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Nutrition Flashcards

1
Q

What is an autotroph

A

Organisms that synthesise complex organic molecules from inorganic raw material such as carbon dioxide and water. They are referred to as producers on food chains. Can be photoautotrophic or chemoautotrophic

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2
Q

What is a heterotroph

A

Organisms that can’t make their own food and obtain complex organic molecules by consuming other organisms. Can be referred to as consumers in food chains. Can be holozoic, parasitic, or saprotrophic

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3
Q

Explain how organisms feed using extra cellular digestion

A

Excretion of digestive enzymes
Digestive enzymes degrades substrate
Digested food absorbed by hyphae

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4
Q

Explain Amoeba’s nutrition

A

Single celled.
Large surface area to volume ratio & short diffusion distance.
Obtain all nutrients they need by simple diffusion, facilitated diffusion or active transport across their cell membranes:
Use endocytosis to take in larger molecules and microbes, which forms food vacuoles inside the cell.
Vacuoles fuse with lysosomes & contents are digested by lysosomal enzymes.
The useful products of digestion are absorbed into cytoplasm & the waste products Hester by exocytosis.

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5
Q

Explain nutrition in Hydra

A

Single body opening.
Related to sea anemones, corals & jelly fish.
Lives in fresh water.
Diploblastic.

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6
Q

What does diploblastic mean

A

made of two layer of cells:
Ectoderm (outer layer)
Endoderm (inner layer)
Layers separated by jelly layer containing a network of nerve fibres.

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7
Q

Explain how a tube gut affects nutrition.

A

Many animals have an anterior & posterior end and a digestive system that is a tube with two openings.
Food ingested at the mouth and indigestible water is egested at the anus.
More complex animals have guts are subdivided into different sections that perform different roles.

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8
Q
A
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9
Q

Summarise hydra’s anatomy and its gain of nutrition

A

Tentacles- photosynthetic algae in cells of tentacles (ectoderm), provides with sugar,
-Sting cells to kill prey and move food to mouth
Jelly layer- neutral network
Mouth/anus- inject/egest
Hypostome- can do phagocytosis and digest intracellularly in food
Endoderm layer- secreted protease and lipase for extracellular digestion
Basal disc- uses to attach to surface

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10
Q

Why must food be digested

A

Food molecules are too big and insoluble to cross membranes to get from the gut to the blood stream.

Polymers must be converted into monomers so that the monomers can be built into molecules needed by the body

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11
Q

What is peristalsis

A

Process that moves food along the gut in one direction.
Wave of muscular contraction moving food down the gut

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12
Q

What is ingestion

A

Taking food into the body via bicycle cavity

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13
Q

What is digestion

A

Breaking down food by hydrolysing

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14
Q

What is absorption

A

Absorption of small soluble products into bloodstream

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15
Q

What is assimilation

A

Building digestion products into new tissue/storage products

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16
Q

What is Heston

A

Removing undigested food

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17
Q

What is excretion

A

Removing metabolic waste

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18
Q

Provide examples of mechanical digestion

A

Chewing food in mouth
Churning in the stomach

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19
Q

Provide examples of chemical digestion

A

Salivary amylase breaking down starch into maltose in mouth
Pepsin breaking down proteins into peptides in stomach
Lipase breaking down lipids into fatty acids and glycerol in small intestine

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20
Q

In the gut wall, what does the serosa do

A

It’s a protective connective tissue

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21
Q

In the gut wall, what does the outer longitudinal muscle do

A

Relaxes in front of food

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22
Q

In the gut wall, what does the circular muscles do

A

Contract behind food, moving along

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23
Q

In the gut wall, what does the submucosa do

A

They contain vessels to remove food, lymphatic vessels to remove lipids, and nerves to stimulate peristalsis

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24
Q

In the gut wall, what does the mucosa do

A

Secretes mucus to protect cells from pH change and lubricate food

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25
In the gut wall, what does the epithelium do
Contains enzymes for digestion
26
What do dipeptidases do
Break down dipeptides into single amino acids
27
What do exopeptidases do
Remove terminal amino acids from ends of a polypeptide chain. Products = free amino acids
28
What do endopeptidases do
Hydrolyse peptide bonds in middle of polypeptides Products = short chain polypeptides. They also create more ends for exopeptidases to hydrolyse
29
How does the buccal cavity help mechanical digestion
Food is mixed with saliva by tongue, and chewed with teeth using force from jaw muscles. This increases surface area of food exposed to enzymes, increasing their efficiency
30
How does the buccal cavity help chemical digestion
Occurs due to release of saliva, which contains amylase, HCO^3- and CO3^2-, mucus for lubrication of food when swallowing
31
How does the oesophagus help digestion
Carries food to the stomach using peristalsis
32
How does the stomach help digestion
Food is kept in the stomach by the contraction of two sphincters at each end of the stomach. Cardiac sphincter at the top & pyloric sphincter at the bottom.
33
How does the stomach help mechanical digestion
Stomach wall muscles do churn food and mix it with gastric juices
34
How does the stomach help chemical digestion
Release of gastric juice
35
In the gastric pit, in the stomach, how does mature mucus help digestion
Produces cells
36
In the gastric pit, in the stomach, how does zymegen help digestion
They’re the chief cell. Secretes enzymes
37
How does the duodenum’s 3 regions help digestion
-the duodenum where it connects to the stomach and completes digestion -the jejunim where the bulk of absorption takes place -the ileum where it attaches to the large intestine and absorption is completed
38
How does the plyoric sphincter help digestion
It’s located at the base of the stomach and relaxes to allow food through to the dudodenum
39
How does the liver and pancreas link to the duodenum and aid digestion
They’re both attached to the duodenum and secrete chemicals down ducts into the food as it passes through
40
How does the liver secreting bile aid digestion
The liver secretes bile down the bile duct and the pancreas secretes pancreatic juice down the the pancreatic duct
41
Where is bile made
The liver makes bile which is stored in the gall bladder and then passes down the bile duct to the duodenum
42
What’s the purpose of bile
Contains bile salts which are amphipathic (have hydrophilic and hydrophobic parts) allowing them to emulsify fats Alkaline which neutralises acid in food coming from stomach Provides optimum pH for enzymes in small intestine
43
Explain where pancreatic juice is
Secreted by cells from the islets of langerhans. These cells are found in exocrine glands in the pancreas, which makes digestive enzymes (around the outer part of the islet). The inner part of the islet is made of endocrine cells, which secretes hormones
44
What’s the difference between exocrine and endocrine cells
Exocrine cells secretes hormones directly into bloodstream to regulate body functions Endocrine cells secrete substances into ducts leading to a specific location
45
What’s the purpose of pancreatic juice
-Contains digestive enzymes such we trypsin, amylase and various other proteases and lipases -Contains sodium hydrogen carbonate which provides alkaline optimum pH for pancreatic enzymes -Contains sodium hydrogen carbonate which neutralises acid from stomach
46
How do you describe the digestion of any food molecule (steps)
1) Name all enzymes involved 2) Which organ(s) makes the enzyme 3) Where is the enzyme operating 4) What bond is being hydrolysed 5) Products
47
Explain trypsinogen and its conversion to trypsin
Trypsinogen is an inactive enzyme secreted by the pancreas. Enterokinase in the duodenum converts it into active trypsin. Trypsin digests proteins and activates other enzymes. Activation prevents pancreatic self-digestion. Positive feedback mechanism converts more trypsinogen.
48
What are Brunner’s glands
Situated in the submucosa of the duodenum that secretes alkaline mucus to help neutralise stomach acid in food and protect the epithelium from stomach acid
49
How is the mucus secreted from brunners glands
Through depressions in the mucosa of the small intestine known as crypts of lieberkuhn The crypts secrete digestive enzymes
50
What do villi on epithelial cells lining the ileum do
Synthesise digestive enzymes
51
How are villi adapted for effective absorption of food molecules
Large surface area- villi and microvilli increase absorption. Rich blood supply– maintains a steep concentration gradient. Thin walls– short diffusion distance. Membrane-bound enzymes– aid digestion. Carrier proteins– enable active transport and facilitated diffusion. Lacteals– absorb lipids into the lymphatic system.
52
Where are some peptidases secreted during digestion?
Some are secreted into the lumen, while others are attached to the cell membranes of villi.
53
What is the role of dipeptidases in digestion?
They are attached to cell membranes and break down dipeptides into amino acids.
54
How do membrane-bound carbohydrases aid digestion?
They break down disaccharides into monosaccharides for absorption.
55
How are some disaccharides absorbed?
They are absorbed directly into epithelial cells and digested intracellularly.
56
Why are enzymes such as pepsin and trypepsin secreted as inactive precursors
To prevent them from digesting cells that produce them
57
Why is it necessary to release amylase in the small intestine if it was already released in the mouth
Amylase is destroyed by stomach acid. Pancreatic amylase then continues starch digestion for absorption
58
What is a parasite
Live in/on an organism from another species, obtaining nourishment at the hosts’s expenses causing harm/death
59
What is an endoparasite
An organisms that parasites inside another species
60
What is and ectoparasite
An organism that parasites inside another another species
61
What issues would a gut tapeworm face
Acidic environment in stomach Digested mucus and enzymes Food moving through Has to evade immune system Peristalsis & mechanism movements
62
Describe the lifecycle of taenia
Pigs (secondary host) can eat food contaminated with human faeces containing the tapeworm eggs Eggs hatch in pig and egg embryos (larvae) move through intestinal wall into pig muscles, remaining dormant as cysts Humans (primary host) eat undercooked infected pork Tapeworms grow from cysts inside human gut and live inside small intestine
63
How are tapeworms adapted for its lifestyles
Hook and sucker- attach itself firmly to hosts intestines Long and thin proglottid- large SA:V ratio & short diffusion distance to absorb nutrients Thick cuticle- protects from hosts enzymes Resistant egg shells- increasing chance of offspring
64
What’s the affects of pork tapeworm on people
Taeniasis- abdominal pains and weakness. Can be treated with drugs and prevented with improved sanitation, meat inspection. If humans consumes eggs directly rather than through eating infected pork, dormant embryos can form cysts in various organs (eyes, brain) and damage tissues
65
What are pediculus
Lice- ectoparasites Live on the body surface of their hosts
66
Why must lice be transferred from one host to another by direct contact
So it can ensure their continued survival & reproduction
67
Explain lifestyle of a louse
Adult louse lay eggs, 1-2 weeks later hatch into nymphs The empty egg case are called nits Nymphs grows into adult after 10 days, feeding on blood sucked from the host

Biology (13 decks)

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