Biology Study Notes:
PP1: Coordinated body systems, metabolism & getting nutrients
Metabolism:
- The chemical process that maintain life and allow organisms to grown and reproduce,
maintain their structures and respond to their environment.
- 2 groups;
- Reactions that break down organic matter: respiration breaks down glucose molecules to
release energy.
- Reactions that build complex molecules from simpler substances: making new cells requires
complex molecules like proteins and nucleic acids to be made from smaller molecules.
Enzymes:
- Organic catalysts that speed up the rate of a chemical reaction without being used or
changed in the reaction
- Enzymes only catalyse one particular chemical reaction
- They are proteins
- Each enzyme has a particular shape that allows itself to attach to a specific substrate (the
molecule/ reactant), the substrate is going to be modified or changed during the chemical
reaction.
Lock and Key Model: The active site on the enzyme has a specific shape (like a lock) and only one
substrate, can fit exactly into the active site (like a key).
Induced fit Model: The active site must change slightly when it interacts with the substrate so that
they fit together perfectly.
Getting Nutrients:
- The food you eat contains molecules that are broken down by enzymes in the digestive
system, into smaller molecules that can pass through the walls of the intestine into the
bloodstream.
- Carbohydrates are broken down into glucose.
- Proteins are broken down into amino acids.
- Lipids (fats and oils) are broken down into fatty acids and glycerol.
- These small molecules are then small enough to pass through the thin walls of the villi into
the small intestine, then into the capillaries and then into the bloodstream.
Diffusion:
- The movement of particles in a substance from an area of high concentration to an area of
low concentration.
- Takes place in liquids and gases where the particles have enough energy to move around
freely.
- Diffusion of oxygen in the lungs: From the alveoli, the oxygen from the air you breathe
enters your blood in nearby blood vessels. The oxygen in your blood is then carried around
the body in the bloodstream, reaching every cell. When the oxygen passes into the blood
stream, the carbon dioxide leaves it.
,Diffusion in action: Oxygen is in higher concentration in the alveoli than in the blood; therefore, it
moves by diffusion from the alveoli space into the capillaries in the lungs. In the blood oxygen
attaches to haemoglobin in red blood cells. The flow of blood carries the oxygen away, so the
concentration in the blood and alveoli don’t become equal, so oxygen is continually taken into the
blood.
Pathway of air into your lungs: Breathing in - Trachea – Bronchi – Bronchioles – Alveoli – Lungs –
Capillaries – Bloodstream (via diffusion).
Capillaries: Are tiny vessels that branch out to form networks around body cells. In the lungs
capillaries absorb oxygen from inhaled air into the bloodstream and release carbon dioxide for
exhalation.
Alveoli: Tiny air sacs in your lungs that exchange oxygen and carbon dioxide molecules to and from
the blood stream. When you breathe in oxygen the oxygen passes through the alveoli and into the
blood and travels to the tissues throughout the body.
Mitochondria:
- The powerhouse of the cell.
- Oxygen and glucose enter a cell from the bloodstream and are used in the mitochondria in a
process called cellular respiration.
- Cellular respiration is a series of chemical reactions controlled by enzymes, that release
chemical energy from the breakdown of glucose.
Liver:
- Removes and modifies wastes from your body
- Breaks down; hormones, haemoglobin from dead red blood cells, medicines and alcohol
(toxic substances).
Lysosomes: Contain waste products and break down larger molecules into smaller ones that move
into the bloodstream for removal by the kidneys.
, PP2: Nervous control and nerves
The nervous system is made up of 2 main parts; Central Nervous System (CNS) and the Peripheral
Nervous System (PNS)
Central Nervous System (CNS):
- Made up of the brain and spinal cord.
- Receives information from the whole body, processes the information and then sends
messages back to the body telling the body how to respond.
- The spinal cord carries messages (signals) back and forth between the brain and the PNS
Peripheral Nervous System (PNS):
- Made up of nerves that carry messages to and from the CNS and other parts of your body
- Made up of sensory receptors and nerves
- Two parts; Somatic and Autonomic nervous systems
Somatic Nervous System (PNS):
- Connects the central nervous system to the body's muscles to control voluntary movements
and reflex arcs.
- Contains two major types of neurons; sensory neurons (Takes sensory info and takes it to
the brain and spinal cord.) and motor neurons (Carry messages from the CNS to effectors).
Autonomic Nervous System (PNS):
- Regulates involuntary bodily functions; blood flow, heartbeat, digestion, breathing.
- Two parts; Sympathetic system (fight or flight response), parasympathetic system (maintains
normal bodily functions).
Neurons:
- Specialised cells that electrical messages from one part of the body to another at high
speeds. The electrical impulses are nerve impulses and they can only travel in one direction.
- Cell body; contains the nucleus
- Dendrites; receive messages from other nerve cells and send off electrical signals
- Axon; sends nerve impulses in one direction
- Axon terminal; passes the message onto the next neuron
- Myelin Sheath; the layer of insulation surrounding nerves
PP1: Coordinated body systems, metabolism & getting nutrients
Metabolism:
- The chemical process that maintain life and allow organisms to grown and reproduce,
maintain their structures and respond to their environment.
- 2 groups;
- Reactions that break down organic matter: respiration breaks down glucose molecules to
release energy.
- Reactions that build complex molecules from simpler substances: making new cells requires
complex molecules like proteins and nucleic acids to be made from smaller molecules.
Enzymes:
- Organic catalysts that speed up the rate of a chemical reaction without being used or
changed in the reaction
- Enzymes only catalyse one particular chemical reaction
- They are proteins
- Each enzyme has a particular shape that allows itself to attach to a specific substrate (the
molecule/ reactant), the substrate is going to be modified or changed during the chemical
reaction.
Lock and Key Model: The active site on the enzyme has a specific shape (like a lock) and only one
substrate, can fit exactly into the active site (like a key).
Induced fit Model: The active site must change slightly when it interacts with the substrate so that
they fit together perfectly.
Getting Nutrients:
- The food you eat contains molecules that are broken down by enzymes in the digestive
system, into smaller molecules that can pass through the walls of the intestine into the
bloodstream.
- Carbohydrates are broken down into glucose.
- Proteins are broken down into amino acids.
- Lipids (fats and oils) are broken down into fatty acids and glycerol.
- These small molecules are then small enough to pass through the thin walls of the villi into
the small intestine, then into the capillaries and then into the bloodstream.
Diffusion:
- The movement of particles in a substance from an area of high concentration to an area of
low concentration.
- Takes place in liquids and gases where the particles have enough energy to move around
freely.
- Diffusion of oxygen in the lungs: From the alveoli, the oxygen from the air you breathe
enters your blood in nearby blood vessels. The oxygen in your blood is then carried around
the body in the bloodstream, reaching every cell. When the oxygen passes into the blood
stream, the carbon dioxide leaves it.
,Diffusion in action: Oxygen is in higher concentration in the alveoli than in the blood; therefore, it
moves by diffusion from the alveoli space into the capillaries in the lungs. In the blood oxygen
attaches to haemoglobin in red blood cells. The flow of blood carries the oxygen away, so the
concentration in the blood and alveoli don’t become equal, so oxygen is continually taken into the
blood.
Pathway of air into your lungs: Breathing in - Trachea – Bronchi – Bronchioles – Alveoli – Lungs –
Capillaries – Bloodstream (via diffusion).
Capillaries: Are tiny vessels that branch out to form networks around body cells. In the lungs
capillaries absorb oxygen from inhaled air into the bloodstream and release carbon dioxide for
exhalation.
Alveoli: Tiny air sacs in your lungs that exchange oxygen and carbon dioxide molecules to and from
the blood stream. When you breathe in oxygen the oxygen passes through the alveoli and into the
blood and travels to the tissues throughout the body.
Mitochondria:
- The powerhouse of the cell.
- Oxygen and glucose enter a cell from the bloodstream and are used in the mitochondria in a
process called cellular respiration.
- Cellular respiration is a series of chemical reactions controlled by enzymes, that release
chemical energy from the breakdown of glucose.
Liver:
- Removes and modifies wastes from your body
- Breaks down; hormones, haemoglobin from dead red blood cells, medicines and alcohol
(toxic substances).
Lysosomes: Contain waste products and break down larger molecules into smaller ones that move
into the bloodstream for removal by the kidneys.
, PP2: Nervous control and nerves
The nervous system is made up of 2 main parts; Central Nervous System (CNS) and the Peripheral
Nervous System (PNS)
Central Nervous System (CNS):
- Made up of the brain and spinal cord.
- Receives information from the whole body, processes the information and then sends
messages back to the body telling the body how to respond.
- The spinal cord carries messages (signals) back and forth between the brain and the PNS
Peripheral Nervous System (PNS):
- Made up of nerves that carry messages to and from the CNS and other parts of your body
- Made up of sensory receptors and nerves
- Two parts; Somatic and Autonomic nervous systems
Somatic Nervous System (PNS):
- Connects the central nervous system to the body's muscles to control voluntary movements
and reflex arcs.
- Contains two major types of neurons; sensory neurons (Takes sensory info and takes it to
the brain and spinal cord.) and motor neurons (Carry messages from the CNS to effectors).
Autonomic Nervous System (PNS):
- Regulates involuntary bodily functions; blood flow, heartbeat, digestion, breathing.
- Two parts; Sympathetic system (fight or flight response), parasympathetic system (maintains
normal bodily functions).
Neurons:
- Specialised cells that electrical messages from one part of the body to another at high
speeds. The electrical impulses are nerve impulses and they can only travel in one direction.
- Cell body; contains the nucleus
- Dendrites; receive messages from other nerve cells and send off electrical signals
- Axon; sends nerve impulses in one direction
- Axon terminal; passes the message onto the next neuron
- Myelin Sheath; the layer of insulation surrounding nerves
