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Organisations Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Cells

A

Cells are the smallest unit that can live on their own. they are the basic building blocks of all living organisms.

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2
Q

Tissue

A

A tissue is a group of cells with a similar structure and function working together.

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3
Q

Organs

A

Organs are aggregations of tissues, working together to perform specific functions.

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4
Q

Organ systems

A

A group of organs with related functions, working together to perform certain functions. Organs are organised into organ systems, which work together to form organisms.

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5
Q

Stomach

A

The stomach is an organ that forms part of the digestive system. It churns food to break it down and produces protease enzymes. It contains HCl to destroy bacteria and provide an optimum pH for the protease enzymes.
Epithelial tissue lines the stomach, muscle tissue contains cells to contract and glandular tissues that contain cells which secrete enzymes and stomach acid.

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6
Q

Digestion

A

The digestive system is an example of an organ system in which several organs work together to digest and absorb food.
Digestion is the process in which large, insoluble molecules are broken down into smaller, soluble molecules so they can be absorbed into the bloodstream.

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7
Q

Alimentary canal

A

The human digestive system is made up of organs that form the alimentary canal. The alimentary canal is the channel or passage through which food flows through the body, starting at the mouth and ending at the anus.

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8
Q

Mouth / salivary glands

A

The mouth is where mechanical digestion takes place. teeth chew food to break it into smaller pieces to increase surface area to volume ratio. amylase enzymes in saliva start digesting starch into maltose. The food is shaped into a bolus by the tongue and lubricated in saliva so it can be swallowed easily.

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9
Q

Oesophagus

A

Tube that connects the mouth to the stomach where the food goes after being swallowed. contractions will take place in order to push the food molecules down.

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10
Q

Small intestine

A

First section is called the duodenum and is where the food from the stomach finishes being digested by enzymes produced here and secreted from the pancreas. Ph of the small intestine is slightly alkaline PH 9-8.
second section is called the ileum and is where absorption of digested food molecules takes place. the ileum is long and lined with villi to increase the surface area over which absorption can take place.

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11
Q

Large intestine

A

Water is absorbed from remaining material in the colon to produce faeces which is stored in the rectum and excreted through the anus

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12
Q

Pancreas

A

Produces all three types of digestive enzymes (protease, amylase and lipase)
Secretes enzymes in an alkaline fluid into the duodenum to raise the PH of the fluid coming out of the stomach.

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13
Q

Liver

A

Produces bile to emulsify fats (break down of larger droplets into smaller droplets) - an example of mechanical digestion.

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14
Q

Gall bladder

A

Stores bile to release into duodenum as required.

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15
Q

Bile

A

Bile is an alkaline substance produced in the liver and stored in the gallbladder. Enzymes in the small intestine operate best in alkaline conditions.
Bile neutralises acid from the stomach to stop these enzymes becoming denatured (lose their activity).
Bile breaks up fats into tiny droplets, through a process called emulsification.
The tiny droplets have a higher surface area than the original fat drop.
This increases the rate of the lipase-catalysed reactions that break fats down.

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16
Q

Enzymes

A

Enzymes are a biological catalyst – they help speed up reaction rates in an organism. Enzymes are proteins that have a shape that is specific to the substrates they work on. The part of an enzyme that the substrate fits into is called an active site. When a substrate collides with its specific enzymes’ active site, the two molecules temporarily bind. Here, the bonds holding the substrate together break and the resultant products leave the active site. The enzyme remains unchanged and can catalyse the breakdown of another specific substrate molecule.

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17
Q

Effect of temperature on enzymes

A

As temperature increase (towards the optimum), kinetic energy increases. This means that the substate in the enzyme are more likely to collide - there will be more frequent successful collisions This increases the rate of reaction. Optimum temperature is when the rate of reaction is the quickest - usually body temperature. Above the optimum temperature, the shape of the active site is altered as the bonds holding it in the right shape are broken. The enzyme is denatured. The Substrate can no longer fit into the active site, so the rate of reaction falls until it reaches 0.

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18
Q

Effect of PH on enzymes

A

Like with temperature, enzymes have an optimum PH. This is the PH at which the rate of reaction is quickest. If the PH becomes more acidic or more alkaline than the optimum, the rate of reaction will decrease. This is because the incorrect PH will denature the enzyme - It will change the shape of the active site. So, the enzyme and the substrate can no longer bind.

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19
Q

Production of enzymes

A

Protease are produced in the stomach, pancreas and small intestine
Carbohydrase are produced in the salivary glands and pancreas
Lipase are produced in the stomach, pancreas and the mouth

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20
Q

Carbohydrase

A

Carbohydrases break down carbohydrates to simple sugars.
Amylase is a carbohydrase which breaks down starch into maltose, which is then broken down into glucose by the enzyme maltase.
Amylase is made in the salivary glands, the pancreas and the small intestine.

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21
Q

Protease

A

Proteases are a group of enzymes that break down proteins into amino acids in the stomach and small intestine.
Protein digestion takes place in the stomach and small intestine, with proteases made in the stomach (pepsin), pancreas and small intestine.

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22
Q

Lipase

A

Lipases break down lipids (fats) to glycerol and fatty acids.
Lipase enzymes are produced in the pancreas and secreted into the duodenum.

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23
Q

Products of digestion

A

The products of digestion are used to build new carbohydrates, lipids and proteins required by all cells to function properly and grow.
Some glucose released from carbohydrate breakdown is used in respiration to release energy to fuel all the activities of the cell.
Amino acids are used to build proteins like enzymes and antibodies.
The products of lipid digestion can be used to build new cell membranes and hormones.

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24
Q

Test for starch

A

Iodine reagent
Positive result = orange to blue / black

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25
Q

Test for protein

A

Biuret reagent
Positive result = blue to light purple

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26
Q

Test for glucose

A

Benedict’s reagent
Hot water bath (70 – 80 degrees)
Positive result = blue to brick red precipitate

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27
Q

Test for lipids

A

Ethanol reagent
Add cold water to the solution
Positive result = colourless to cloudy

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28
Q

Adaptations for gas exchange

A

All gas exchange surfaces have features to increase the efficiency of gas exchange including:
Large surface area to allow faster diffusion of gases across the surface.
Thin walls to ensure diffusion distances remain short.
Good ventilation with air so that diffusion gradients can be maintained.
Good blood supply (dense capillary network) to maintain a high
concentration gradient so diffusion occurs faster.

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29
Q

Ribs

A

Ribs are a bone structure that surround and protect the lungs, they also aid breathing moving up and out or down and in.

30
Q

Intercostal muscles

A

Muscle between the ribs which control movement, causing inhalation and exhalation.

31
Q

Diaphragm

A

Sheet of connective tissue and muscle at the bottom of the thorax that helps that helps to change the volume of the thorax to allow inhalation and exhalation.

32
Q

Trachea

A

Windpipe that connects the mouth and the nose to the lungs, lined with goblet cells to produce mucus and ciliated epithelial cells which move the mucus up and down.

33
Q

Bronchus

A

Large tubes branching of the trachea with one bronchus for each lung, also lined with goblet cells and ciliated epithelial cells.

34
Q

Bronchioles

A

The bronchi split to form smaller tubes called bronchioles in the lungs connected to alveoli.

35
Q

Alveoli

A

Tiny moist air sacs where gas exchange takes place, each alveoli is covered in capillaries.

36
Q

Arteries

A

Arteries transport blood from the heart to the organs. They transport blood away from the heart.
Artery walls have thick layers of muscle. This makes them strong and able to cope with the high pressure at which blood is pumped out by the heart.
The walls have elastic fibres, allowing them to stretch and spring back (recoil).

37
Q

Capillaries

A

Arteries branch into much smaller vessels, called capillaries. Capillaries have thin walls and pass very close to the body cells. Capillaries are the smallest blood vessel at around 7-10um (micrometres) in diameter. This means that red blood cells must pass through the capillaries 1 at a time. They are also 1 cell thick which means oxygen can diffuse into the system faster. Their function is gas exchange.

38
Q

Veins

A

Veins form when capillaries join up after passing through the body. They transport blood back to the heart.
The walls are thinner than those found in the arteries as the blood is at a lower pressure.
Low pressure hinders blood flow. This means that veins have a wider cross-section through which blood can flow to counteract this.
Veins have valves to prevent the backflow of blood.

39
Q

heart

A

The heart is made of muscle. The heart muscle continually contracts and relaxes. It uses a lot of energy. The heart muscle receives oxygen and glucose for respiration from the blood brought by the coronary artery.

The heart has two pumps (a double circulation) that beat together about 70 times every minute of every day. a double circulatory system is one in which blood flows through the heart twice and is pumped twice, once through the lungs and again around the body.

Each pump has an upper chamber (atrium) that receives blood and a lower chamber (ventricle) that pumps out blood. Both atria fill and pump blood out at the same time, as do both ventricles. The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker. there are two ventricles so that oxygenated and deoxygenated blood don’t mix.

40
Q

Blood flow around the body

A

Blood from the body contains very little oxygen and is transported to the right atrium via the veena cava. The blood passes through the tricuspid valve into the right ventricle. Blood is then pumped from the right ventricle to the lungs via the pulmonary artery to become oxygenated. Oxygenated blood from the lungs enters the heart at the left atrium via the pulmonary vein. It then passes through the bicuspid valve and enters the left ventricle where it is then pumped to the rest of the body via the aorta.

41
Q

Blood

A

Blood is a tissue made up of plasma, red blood cells, white blood cells and platelets.

42
Q

Platelets

A

Platelets clot the blood, fragment of cells that can link together in meshes to stop escape of blood.
Less than 1% of the blood is made up of plasma.

43
Q

Red blood cells

A

Function – transports oxygen (and carbon dioxide round the body)

No nucleus (creating a biconcave shape) to create more space for oxygen
Contains haemoglobin which binds to oxygen
Large surface area to maximise oxygen uptake
They travel through capillaries. Red blood cells are larger than the diameter of the capillary maximising contact between the red blood cells and the capillary. Therefore, lots of oxygen is dropped of at the cell.
Once oxygen has been dropped off it picks up carbon dioxide and transports it back to the lungs
45% of the blood is made up of RBC

44
Q

White blood cells

A

Function - destroy pathogens

Can change shape to exit blood vessels and chase pathogens.
Large nucleus provides an immunological memory.
Lysosomes containing enzymes to digest engulfed pathogens.
less than 1% of the blood is made up of WBC

45
Q

Plasma

A

Function - to transport solutes (things that can dissolve in the blood) like glucose, minerals and amino acids
Has proteins in it that can help control the PH.
55% of the blood is plasma.

46
Q

coronary heart disease

A

Coronary heart disease is caused when fatty material is deposited inside the coronary arteries.
Blood flow is reduced and less glucose and oxygen reach the heart for respiration.
This means that less aerobic respiration and more anaerobic respiration takes place so less energy is released.
Less energy is available for the heart to contract so less glucose and oxygen are transported to the working muscles by the blood from the heart.
Less carbon dioxide is removed from the body resulting in breathlessness and tiredness.
If cells are starved of nutrients, they can die and a heart attack can happen.
Factors that can contribute to coronary heart include: Genetic factors, Gender, Age, Diet And smoking status.

47
Q

heart failure

A

when the heart fails to pump blood effectively.
Causes: valves leaking, causing backflow and weakness in heart muscles (usually due to old age).

When heart failure occurs, the only effective treatment is a donor heart transplant. An artificial heart can be used in the short term, while the patient is waiting for a heart transplant, or allow the heart to rest to help recovery.

48
Q

statins

A

High cholesterol levels are treated with drugs called statins which stop the liver producing as much cholesterol. Patients can also change their diet to help reduce cholesterol.

Disadvantages - need to be taken regularly and long term otherwise they are not as effective.
Takes time to have an effect.
Side effects include muscle and joint pain and kidney problems.

49
Q

stents

A

Stents are used to treat narrow coronary arteries by widening the lumen to increase blood flow. If the coronary artery is too damaged, bypass surgery is used. A vein is transplanted from the leg to bypass the blockage.

Disadvantages - Risk of blood clots occurring.
Risk of infection during surgery.
Risk of damage to blood vessels during surgery.

50
Q

heart valves

A

Heart valves prevent the backflow of blood.
They can become faulty due to heart attack, infection or old age.
Faulty valves may not open fully or can leak, causing oxygenated and deoxygenated blood to mix. Symptoms include: tiredness, lack of energy and breathlessness.
Faulty heart valves can be replaced using biological (from humans or other mammals) or mechanical valves.

51
Q

Risk factors

A

Risk factors are factors that increase the probability of developing a disease. Often, non-communicable diseases arise due to the interaction (acting together) of numerous risk factors. Risk factors can be placed into one of two categories:
Lifestyle
For example, an unbalanced diet or not enough exercise.
Substances can be in both the individual’s body or the environment.
For example, the chemicals inhaled when smoking.

52
Q

Risk factors (smoking)

A

Poor diet, smoking and lack of exercise are proven risk factors for cardiovascular disease.
Smoking is a proven risk factor for lung diseases.
Smoking during pregnancy is a proven risk factor for the low birth weight of babies.
Excessive alcohol consumption during pregnancy is a proven risk factor for brain damage in babies.
Chemical carcinogens and exposure to ionising radiation (radiation that can damage cells) is a proven risk factor for cancer.

53
Q

Risk factor (diet)

A

Poor diet, smoking and lack of exercise are proven risk factors for cardiovascular disease.
Obesity is a proven risk factor for Type 2 diabetes.

54
Q

Risk factors (alcohol)

A

Excessive alcohol intake is a risk factor for liver and brain damage.
Cirrhosis of the liver.

55
Q

Cancer

A

Cancer is the result of changes in cells that lead to uncontrolled growth and division.

Benign tumours are growths of abnormal cells which are contained in one area, usually within a membrane. They do not invade other parts of the body.

Malignant tumour cells are cancers. They invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours.

Scientists have identified lifestyle risk factors for various types of cancer. There are also genetic risk factors for some cancers.

56
Q

Upper epidermis

A

Protective barrier against damage and pathogens.
Translucent so it can let light go through to the palisade mesophyll.

57
Q

Spongy mesophyll

A

Less highly packed irregular shaped cells
Contains less than 20% of the chloroplast
Air spaces for gas exchange

58
Q

Palisade mesophyll

A

Regular box-like structure to maximise photosynthesis
Contains over 80% of the chloroplast

59
Q

Vascular bundle

A

Contains xylem cells for transport of water and mineral ions
Contain phloem cells for transport of amino acids and dissolved sugars (sucrose)

60
Q

Waxy cuticle

A

It is waterproof to stop water evaporating out of the leaf

61
Q

Xylem

A

Function – transport tissue for water and mineral ions

Xylem cells line up in tubes and the individual cell walls break down to make xylem vessels which are long and hollow
Cells are dead (have no organelles or cytoplasm) – less resistance for easier flow of water
Xylem outer walls contain lignin – lignin strengthens the vessel, providing support to the plant

62
Q

Phloem

A

Function – transport of dissolved sugars and amino acids

Surrounded by companion cells which are found along the outside of the phloem vessels
Contain many mitochondria to provide energy for translocation
The energy released by companion cells are used to help transport the sugars and amino acids (translocation)
Cells have limited amount of cytoplasm and no vacuole to reduce the resistance of flow
Phloem cells are joined end – to – end to make a tube/vessel
They are 2-way which allows substances to be transported all around the phloem
Contain sieve plates – the cell walls between adjacent phloem cells have pores in them to allow material through. The modified cells wall with the pores are known as sieve plates

63
Q

Palisade cells

A

Function – carry out photosynthesis in the leaves

Regular shape to pack tightly together. Lots of palisade cells can fit into one layer at the top of the leaf too maximise photosynthesis
Contains many chloroplasts containing chlorophyll
Most chloroplasts are found near the top of the cell where there is the most light

64
Q

Guard cells

A

Function – open and close the stomata to allow gas exchange in plants

Banana – shaped cells that are found in pairs
They contain chloroplasts so they can do some photosynthesis
They change shape to open and close the stomata (gap between the guard cell) to allow gas exchange in the leaves

65
Q

Root hair cell

A

Function – absorption of water and mineral ions from soil

Has a projection to increase surface area so the rate of water uptake is greater
Thinner walls than other plant cells so that the water can move through easily (due to shorter diffusion distance)
Mitochondria for active transport of mineral ions
No chloroplast – there’s no light for photosynthesis underground

66
Q

Artificial heart advantages and disadvantages

A

Advantages - short waiting times
Less chance of patients immune system rejecting it.

Disadvantages - Do not work as well as real hearts.
Increased risk of blood clot, leading to increased risk of stroke.

67
Q

Transpiration stream

A

The flow of water through a plant, from the roots to the leaves, via the xylem vessels. Water will eventually be lost by evaporation out of the stomata.

68
Q

Transpiration

A

The loss of water from leaves by evaporation through the stomata.

69
Q

Limiting factors of transpiration

A

Increasing the light intensity, increases photosynthesis and plants need more CO2. The stomata open to let the gas in but this leads to water loss by transpiration.

Increasing the temperature, increases the kinetic energy of the water molecules in the leaf and this leads to loss of water by evaporation (transpiration)

Increasing the windspeed carries the water molecules away from the leaf faster and this leads to a high concentration as there is more water in the leaf than outside so more water leaves through transpiration.

Increasing the humidity means that there is lots of water in the air and lots of water in the leaf this means it is close to an equilibrium so a lower concentration gradient, so it slows down the rate of transpiration.

70
Q

Translocation

A

The movement of amino acids and dissolved sugars around the plant mainly from the leaves to the roots.

71
Q

Inhaling

A

When we inhale, the intercostal muscles between the ribs contract, this moves the ribs up and out, the diaphragm muscle contracts and moves down and the volume of air inside the chest increases. This decreases the pressure inside the chest and the air pressure outside the chest is higher so air enters the lungs.

72
Q

Exhaling

A

When we exhale, the intercostal muscles between the ribs relax, this moves the ribs down and in , the diaphragm muscle relaxes and moves up and the volume of air inside the chest decreases. This increases the pressure inside the chest and the air pressure outside the chest is now lower so air leaves the lungs.

Biology (8 decks)

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