Unit 2 - tbh idk

Question 1

Digestive system

Answer 1

The digestive system ingests food and breaks it down into usable nutrients before excreting solid waste products. It includes the mouth, esophagus, stomach, and intestines.

Question 2

Endocrine system

Answer 2

The endocrine system secretes chemical signals that allow body systems to respond to environmental changes and to one another . It includes hormone-producing tissues of the pineal gland and pituitary gland in the brain; the thyroid gland; the adrenal glands; the pancreas; and the ovaries, and testes.

Question 3

Nervous system

Answer 3

The nervous system allows us to perceive and respond to the world around us. This also includes our emotions and personality. The nervous system includes the brain, the brain stem, and all the nerves

Question 4

Skeletal system

Answer 4

The skeletal system works as a support structure for your body. It gives the body its shape, allows movement, makes blood cells, provides protection for organs and stores minerals.

Question 5

Respiratory system

Answer 5

he respiratory system facilitates gas exchange between cells and the environment. The structures involved include the nasal passage, the trachea, and the lungs.

Question 6

Circulatory system

Answer 6

The cardiovascular system is responsible for the transport of materials through the body. These substances include oxygen, nutrients, hormones, and waste products. The cardiovascular system includes the heart, the blood, and the blood vessels.

Question 7

Urinary system

Answer 7

The urinary system (sometimes called the renal system) extracts and excretes dissolved waste products from the blood. The main organs that function in the urinary system are the
kidneys and bladder.

Question 8

The two parts of the human nervous system are :

Answer 8

• the central nervous system (CNS) – the brain and spinal cord
• the peripheral nervous system – nerve cells that carry information to or from the CNS

Question 9

About nerve cells

Answer 9

Nerve cells are also
called neurones. They are adapted to carry electrical impulses from one place to another:
• they have a long fibre (axon)
which is insulated by a fatty
sheath
• theyhavetinybranches
(dendrons) which branch further as dendrites at each end

Question 10

What are receptors ( where are receptors found )

Answer 10

Receptors are groups of specialised cells. They detect a change in the environment (stimulus) and stimulate electrical impulses in response. Sense organs contain groups of receptors that respond to specific stimuli.

Question 11

What are effectors

Answer 11

Effectors are parts of
the body - such as muscles and glands - that produce a response to a detected stimulus.

Question 12

Examples of effectors

Answer 12

For example:
a muscle contracting to move an arm.
muscle squeezing saliva from the salivary gland.
a gland releasing a hormone into the blood.

Question 13

Name 4 different receptors and what they do

Answer 13

• Chemoreceptors detect the presence of chemicals- located in the heart
• Thermoreceptors detect changes in temperature.- are specialized nerves
• Mechanoreceptors detect mechanical forces. – mostly found in the skin
• Photoreceptors detect light during vision.- located in the eyes

Question 14

What is reflex action

Answer 14

reflex action is a way for the body to automatically and rapidly respond to a stimulus to minimise any further damage to the body.

Question 15

What are reflex arc

Answer 15

The nerve pathway followed by a reflex action is called a reflex arc.

Question 16

How does the body sense a stimuli and react accordingly ( map / path )

Answer 16

1. Receptorintheskindetectsa stimulus (the change in temperature).
2. Sensoryneuronesends impulses to relay neurone.
3. Motorneuronesends impulses to effector.
4. Effectorproducesa response (muscle contracts to move hand away).

Question 17

About the CNS

Answer 17

The central nervous
system (CNS) controls
most functions of the body and mind. It consists of two parts: the brain and the spinal cord. The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement.

Question 18

About the PNS

Answer 18

The peripheral nervous system consists of
the nerves that branch out from the brain and spinal cord. These nerves form the communication network between the CNS and the body parts.

Question 19

What do dendrites do

Answer 19

Receive signals from other cells

Question 20

Cell body function

Answer 20

Organizes and keeps cell functional

Question 21

Cell membrane

Answer 21

Protects the cell

Question 22

Axon hillock

Answer 22

Generates impulse in the neuron

Question 23

Node of ranvier

Answer 23

Allows diffusion of ions

Question 24

Schwann cell

Answer 24

Produces the myelin sheath

Question 25

Axon

Answer 25

Transfers signals to other cells and organs

Question 26

Myelin sheath

Answer 26

Increase the speed of the signal

Question 27

Axon terminal

Answer 27

Forms junctions with other cells

Question 28

What are neurotransmitters

Answer 28

A neurotransmitter is a chemical messengers that transmit a message from a nerve cell across the synapse to a target cell. The target can be another nerve cell, or a muscle cell, or a gland cell. They are chemicals made by the nerve cell specifically to transmit the message.

Question 29

Neurons

Answer 29

They are cells in the brain that transmit and receive signals to enable processes such thought.

Question 30

Synapses

Answer 30

Where two neurons meet there is a small gap called a synapse. The plasma membranes of each neuron are in very close contact and are separated by a narrow space called a synaptic cleft. An electrical impulse cannot directly cross the gap so a neurotransmitters are used.

Question 31

Signals journey ( path whetever ) 5 steps

Answer 31

An electrical nerve impulse travels along the axon of the first neuron (presynaptic neuron). 2. When the nerve impulse reaches the dendrites at the end of the axon, chemical messengers called neurotransmitters are released. 3. Thesechemicalsdiffuseacrossthe synaptic cleft. The chemicals bind with receptor molecules on the membrane of the second neuron (postsynaptic neuron). 4. The receptor molecules on the second neuron can only bind to the specific neurotransmitters released from the first neuron. 5. The binding of neurotransmitter to the receptors stimulates the second neuron to transmit an electrical impulse along its axon. The signal therefore has been carried from one neuron to the next.

Question 32

Word and Chemical equation for aerobic respiration

Answer 32

Word equation : glucose + oxygen - carbon dioxide + water + energy (ATP) C6H12O6 - 6CO2 + 6H2O

Question 33

What is the site of aerobic respiration

Answer 33

Mitochondria

Question 34

What are catabolic and anabolic reactions

Answer 34

Catabolic reactions breaks down bigger molecules into smaller ones ( releases energy ) while anabolic reactions builds bigger molecules from smaller ones ( using energy ).

Question 35

What a catalysts

Answer 35

Catalysts are substances that increase chemical reactions but are not broken down in the process and can therefore be reused. Cells have natural catalysts known as enzymes

Question 36

What does the matrix in the mitochondria do ?

Answer 36

Contains the enzymes for aerobic respiration

Question 37

How is ATP formed and why does it have to be formed ?

Answer 37

Respiration transfers chemical energy in glucose into another molecule, ATP. Glucose is a very stable molecule that does not breakdown easily to release energy - however ATP easily breaks down and so is a more suitable source of direct energy in cells

Question 38

How is glucose broken down ( 3 points )

Answer 38

In the cytoplasm of the cell glucose is broken down into three carbon compound called pyruvic acid By a process called glycolysis. No oxygen is needed for this process but very little energy is released. If there is not enough oxygen then either lactic acid ( in humans ) is formed or alcohol and carbon dioxide ( in yeast and plants). If there is enough oxygen in the cell, the pyruvic acid is completely broken down in the mitochondria resulting in carbon dioxide and water and the production of a lot of ATP

Question 39

Equation for photosynthesis

Answer 39

Carbon dioxide + water - ( in Teh presence of sunlight and chlorophyll forms ) Glucose and oxygen

Question 40

How is a leaf adapted to absorb sunlight and carbon dioxide

Answer 40

A leaf is adapted to absorb sunlight and carbon dioxide. 1. The flat surfaces of leaves provide a large surface area for light absorption 2. The palisade cells that contain the most chloroplasts are near the top of the leaf where there is more sunlight

Question 41

How is carbon dioxide taken in by plants

Answer 41

Carbon dioxide enters the plant through pores ( stoma ) in the lower surface of the leaf and circulates in air spaces before being taken in by spongy mesophyll cells

Question 42

Enzymes ( what are tehy made up of and what enzymes break up what )

Answer 42

Enzymes are made up of protein and end in ‘ase’. Protease breaks down protein and produces amino acid , carbohydrase break down carbohydrates and produces simple sugars and glucose and lipase breaks down lipids ( fats) and produces glycerol and fatty acids, Amylase breaks down starch and produces simple sugars and glucose .

Question 43

What is active site

Answer 43

The part where enzyme reactions take place is called the active site , the active site has a specific shape

Question 44

Enzyme-substrate complex

Answer 44

Raining inside and substrate combined the form an enzyme-substrate complex

Question 45

And example of product produced by enzyme reactions

Answer 45

The products of starch digestion by amylase is the sugar maltose. Maltose is in turn broken down into glucose by the enzyme maltase.

Question 46

Lock and key mechanism

Answer 46

The way that enzymes react with the substrate is called a lock and key mechanism. The enzyme is the lock which has a specific shape into it one substrate - the key - fits. Bonds are either broken or formed ones the reactants are in the active site, forming new products

Question 47

What si respiration

Answer 47

Respiration is a chemical reaction which occurs in all living cells, releasing energy from glucose.

Question 48

Anaerobic vs aerobic respiration

Answer 48

Aerobic respiration occurs with oxygen and releases more energy but more slowly. Anaerobic respiration occurs without oxygen and releases less energy ( because glucose is not completly broken down) but more quickly ( usually happens in muscle cells in humans ). Anaerobic respiration is the release of a relatively small amount of energy in cells by the breakdown of food substances in the absence of oxygen.

Question 49

Why do we need to breath a lot after strenuous exercise ? ( 2 lareg points )

Answer 49

There is a build-up of lactic acid in the muscles during vigorous exercise. The lactic acid needs to be oxidised to carbon dioxide and water later. This causes an oxygen debt - known as excess post-exercise oxygen consumption (EPOC) - that needs to be ‘repaid’ after the exercise stops. This is why we keep on breathing deeply for a few minutes after we have finished exercising.

Question 50

End products of anaerobic respiration

Answer 50

Animal cells: lactic acid Plant cells and yeast: carbon dioxide and ethanol

Question 51

Inhibitors - 3 points main

Answer 51

Inhibitors are molecules that partially fit into an enzyme’s active site but are not broken down. They inhibit the reaction. As long as they are in the active site the substrate cannot enter to be broken down, thus reducing the rate of reactio

Question 52

Denatured

Answer 52

When an enzyme’s active site loses its shape meaning it can no longer work. Denaturing is a permanent change

Question 53

4 uses of carbohydrates

Answer 53

respiratory substrates - provides energy - stores energy - Glycoproteins/ receptors - builds macromolecules