more surface area and gas exchange (p1)

Question 1

During digestion, large biological molecules are _________ to
smaller molecules that can be _______ across cell membranes

Answer 1

During digestion, large biological molecules are hydrolysed to
smaller molecules that can be absorbed across cell membranes

Question 2

Digestion in mammals of:
* carbohydrates by ____________ and membrane-bound __________________
* lipids by lipase, including the action of _______ salts
* proteins by ____________, exopeptidases and membranebound ______________.

Answer 2

Digestion in mammals of:
* carbohydrates by amylases and membrane-bound
disaccharidases
* lipids by lipase, including the action of bile salts
* proteins by endopeptidases, exopeptidases and membranebound dipeptidases.

Question 3

Mechanisms for the absorption of the _______ of digestion by cells
lining the ileum of mammals, to include:
* __________ mechanisms for the absorption of amino acids
and of monosaccharides
* the role of micelles in the absorption of lipids.

Answer 3

Mechanisms for the absorption of the products of digestion by cells
lining the ileum of mammals, to include:
* co-transport mechanisms for the absorption of amino acids
and of monosaccharides
* the role of micelles in the absorption of lipids.

Question 4

why are large biological molecules in food (e.g starch and proteins)broken down during digestion?

Answer 4

-they are too big to cross cell membranes
-meaning they can’t be absorbed from the gut into the blood
-so are broken down into smaller molecules (e.g glucose and amino acids) which can cross cell membranes
-which can easily be absorbed into the blood and transported arounf the body for use by body cells

Question 5

proteins are hydrolysed into………..

Answer 5

amino acids

Question 5

how are larger molecules broken down into smaller molecules during digestion?

Answer 5

hydrolisis reactions-bonds are broken by adding water

Question 6

carbohydrate are hydrolysed into………..

Answer 6

simple sugars (mono and disaccharides)

Question 7

lipids are hydrolysed into………..

Answer 7

fatty acid and monoglycerides (glycerol)

Question 8

parts of the digestive system

Answer 8

mouth,salivary glands,oesophagus,stomach,liver,gall bladder,bile duct,pancreas,small intestine large intestine,rectum ,anus ,appendix

Question 9

liver function

Answer 9

produces bile

Question 10

mouth

Answer 10

teeth break down food into small pieces increase SA:V ratio.
carbohydrate digestion starts here.
food shaped into bolus (ball) by tongue and lubricated by saliva allowing it to be swallowed easily.

Question 11

oesophagus

Answer 11

hollwo tube, with muscular walls allowing food to pass from mouth to the stomach
contractions in smooth muscle in wall help move food down to stomach

Question 12

stomach

Answer 12

protein digestion begins here
glandular tissue producing enzymes and stomach acid
muscular tissue churns food mixing it with enzymes and stomach acid
acid helps unravel proteins to enable enzymes to work
low pH is optimal for stomach enzymes to work and is detrimental to many microorganisms which may be in food

Question 13

small intestine

Answer 13

3 sections: duedenum,jejunum and ileum
food goes through the lumen
smooth muscle wall which rythmically contracts (peristalsis)moving the food along
carbohydrate,lipid and protein digestion occurs mainly in the duedenum, with enzymes made in pancrease and small intestine
soluble food molecules absobed into blood through wall via diffusion and active transport in the jeunum and illeum
illeum is long and lined with vili increasing th SA
absorbs water

Question 14

large intestine

Answer 14

any water remaining in food that can’t be digested (e.g cellulose found in plant fibres) absorbed here aswell and vits and minerals
undigested food material (faeces) stored in rectum and removed through anus

Question 14

digestive enzymes

Answer 14

used to break down biological molecules in food, there are a variety of different enzymes produced by specialised cells in the digestive system of mammals .since enzymes only work with a specific substrate different enzymes are need to catalysed the break down of different food molecules. digestive enzymes are extracellular there are 3 main types:lipases, carbohydrases , and proteases

Question 15

digestive enzymes are extracellular

Answer 15

they work out;side the cell

Question 16

what enzymes aid the digestion of carbohydrates?

Answer 16

amylase and disaccharidases

Question 17

amylase

Answer 17

-produced in salivary gland (releases into mouth) and the pancreas (released into the small intestine)
-catalyses the break down of starch, by catalysing the hydrolysis reactions which break the glycosidic bonds in the starch to produce moltose
-maltose is then hydrolysed by maltase

Question 18

moltose is hydrolysed by…….

Answer 18

maltase

Question 19

membrane bound disaccharidases

Answer 19

-enzymes attached to sell membrane of epithelial cells lining the ileum.
-helps break down disaccharides into monosaccharides by the hydrolysis of their glycosidic bond
-monosaccahride can be transported acroos the membrane of epithelial cells lining the ileum through specifc transport proteins

Question 20

what disaccharidase breaks down sucrose?
What are the monosaccharides sucrose is broken into?

Answer 20

sucrase
glucose and fructose

Question 21

what disaccharidase breaks down maltose?
What are the monosaccharides maltose is broken into?

Answer 21

maltase
glucose and glucose

Question 22

what disaccharidase breaks down lactose?
What are the monosaccharides lactose is broken into?

Answer 22

lactase
glucose and galactose

Question 23

where does digestion of lipids solely take place?

Answer 23

small intestine

Question 24

lipase enzymes

Answer 24

catalyse the break down of lipids into monoglycerides and fatty acids. involves the hydrolysis of ester bonds in lipids lipases mainly produce by pancreas and secreted into the small intestine where they act

Question 25

bile salts

Answer 25

-produced by the liver and emulsify lipids, causing lipids to form small droplets -this increase the surface area, that is available for lipases to work on -once lipid is broken down by lipase, the monoglycerides and fatty acids stick to the bile salts and form structures called micelles -which helps the products of lipid digestion be absorbed

Question 26

where is bile made and stored?

Answer 26

made in the liver stored in the gall bladder

Question 27

proteins are broken down by a combination of different peptidases. these are enzymes that catalysed the conversion of proteins into amino acids by hydrilysing the peptide bond between the amino acids- these include endopeptidases and exopeptideases

Answer 27

proteins are broken down by a combination of different peptidases. these are enzymes that catalysed the conversion of proteins into amino acids by hydrilysing the peptide bond between the amino acids- these include endopeptidases and exopeptideases

Question 28

where does protein digestion begin

Answer 28

stromach

Question 29

endopeptidases

Answer 29

break the bonds within a protein creating smaller size protein pieces secreted with hydrochloric acid

Question 30

partially digested food moves from the stomach to the small intestine. fluid secreted by the pancreas travels to the small intestine and helps___________the acidic mixture, this pancreatic juice contains endopeptides and ______________

Answer 30

partially digested food moves from the stomach to the small intestine. fluid secreted by the pancreas travels to the small intestine and helps neutralise the acidic mixture, this pancreatic juice contains endopeptides and exopeptides

Question 31

exopeptidases

Answer 31

hydrolyse peptide bonds at the end of protein molecules. removing single amino acids from molecules

Question 32

dipeptidases

Answer 32

exopeptides that work specifically on dipeptides. work to separate the 2 amino acids by hydrolysing the peptide bond between them.often located in the cell membrane of the epethilial cells liing the ileum. amino acids are release into the cytoplasm of the cell/absorbed.

Question 33

where is amylase produced?

Answer 33

salivary gland and pancrease

Question 34

where are dissacharidases produced?

Answer 34

small intestine

Question 35

where is Endopeptideases produced?

Answer 35

stomach and pancrease

Question 36

where is exopeptidases produced?

Answer 36

pancreas

Question 37

where is dipeptidases produced?

Answer 37

small intestine

Question 38

where is lipase produced?

Answer 38

pancreas

Question 39

where is amylase released ?

Answer 39

mouth and small intestine

Question 40

where is maltase released ?

Answer 40

small intestine

Question 41

where is endopeptidase released ?

Answer 41

stomach and small inestine

Question 42

where is exopeptidase released ?

Answer 42

small intestine

Question 43

where is lipase released ?

Answer 43

small intestine

Question 44

the products of digestion are absorbed across the ileum epithelium and into the blood stream

Answer 44

the products of digestion are absorbed across the ileum epithelium and into the blood stream

Question 45

glucose is absorbed by co-transport with _______ions via a co-___________ protein. galactose is absorbed in the same way using the same transporter protein. fructose is absorbed via ________ diffusion via a different transporter protein.

Answer 45

glucose is absorbed by co-transport with sodium ions via a co-transporter protein. galactose is absorbed in the same way using the same transporter protein. fructose is absorbed via facilitated diffusion via a different transporter protein.

Question 46

co-transport mechanism for the absorption of monoasaccharides:

Answer 46

1.glucose carrier proteins in the cell surface membran of the small intestinr transport glucose molecules only when sodium ions are present 2.sodium ions and glucose molecules are co-transported into the epithelial cell via facilitated diffusion 3.glucse molecules diffuse across the epithelial and enter the capillary and the other end by facilitated diffusion 4.the concerntration gradient of sodium ions is maintained by actively transporting sodium ions out of the epithelial cell and into the blood

Question 47

__________ help move monoglycerides and fatty acids towards the epithelium. because micelles constantly break up and reform they can release monoglycerides and fatty acids allowing them to be absorbed-whole micells aren't taken up by the epithelium,. mono glyceride and fatty acids are _________soluable so can ________ quickly across the epithelial cell.

Answer 47

micelles help move monoglycerides and fatty acids towards the epithelium. because micelles constantly break up and reform they can release monoglycerides and fatty acids allowing them to be absorbed-whole micells aren't taken up by the epithelium,. mono glyceride and fatty acids are lipid soluable so can diffuse quickly across the epithelial cell.

Question 48

amino acids are absorbed via co-transport, in a simular way to glucose and galactose.sodium ions ________ transported out of the epithelial cell and into the blood,. creating a sodium ion _______. sodium ions can the diffuse from the _________ of the ileum into the epithelial cells through sodium-dependant transporter proteins, carrying the amino acid with them.

Answer 48

amino acids are absorbed via co-transport, in a simular way to glucose and galactose.sodium ions actively transported out of the epithelial cell and into the blood,. creating a sodium ion conerntration. sodium ions can the diffuse from the lumen of the small intestine into the epithelial cells through sodium-dependant transporter proteins, carrying the amino acid with them.

Question 49

co-transport mechanism for the transport of amino acids

Answer 49

1) specific amino acid co-transport proteoms found within the cell surface membrane pf the epithelial cells in th ileum 2) transport amino acid only when there are sodium ions presnt 3) for every sodium ions that is transported into the cell an amino acid is transported in 4)occurs via facilitated diffusion,requiring movement of molecules down the concerntration gradient 5)amino acids diffuse across epithelial cell and pass into blood via facilitated diffusion 6)conertration g of sodium ions from lumwn into epithelial cell maintained by active transport of sodium ions out the the epithelial cells and into the blood via a sodium potassium pump.

Question 50

The haemoglobins are a group of _______ similar molecules found in many different organisms. Haemoglobin is a protein with a ___________ structure.

Answer 50

The haemoglobins are a group of chemically similar molecules found in many different organisms. Haemoglobin is a protein with a quaternary structure.

Question 51

The role of haemoglobin and red blood cells in the transport of _____. The loading, transport and unloading of oxygen in relation to the oxyhaemoglobin ___________curve. The cooperative nature of oxygen binding to show that the change in ___________ of haemoglobin caused by binding of the first oxygens makes the binding of further oxygens ______________ . The effects of carbon dioxide concentration on the _____________ of oxyhaemoglobin (the Bohr effect).

Answer 51

The role of haemoglobin and red blood cells in the transport of oxygen. The loading, transport and unloading of oxygen in relation to the oxyhaemoglobin dissociation curve. The cooperative nature of oxygen binding to show that the change in shape of haemoglobin caused by binding of the first oxygens makes the binding of further oxygens easier. The effects of carbon dioxide concentration on the dissociation of oxyhaemoglobin (the Bohr effect).

Question 52

Many animals are ________ to their environment by possessing different types of haemoglobin with different oxygen transport _____________.

Answer 52

Many animals are adapted to their environment by possessing different types of haemoglobin with different oxygen transport properties.

Question 53

The general pattern of blood circulation in a mammal. Names are required only of the __________ arteries and of the blood vessels entering and leaving the heart, lungs and _______.

Answer 53

The general pattern of blood circulation in a mammal. Names are required only of the coronary arteries and of the blood vessels entering and leaving the heart, lungs and kidneys.

Question 54

The gross structure of the human heart. Pressure and volume changes and associated ________ movements during the cardiac cycle that maintain a ___________ flow of blood.

Answer 54

The gross structure of the human heart. Pressure and volume changes and associated valve movements during the cardiac cycle that maintain a unidirectional flow of blood.

Question 55

The structure of _________ and the importance of capillary beds as exchange surfaces. The formation of tissue _______________ and its return to the circulatory system

Answer 55

The structure of capillaries and the importance of capillary beds as exchange surfaces. The formation of tissue fluid and its return to the circulatory system

Question 56

haemoglobin

Answer 56

-human haemoglobin found in redblood cells -its role is to carry oxygen around the body -their are chemically simular types of heamoglobin found in different organsims all with the same role -heamoglobin is large protein with a Quaternary structure -each chain has a heam group which has an iron ion and gives heamoglobins its red colour -each molecule of human heamoglobin can carry 4 oxygen molecules

Question 57

quaternary structure

Answer 57

made of 4 polypeptide chains

Question 58

oxyhaemoglobin

Answer 58

-in the lungs oxygen associates with heamoglobin to form oxyheamoglobin -this is a reverible reaction, near body cells oxygen dissociates from oxyheamoglobin and turns back into haemoglobin

Question 59

association/loading

Answer 59

when an oxygen molecules joins to a haemoglobin

Question 60

dissociation/unloading

Answer 60

when an oxygen molecule leaves oxyaemoglobin

Question 61

reversible reaction for loading and unloading

Answer 61

..................loading Hb+4O2--------------------> HbO8 (oxyHb) <------------------- unloading

Question 62

affinity for oxygen

Answer 62

the tendency a molecule has to bind with oxygen

Question 63

haemoglobins _______ for oxygen varies depending on the conditions e.g pO2

Answer 63

haemoglobins affinity for oxygen varies depending on the conditions e.g pO2

Question 64

pO2 is a measure of the _______________ of oxygen in the air . The greater the concerntartion of oxygen dissolved in cells the ________ the pO2. as pO2 increases haemoglobins _________ for oxygen increases : -oxygen loads to form oxyheamoglobin where pO2 is _____ -oxyhaemoglobin unloads where pO2 is _____.

Answer 64

pO2 is a measure of the concerntration of oxygen in the air . The greater the concerntartion of oxygen dissolved in cells the higher the pO2. as pO2 increases haemoglobins affinity for oxygen increases : -oxygen loads to form oxyheamoglobin where pO2 is high -oxyhaemoglobin unloads where pO2 is low

Question 65

oxygen enters the capillaries at the alveoli in ____. they have a ______- pO2 so oxygen _____ onto haemoglobin to from oxyhaemoglobin. when cells respire they use up oxygen _____ the pO2. redbloods cells deliver oxyhaemoglobin to respiring tissues where it ____________ its oxygen. the heamoglobin then returns to the lungs to load more oxygen

Answer 65

oxygen enters the capillaries at the alveoli in lungs. they have a high pO2 so oxygen loads onto haemoglobin to from oxyhaemoglobin. when cells respire they use up oxygen lowering the pO2. redbloods cells deliver oxyhaemoglobin to respiring tissues where it unloads its oxygen. the heamoglobin then returns to the lungs to load more oxygen

Question 66

oxygen dissociation curve

Answer 66

- shows how saturated heamoglobin is with oxygen at a given partial pressure

Question 67

why is the oxygen dissociation curve s shaped?

Answer 67

-when the first oxygen binds to the heamoglobin it alters the haemoglobin's tertiary structure/shape -this uncovers the heam group binding sites making it easier for other o2 molecules to bind -but as the heamoglobin becomes more saturated it gets harder for oxygen to bind. (steep bit in the middle=where it is really easy for o2 molecules to bind , shallow bit at the end is where it gets harder)

Question 68

partial pressure of CO2 (pCO2)

Answer 68

measure of the conerntration of CO2 a cell

Question 69

bohr effect

Answer 69

-pCO2 affects oxygen unloading -oxygen gives up its oxygen more readility at high pCO2 -so more oxygen gets to cells durong activity -when cells respire they produce CO2 rasing the pCO2 -this increases the rate of oxygen unloading so the dissociation curve shifts right -the satuartion of heamoglobin with oxygen is lower at a given pO2 meaing more oxygen is being released

Question 70

an increased rate of ________ leads to an increasing the concentration of CO2 in the blood. this _____ the pH (making it more acidic). this reduces heamoglobins _________ for oxygen as it's shape/tertiary structure changes slightly. so haemoglobin will ________ oxygen faster to respiring cells.

Answer 70

an increased rate of resparition leads to an increasing the concentration of CO2 in the blood. this lowers the pH (making it more acidic). this reduces heamoglobins affinity for oxygen as it's shape/tertiary structure changes slightly. so haemoglobin will unload oxygen faster to respiring cells.

Question 71

different types of haemoglobin

Answer 71

differnt organisms have different types of haemoglobin with different oxygen transporting capacities - depending on things such as where they live , how active they are and their size. having a particular type of haemoglobin is an adpatation that helps an organism survive in a particular environment.

Question 72

haemoglobin for low oxygen environments

Answer 72

-organisms that live in envriomrnts with low oxygen concentration have heamoglobin with a higher affinity for oxygen than humans. -this is because their isn't as much oxygen available so haemoglobin has to be very good at loading any available oxygen -the dissociation curve is to the left of humans

Question 73

haemoglobin for high activity levels

Answer 73

-organisms that are very active have a high oxygen demand and have haemoglboin with a lower affinity for oxygen than human haemoglobin -this is because they need to easily unload oxygen so it available for them to use -their dissociation curve is to the right of human one

Question 74

haemoglobin for small mammals

Answer 74

-small mammals have a high SA:V ratio so loose heat quickly so have a high metabolic rate to help them stay warm so have high oxygen demand -mammals that are small than humans have heamoglovin with a lower affinity for oxygen because they need Hb that can easily unload oxygen to meet the high demands -their dissociation curve is to the right of humans

Question 75

function of the circulatory system

Answer 75

multicelluar organisms such as mammals have a low surfce area to volume ratio,so need a specialised mass transport system to tasnport raw materials from their specialised exchange organs to thir body cells

Question 76

structure of the circulatory system

Answer 76

-made up of the heart and blood vessels -heart pumps blood through blood vessels (arteries,arterioles,veins and capillaires) to reach different parts of the body] -

Question 77

general pattern of blood cirulcation on a mammal

Answer 77

-closed double circulatory system-blood passes through the heart twice for every circuit around the body -deoxygenated blood in right side of heart pumped to lungs oxygenated blood returns to left side -oxygenated blood in left of heart pumped to rest of the body and deoxygentaed returns right

Question 78

pulmonary artery

Answer 78

transports deoxygenated blood from heart to lungs

Question 79

pulmonary vein

Answer 79

transports oxygenated blood from lungs to heart

Question 80

aorta

Answer 80

transports oxygenated blood from heart to body

Question 81

vena cava

Answer 81

transports deoxygnated blood from body to heart

Question 82

renal artery

Answer 82

transports blood from body to kidneys

Question 83

renal veins

Answer 83

transports blood from kidneys to vena cava

Question 84

blood transports respiatory gases, products of digestion, metabolic waste and ___________ around the body.there are _____ circuits .one circuit takes blood from the heart to the _________ and back to the heart. the other loop take the blood to the rest of the body so the blood has to go through the heart _____ to complpete a full circuit.

Answer 84

blood transports respiatory gases, products of digestion, metabolic waste and hormones around the body.there are two circuits .on circuit takes blood from the heart to the lungs and back to the heart. the other loop take the blood to the rest of the body so the blood has to go through the heart twice to complpete a full circuit.

Question 85

hearts own blood supply

Answer 85

coronary arteries

Question 86

importance of double circulatory system

Answer 86

-prevents mixing of oxygenated and deoxygenated blood , so blood pumped around the body is fully saturated with oxygen for aerobic respiration -blood can be punmp around the body at high pressure after being lower pressure in the lungs so substances taken to and removed from body more efficently

Question 87

arteries

Answer 87

-carry blood from heart to the rest of the body -walls are thick and muscular and have elastic wall to stretch and recoil as the heart beats -has collagen providing strength and prevents vessel bursting or changing shape -the inner lining /endothelium is folded allowing the artery to stretch-also helps matain a high pressure -all carry oxygenated blood except the pulomary artery.

Question 88

arterioles

Answer 88

-arteries divide into smaller blood vessels, which form a network through the body -blood is directed to different areas of demand around the body by muscles in the arterioles which contract to restrict blood flowand relax to allow blood flow

Question 89

capillaries

Answer 89

arterioles branch into capillaries, which are smallest blood vessel. substances e.g o2 and glucose are exchanged between cells and capillaries so they are adapted for effcient diffusion: -foudn very near cells in exchange tissue e.f the alveoli in lungs so their is a short diffusion pathway -walls are only one cell thick (short d path) -large number of capillaries increase sa for gas exchange -networks of capilaires in tessure are called capillary beds -lumen very narrow allowing red b cells to be close to body cells

Question 90

veins

Answer 90

take blood back to the heart under low pressure. -they have wider lumen than arteries with very little muscle or elastic tissue ( little is needed as low pressure and thinner walls allow veins to be easily compressed aiding blood flow) -collagen prevent from bursting and maintains shape -have valves to prevnt the backflow of blood -blood flow through veins aided by contraction of body muscles surrounding them -all veins contain deoxygenated blood exc pulomonary vein

Question 91

composition and functions of blood

Answer 91

comp: plasma-mainly water transports substances in a solution red blood cells-carry oxygen white blood cells -immune platelets -involved in clotting function: -transports co2 and o2 -transports nuteints -trasnpts waste for excretion -hormone -trasnports clotting factors

Question 92

tissue fluid

Answer 92

fluid that surrounds cells in tissues. Made from small molecules that leave blood plasma e.g water, o2 and nuteins (contains no large proteins of red b cells unlike blood as too large to be pushed out capillary walls) cells take in oxyge and nuteints from tissue fluid and release metabolic waste into it .

Question 93

in a capillary bed substances move out the capillaries and into the capillary bed by ________ filtration

Answer 93

in a capillary bed substances move out the capillaries and into the capillary bed by pressure filtration