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Biology A Level AQA > Exchange > Flashcards

Exchange Flashcards

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1
Q

What is ingestion?

A

Taking food in

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2
Q

What is the order of organs in digestion?

A

Teeth, salivary glands, stomach, small intestine, large intestine, rectum and anus

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3
Q

What role in digestion do teeth play?

A

Mechanical: incisors cut and tear food, molars mash food to increase surface area for enzyme action

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4
Q

What role in digestion do salivary glands play?

A

Produces saliva to lubricate food to swallow and has salivary enzymes such as amylase (amylose to maltose)

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5
Q

What role in digestion does the stomach play?

A

Glands secrete HCl (correct pH for enzymes and sterilises food)

Produces pepsin (endopeptidase)

Mechanical digestion when stomach ‘churns’

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6
Q

What are parts of small intestine?

A

Duodenum (start):

Bile and pancreatic acid are added

Peristalsis occurs

Jejunum (middle)

Ileum (end):

Villi and microvilli lining ileum

Dipeptidases (dipeptides to amino acids) and disaccharidases (disaccharides to monosaccharides) are added

End of ileum monomers are absorbed across small intestine lining into blood in capillaries

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7
Q

What part in digestion do large intestines play?

A

Reabsorbs water into blood

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8
Q

What does the rectum do?

A

Stores undigested food

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9
Q

What does the anus do?

A

Egestion (removal)

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10
Q

What are endopeptidases?

A

Enzymes that break central regions of polypeptide chains

Long chains into smaller chains

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11
Q

What are exopeptidases?

A

Enzymes that break peptide bonds on the ends of polypeptide chains

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12
Q

What are dipeptidases?

A

Enzymes that break dipeptides into amino acids

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13
Q

Where is bile produced?

A

Produced in liver and stored in gall bladder

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14
Q

What does bile do?

A

Emulsifies lipids and neutralises pH

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15
Q

What is a chylomicron?

A

Vesicle to transport lipids

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16
Q

Describe lipid absorption

A

Monoglycerides and fatty acids in lumen of intestine diffuse (simple) across membrane into the epithelial cells

They then go into the smooth ER and are recombined into triglycerides

They then move into the golgi apparatus where they are converted into chylomicrons and lipoproteins and cholesterol are added

They then move out of the cell by exocytosis into lacteal (too big to be absorbed into blood)

They are then absorbed into the blood

17
Q

What is another word for chest?

A

Thorax

18
Q

What is inspiration?

A

Breathing in:

External intercostal muscles contract

Pulls ribcage up and out

Diaphragm contracts and flattens

Increases volume in thorax, therefore decreasing the pressure

External air moves down pressure gradient and into lungs

19
Q

What is expiration?

A

Breathing out:

Internal intercostal muscles contract

Pulling ribcage down and in

Diaphragm relaxes and arcs

Less volume in thorax, therefore increasing pressure

Internal air is forced out of the lungs down the pressure gradient

20
Q

What does COPD stand for?

A

Chronic obstructive pulmonary disease

21
Q

What are the risk factors that increase the probability of someone suffering from COPD?

A 
Smoking
Air pollution
Genetics
Infections
Occupation (exposure to harmful chemicals/dust)
22
Q

Define correlation

A

When a change in 1 of 2 variables is reflected in a change of the other variable

23
Q

Define causation

A

When you can claim that the one variable actually causes the other variable

24
Q

Describe the path of oxygen in humans

A

Oxygen in the air moves in down the trachea into the bronchi. It then enters the bronchioles and then alveoli, where the oxygen dissolves in the surfactant in the alveoli, allowing it to diffuse over the epithelial and endothelial cells into the blood.

25
Q

Describe the tracheal system of an insect

A

Oxygen moves into the insect through spiracles, passing through the dust filter

Tracheae are held open by rings of chitin (collapse prevention)

Tracheoles extend throughout the insect’s body tissues, carrying oxygen directly to respiring cells and removing carbon dioxide

There is a short diffusion pathway between the tracheoles and the body cells.

26
Q

What are the key points for countercurrent flow?

A

Water and blood flow in opposite directions so blood is always meeting water with a higher oxygen concentration

This means concentration/ diffusion gradient is maintained across the whole length of the gill lamella

Therefore diffusion of oxygen into the blood can occur across the whole length of the gill lamella

This ensures maximum possible gas exchange is achieved

Biology A Level AQA (14 decks)

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