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Biology🧬 > Exchange > Flashcards

Exchange Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

How would you work out the Surface Area : Volume ratio?

A
  1. Work out surface area: length x width x number of sides
  2. Work out volume: length x width x height
  3. Do surface area divided by volume
  4. Ans:1
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2
Q

What type of SA:V ratio do large and small animals have?

A

Small: have a high ratio, e.g a mouse is 6:1

Large: have a low ratio, e.g hippo is 2:1

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3
Q

How are single-celled organisms different to multicellular organisms withy SA:V ratio?

A

In a singular celled organism substances can diffuse directly in and out of the cell- it is quick because of the short diffusion pathway.

However, in multicellular organisms diffusion would be too slow as we have cells deep within our body so a large distance and a low SA:V ratio, so we need exchange organs and mass transport systems.

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4
Q

How might it be better for animals to adapt to aid exchange?

A

Size: if an animal is larger it has a lower SA:V ratio, so it is harder to lose heat, opposite for smaller animals, so they have to have a high metabolic rate to generate enough heat.

Shape: animals with a compact shape (e.g round head) have low SA:V, minimising heat loss, whereas more sticky out features with a large SA:V increase heat loss.

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5
Q

Why can’t insects take in water and gases through their exoskeleton?

A

The exoskeleton (chitin) is impermeable to water, oxygen , and carbon dioxide, for gas exchange occurs through pores in the body surface.

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6
Q

What is the structure of an insects gas exchange system?

A

-Has pore openings in the body surface called spiracles.
-Tubes called tracheae and tracheoles extend the spiracles into the body’s tissues.
-Rings of chitin prevent collapse when the air pressure inside the tracheae is less than atmospheric pressure.

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7
Q

How has the insects gas exchange system adapted to reduce water loss and gain sufficient oxygen?

A

-Spiracles have valves that open and close to prevent water loss.
-Spiracles have tiny hairs for dust filters.
-Lots of tracheoles that are one cell thick for a short diffusion distance.
-High surface area

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8
Q

How does an insects tracheal system work?

A
  • A solution of gases and other substances fill the ends of the tracheoles.
  • Oxygen and carbon dioxide are exchanged between the solution filling the ends of the tracheoles and cells of tissues nearby.
  • Oxygen is supplied to tissues, CO2 is removed. (going down their conc gradients)

They use Rhythmic abdominal movements to move air in and out of the spiracles.

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9
Q

What type of circulatory system do fish have?

A

Single circulatory system where blood flows through the heart once for each circuit of the body.

Heart > Gills > Body > Heart

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10
Q

Describe the structure of gas exchange in a fish

A
  • Bone called a gill arch
  • Filament project from the Gill arch
  • Lamellae are folds on the filaments
  • Operculum is a flap which cover the gill slits
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11
Q

What is the benefit of a countercurrent in a bony fish?

A

The water and their blood flows in opposite directions.

This means that a concentration gradient of oxygen from the water into the bloodstream can always be maintained, as it diffuses from high to low, along the length of the filament.

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12
Q

What are the adaptations of that gas exchange system in a bony fish?

A
  • Filaments provide a large surface area
  • Lamellae provide an even bigger surface area as they are folded
  • Countercurrent maintains conc gradient, maximising diffusion
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13
Q

What is the respiratory current (fish)?

A

The flow of water through the mouth and over the lamellae- there is a continuous flow of water over the lamellae.

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14
Q

What is ‘Inspiration’ (fish)?

A

-Lowering the floor of the pharynx (mouth, bottom lip) increases the vol of the mouth cavity and reduces pressure.
-Water flows in through the open mouth and over the lamellae.

(ventilation)

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15
Q

What is ‘Expiration’ (fish)?

A

-Raising the floor of the pharynx (mouth, top lip) reduces the volume of the mouth cavity and increases pressure.
-The pressure pump effect pushes water over the lamellae and against the opercula, pressing them open.
-So water is able to leave the fish.

(ventilation)

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16
Q

Name everything in the cross section of a leaf, and their function

A

Waxy cuticle: prevents evapouration of water

Upper/lower epidermis: prevents pathogens getting in, transparent

Palisade mesophyll: contains tightly packed chloroplasts for photosynthesis

Spongy Mesophyll: air spaces for gas exchange/circulation

Vascular bundle: contains xylem and phloem for transpiration and translocation

Stomata: pores for gas exchange and transpiration

Guard cells: open and close for gas exchange

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17
Q

What are some factors effecting gas exchange in plants?

A

-Increased temp
-Decrease humidity
-Increase wind
-Increase light intensity

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18
Q

What is the ‘Compensation Point’ in a leaf?

A

when the conc of CO2 produced in aerobic respiration balances that used in photosynthesis, then the net exchange of CO2 between the leaf and the atmosphere is zero.

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19
Q

What does Xerophytic mean?

A

Plants that are able to survive in hot, dry conditions.

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20
Q

How does stomata open and close?

A
  • Guard cells fill with water and become turgid, and push apart. this is because there active transport of K+ ions into the cells from surrounding cells, so the guard cells now have water potential of guard cells becomes negative, water passes in via osmosis.
  • Active transport of K+ ions is activated by light and photosynthesis, therefore the whole of the above process is reversed, stomata closes.
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21
Q

Name the features of the human gas exchange system and their function

A

Nasal cavity: is moist to dissolve gas, has hairs to trap microorganisms, warms up the air

> Pharynx and larynx

Trachea: Route to lungs, has ‘C’ rings of cartilage for support and flexibility.

Bronchus: same as trachea but smaller.

Bronchioles: has a layer of muscle that can contract and relax to control air flow.

Alveoli: One cell thick , flattened epithelial cells, good blood supply as wrapped in capillaries, lined with collagen and elastic fibres so the don’t break under air pressure.

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22
Q

What happens to our body during inhalation?

A

-Diaphragm contracts and flattens, increasing volume
-External intercostal muscles contact, internal relax
-Therefore the ribcage moves up and out
-Volume of the thorax (chest) increases, pressure decreases
-Air is drawn in

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23
Q

What happens to our body during exhalation?

A

-Diaphragm relaxes and becomes dome shaped
-External intercostal muscles relax, internal contract
-Ribcage moves down and in
-Volume of thorax (chest) decreases, pressure increases
-Air is forced out

24
Q

Talk about the atmospheric pressure in terms of inhalation and exhalation

A

Inhalation: want the atmospheric pressure to be lower inside the lungs and higher outside so that air can move from a high to low conc (into the lungs)

Exhalation: Atmospheric pressure to be higher inside than outside the lungs, for a conc gradient, loss of air.

25
Q

What is the pleural cavity and what is its function?

A

The space between the lungs and the ribcage. Lubricated membranes for easier movement of the lungs.

26
Q

How do insects reduce water loss?

A

-Small surface areas to volume ratio
-Exoskeleton is impermeable
-Control opening and closing of spiracles (CO2 conc)

27
Q

Why do larger organisms need specialised gas exchange systems?

A

The diffusion distance is too large from the surface to cells, so specialised gas exchange surfaces with an increased surface area reduce the distance.

28
Q

How could you find out where and how many stomata there are on a plant leaf? (bit of a weird one)

A

-Use clear nail varnish to coat the underside of the leaf, leave to dry and peel away.
-Place under a light microscope and count the presence of guard cells

29
Q

Apart from gases, what other dissolved substances are exchanged in fish?

A

Ions and the regulation of pH is managed by the gills.

30
Q

What are the adaptations of a dicotyledonous leaf for diffusion?

A

-Thin leaves
-Air spaces, increases Sa:V
- Stomata

31
Q

What is Carbohydrase?

A

An enzyme that catalyses the digestion of carbohydrates such as starch into simple sugars.

32
Q

What is Protease?

A

An enzyme that catalyses the digestion of protein into amino acids.

33
Q

What is Lipase?

A

An enzyme that catalyses the digestion of triglycerides into fatty acids and glycerol.
-Breaks ester bonds
-Made in the pancreas, released into the small intestine.

34
Q

Where can carbohydrases be found and how do they work?

A

-Saliva in the mouth contains amylase, catalysing the hydrolysis of starch into maltase (chloride ions activate the amylase).

-The duodenum receives pancreatic juice from the pancreas that also contains amylase.

35
Q

What is a disaccharidase?

A

Specific enzymes that are secreted by the epithelial cells of the intestinal wall, that hydrolyse specific disaccharides.
e.g maltose, sucrose, lactose

(glycosidic bonds)

36
Q

Name the 3 disaccharidases and their function

A

-Maltase: (catalyses the hydrolysis of) maltose tho glucose

-Sucrase: () sucrose to glucose and fructose

-Lactase: () lactose to glucose and galactose

37
Q

What is a Dipeptidase?

A

An enzyme that catalyses the hydrolysis of the peptide bond joining the pairs of amino acids forming dipeptides- amino acids released.

(Proteins)

38
Q

What is an Endopeptidase?

A

-An enzyme that catalyses the hydrolysis of of the peptide bonds within protein molecules
-Broken down into smaller molecules of polypeptides or peptides.
-Found in the gastric and pancreatic juice, secreted by the cells of the small intestine.

(Protein)

39
Q

What is an Exopeptidase?

A

-An enzyme that catalyses the hydrolysis of peptide bonds linking the amino acids at each end of the polypeptide/peptide chain.
-Amino acids released, chain shortens until a dipeptide.
-Found in the pancreatic juice and secreted by the small intestine

(Protein)

40
Q

Where is bile made, stored, and released?

A

Made: Liver
Stored: Gall bladder
Released: Duodenum

41
Q

What is Emulsification of a lipid?

A

Breaks up lipids into tiny droplets called micelles, which increase the surface area to which the lipase can react.

42
Q

What emulsifies lipids?

A

Bile salts in bile juice

43
Q

What is protease in the stomach called?

A

Pepsin

44
Q

How is the surface area of the small intestine increased?

A

-The wall has folds called villi, so increases the rate of absorption.
-The surface of the epithelial cells lining villi also have small folds called microvilli.

45
Q

Where are monosaccharides and amino acids absorbed?

A

Begins in the duodenum, but most occur across the wall of the ileum.

46
Q

Describe the passage of monosaccharides and amino acids into the bloodstream

A

-Passes through the plasma membrane of each epithelial cell
-Across each cell
-Through the opposite side of each cell
-Through the plasma membrane of the cells of the wall of a capillary blood vessel.

47
Q

Describe the structure of the capillary network in villus

A

There is a network of capillary blood vessels and lacteal vessels in each villus that run to the hepatic portal vein and into the lymphatic system.

48
Q

Explain how co-transport is used to transport monosaccharides and amino acids across the plasma membrane

A

-Sodium ions are actively transported out of the cell and into the bloodstream, creating a conc gradient for sodium ions to move from the lumen to the cell via facilitated diffusion. This is done by the sodium potassium pump, using ATP.

-As the sodium ions are transported in, glucose or amino acids move into the cell at the same time, using a carrier protein.

-Now the conc is higher for glucose/amino acid in the epithelial cell and can diffuse down the conc gradient into the bloodstream, using facilitated diffusion and a carrier protein.

49
Q

Explain how glycerides and fatty acids are absorbed, through the plasma membrane

A

-They combine with bile salts and then emulsify to micelles.

-Micelles are delivered to the surface of the epithelial villi cells, via movement of the lumen.

-Micelles breakdown, releasing their contents for diffusion into the villi.

-Vitamins A and D, and cholesterol are also transported there by micelles.

-Within the villus cells, triglycerides are re-esterified on the smooth endoplasmic reticulum from fatty acids and monoglycerides, then transported to the golgi apparatus.

-In the golgi apparatus, triglycerides are modified and combined with proteins. They are packaged in an envelope of protein, cholesterol, and phospholipids, called Chlomicrons, that pass out via exocytosis.

-They circulate in lymph of the lymphatic vessels, and drain into the left subclavian vein via the thoracic duct.

50
Q

Monosaccharides and amino acids pass into the hepatic portal vein to be transported in the blood stream- to go where?

A

The liver

51
Q

What is the role of bile?

A

-Neutralises excess stomach acid in the duodenum
-Emulsifies fats
-Optimum pH for enzymes

52
Q

What is the Alimentary Canal?

A

All the parts of the body where food passes through mouth to rectum; everything else is an accessory (e.g liver).

53
Q

What 3 parts make up the small intestine and what order are they in?

A

1.Duodenum
2.Jejunum
3.Ileum

54
Q

What do micelles contain?

A

Bile salts
Fatty acids
Monoglycerides/glycerol

55
Q

What is the role of micelles?

A

-Make fatty acids more soluble in water
-Maintain a high conc of fatty acids to the cells lining the ileum.
-Carry fatty acids and glycerol to the cell.

Biology🧬 (9 decks)

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