic pathway

Anabolic reactions **build up** large molecules from small molecules and require energy (large to small)

Give an example of an anabolic reaction

Protein synthesis / protein to amino acids

Give an example of a catabolic reaction

Aerobic respiration / Food indigestion

Give an example of how metabolic pathways can be closely linked between each other.

The energy generated by aerobic respiration (catabolic) is used for protein synthesis (anabolic)

Define alternative routes

Alternative routes through a metabolic pathway can exist which bypass stages

Define the purpose of the cell membrane

It controls the flow of materials which enter and exit the cell

Explain the mitochondrion’s membrane

The mitochondrion has a double membrane (inner and outer)

What two molecules make up the membrane

Proteins and phospholipids

What is the purpose of pores embedded in the cell membrane

They allow diffusion of specific molecules across the membrane

What is the purpose of pumps embedded in the cell membrane

To transport molecules against the concentration gradient

What is the purpose of enzymes embedded in the cell membrane

To speed up the rate of biochemical reactions

Define the activation energy

Energy required to initate a reaction - Enzymes decrease it

What effect does adding enzymes to a reaction have on the activation energy needed

It lowers the activation energy

Explain an enzymes induced fit

An induced fit occurs where the active site of the enzyme is changed slightly to better fit the substrate after the substrate binds.

What are two benefits of an induced fit

The active site comes into closer contact with substrate molecules, increases the chance of the reaction taking place

Define the affinity

The tendency for a molecule to bind to an enzyme

What does a low affinity indicate

the product has less of an attraction, this indicates the enzyme and substrate have separated

Define a competitive inhibitor

Binds at the active site preventing the substraye from binding

Define a non-competitive inhibitor

Binds away from the active site so changes the shape of the active site preventing the substrate from binding

Explain the effect of a feedback inhibitor

The end product in the metabolic pathway reaches a critical condition. This slows down the reactions in the pathway

Metabolism

All chemical reactions that occur within an organism

Define metabolic rate

The quantity of energy consumed by an organism per unit of time is called its metabolic rate

Compare bird and mammal metabolic rates to reptiles, amphibians and fish

Birds and mammals have higher metabolic rates

Describe a bird and mammals circulatory system

These organisms have a complete double circulatory system

What is a complete double circulatory system

A double circulatory system is a system in which there is no mixing off oxygenated and deoxygenated blood. Blood can also be pumped at a higher pressure

Describe advantages of double circulatory systems

More advanced

Where does the citric acid cycle take place

The matrix of the mitrochondria

Describe an amphibian and reptiles circulatory system

These organisms have an incomplete double circulatory system

Why are systems described as incomplete

Because there is only one ventricle and some mixing of oxygenated and deoxygenated blood occurs

Describe a fish circulatory system

These organisms have a single circulatory system

What circulatory system is this

A complete double circulatory system

What circulatory system is this

An incomplete double circulatory system

What circulatory system is this

A single circulatory system

Define conformers

Organisms whose internal environment is dependent on their external environment.

Define regulators

Maintains their internal enviroment regardless of external enviroment

What is a conformers advantange?

Low metabolic cost - saves energy

What is a conformers disadvantage?

Restricted to a narrow ecological niche

What is a regulators advantage?

Wide range of ecological niche

What is a regulators disadvantage?

High metabolic cost

Define homeostasis

When an organism maintains a constant internal environment regardless of the external environment

What is the purpose of the hypothalamus

The temperature monitoring centre of the brain

Define thermoregulation

The process of maintaining your core internal temperature.

Describe the process of sweating

Body heat is used to evaporate water in sweat this cools the skin

Describe the process of vasodilation

Blood capillaries in the skin dilate increasing blood flow to the skin, this increases the heat loss by radiation

What are the body’s thermoregulatory responses to heat the body up

Shivering, vasoconstriction of blood vessels, increase in metabolic rate and action of hair erector muscles

Describe the process of shivering

Rapid involuntary contraction of skeletal muscles which generate heat

Describe the process of vasoconstriction

Blood capillaries in the skin constrict this decreases blood flow to the skin and decreases heat loss by regulation

Describe the process of hair erector muscles

muscles in the skin contract, hair stands up which traps an insulating layer of air between the hair and skin

What are the body’s thermoregulatory responses to cool the body down.

Sweating, Vascodilation, Decrease in metabolic rate

Describe the process of sweating

Body heat is used to evaporate water in sweat, this cools the skin

Describe the process of vasodilation

Blood capilaries in the skin dialate increasing blood flow

Describe how decreased metabolic rate cools the body

Metabolic reactions generate heat.

Define cellular respiration

A series of metabolic pathways that releases energy from food.

What is the key role of ATP in cells

To transfer energy to cellular processes which require energy

Define fermentation

In the absence of oxygen, fermentation takes place. This does not generate ATP after glycolysis

What is more efficient fermentation or aerobic respiration

Aerobic respiration is more efficient and results in more ATP being produced

What happens in fermentation in animals

Pyruvate is converted to lactate in a reversible reaction (glucose - pyruvate - lactate)

What happens in fermentation in plants

Pyruvate is converted to ethanol and CO2 in an irreversible reaction (glucose - pyruvate - ethanol + CO2)

What is osmoregulation

The control of water concentration in the blood

Define oxaloacetate

Substance that combines with the acetyl group in citric acid cycle to form citrate

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Explain the function of dehydrogenase enzymes

Enzymes which remove hydrogen from its substrate

Define homeostasis

Maintenance of a steady state in the cells of a living organism

Define aestivation

Dormancy in a response tp high temperatures or drought

Describe dormancy

Where animals in response to adverse conditions try to survive.

Describe Migration

During a period of adverse conditions the organism will avoid this by migrating

Define consequential dormancy

Dormancy that occurs in response to the onset of adverse conditions

Give an example of dormancy

Hibernation, aestivation

Define daily torpor

period of reduced activity with organisms with high metabolic rates.

Define extremophile

Organism that lives in an environment with extreme abiotic conditions

Define hibernation

Response by an animal to avoid adverse conditions by reduction of metabolic rate

Name techniques used to study long distance migration

Tagging, radio observation,capture and release, direct observation

The ability to migrate is either _______ or ______

innate or learnt behaviour

Define innate behaviour

Unlearned instinctive behaviour

Define learned behaviour

Behaviour of an individual organism not common to all members of its species and which is acquired by experience

Define predictive dormancy

Dormancy that occurs before the onset of adverse conditions

What are the three domains of life?

Bacteria, Archaea,Eukaryota

Define Lag Phase

Little to no change in number of microbites.

Define exponential phase

Growth phase of microorganisms involving a rapid geometric increase in numbers

Describe Stationary Phase

(Secondary substances made) Nutrients in culture become depleated and toxic metabolites are produced

Define death phase

Lack of nutrients are in the culture medium

Define secondary metabolite

Substance produced during stationary phase of growth of a culture of microorganisms

Define sterile

Not containing contaminating microorganisms

Define viable cell count

Number of live cells from total cell count

What is an example of a eukaryote microorganism

Algae, yeast and slime moulds

What is an example of a bacteria microorganism

E. Coil and staphylococcus aureus

What is an example of a archaea microorganism

Methanogens and thermophiles

How can sterility be controlled

steam and filters are used. This reduces competition with desired micro-organisms for nutrients and reduce risk of spoilage

How can temperature be controlled

Water jackets and a thermostat are used to monitor and control temperature, this keeps enzymes at their optimum temperature

How can oxygen levels be controlled

Air inlets and paddles are used for aeration, this allows aerobic respiration to occur

What two methods must you use to improve the strain when working with microoganisms

Mutagenesis and Recombiant DNA

What are the two types of Mutagenic agents

radiation and chemical