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Biology > Nutrition and Digestion Topic 5 1st year > Flashcards

Nutrition and Digestion Topic 5 1st year Flashcards

1
Q

What is nutrition?

A

Nutrition is the way by which an organism processes nutrients to obtain energy for respiration, growth and repair.

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2
Q

There are 2 types of nutrition. Mention and explain them.

A

Autotrophic and heterotrophic

Autotrophic: Organisms which build up their own food from inorganic molecules like plants carry out photosynthesis or some types of bacteria

Heterotrophic : organisms which are unable to synthesize their own food They obtain ready made food which has been synthesized from autotrophs.

(Feed on sources of carbon)

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3
Q

What is holozoic nutrition?

A

Applied mainly to animals which have a digestive tract called the alimentary canal

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4
Q

Which animals are holozoic and why are they holozoic?

A

Carnivores
omnivores
herbivores

Most animals are holozoic because they ingest the food and break it down by enzyme action. The unwanted wastes are then egested

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5
Q

Define carnivores, omnivores and herbivores

A

Carnivores:organisims which feed only on meat like lions or dogs

Omnivores: organisims which feed on both meat and plants like: bears or humans

Herbivores:organisims which feed on plants only. like deer or cows

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6
Q

What are parasites?

A

Living organisms which feed on other living hosts and cause them harm

ex: lice or tapeworm

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6
Q

What are decomposers/saprophytes?

A

Organisms that obtain their food from dead decaying organic matter. ex: some bacteria and fungi.

They mainly focus on breaking down dead decaying organims

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7
Q

What are detritivores?

A

Detritivores are living organisms which feed on small organic debris generally left by saphrotrophs.

These are also decomposers. So they help saphrophytes

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8
Q

Why cant food be absorbed directly in heterotrophic organisms?

A

Because food consists of large insoluble food molecules which are too complex and first need to be broken down by mechanical and chemical digestion into simpler and soluble food molecules to be able to be absorbed by the body.

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9
Q

What are the 2 types of digestion?

A

Mechanical and chemical

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10
Q

Define digestion.

A

Digestion is the breakdown of large insoluble food molecules making them into small soluble food molecules so that they can be absorbed in the bloodstream. This si done by mechanical and chemical digestion

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11
Q

True or false.
The body cannot absorb food directly because the food first needs to be broken down into simpler substances

A

True

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12
Q

How are carbohydrates, lipids and proteins absorbed in the body?

A

carbohydrates:simle sugars
lipids: glycerol and amino acids
proteins: amino acids

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13
Q

True or false.
Simple substances like vitamins ,mineral and water also need to be broken down.

A

False.

If they are simple substances they do not need to be broken down because they are already in a usable form that the body can absorb.

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14
Q

Define the alimentary canal.

A

A long coiled and muscular tube which runs from the mouth to the anus. Food is taken in and ingested through the mouth, wastes are egested through the anus. The alimentary canal is specialized to perform different functions

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15
Q

What are the different steps of digestion along the alimentary canal?

A

Ingestion
Digestion
Absorption
Assimilation
Egestion

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16
Q

Define ingestion.

A

The act of taking complex organic food into the alimentary canal through the mouth

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17
Q

Define absorption

A

The process where digested food molecules passes from the alimentary canal through the bloodstream. It involves the uptake of soluble food molecules into the bloodstream across a cell membrane

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17
Q

Define assimilation

A

Assimilation is the use of soluble food molecules by cells in the body. It consists of the incorporation of digested food molecules into all the cells of the body.

For example amino acids are built up into proteins

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18
Q

Define egestion

A

The removal of undigested food from the alimentary canal(from the body)

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19
Q

Distinguish between intracellular and extracellular digestion

A

Intracellular digestion: in simple organisms like amoeba, digestion takes place inside the cell. Soluble food is absorbed directly into the cytoplasm of the cell. Indigestible material is egested

Extracellular digestion: food enters the alimentary canal, then the food is broken down by enzyme action (digestive enzymes are released along this tube),after soluble food molecules can be absorbed into the bloodstream through a cell membrane. It is known as extracellular digestion because it is taking place outside of all the cells in the body.

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20
Q

True or false.

Enzymes are always in an active form

A

False.

Enzymes are inactive and then they are changed into active catalysts

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21
Q

What would happen if enzymes in the stomach are always active? How does the stomach protect itself?

A

If enzymes in the stomach are always active then ulcers could form, but this doesn’t happen because the stomach produces mucous

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22
Q

What is a macromolecule?

A

A large molecule consisting of repeated subunits called monomers.

In digestion ,it needs to be broken down to form a micro molecule

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23
What are digestive reactions in the body called?
Catabolic reactions and they are usually hydrolysis reactions involving hydrolytic enzymes (addition of water)
24
In the body there are different enzymes which are specialized to break different substrates. Mention the types of substrates that these enzymes act upon: proteases,lipases,carbohydrases,amylases,nucleases and peptidases.
Proteases: proteins ex:trypsin or Lipases:lipids : lipase carbohydrases: carbohydrates: sucrase,maltase,lactase nucleases: nucleic acids amylases: starch (salivary amylase) peptidases: break down polypeptides
25
What is an epithelium?
1 layer of cells, which are continuously being replaced by worn out cells
26
Draw a diagram of the alimentary canal
27
Know how to label the parts of the digestive system
28
Distinguish between mechanical and chemical digestion
Mechanical: also known as physical. This involves breaking food into small pieces by chewing it and churning it up with no chemical change. It involves breaking down food physically Chemical digestion: the breakdown of large molecules into smaller ones by water and digestive enzymes. Large molecules are made into smaller and simpler forms
29
Since enzymes are made in cells, where are enzymes stored in the digestive system?
In glands (extracellular enzymes)
30
What can we also call the mouth?
The buccal cavity
31
What happens when food is ingested through the first part of the alimentary canal?
Digestion takes place in the mouth first. The mouth contains a neutral ph of 7 Both mechanical and chemical digestion are taking place inside of the mouth. Mechanical digestion: teeth are present. Chewing takes place which involves breaking down the food into smaller fragments which also increases the surface area for the enzymes to work Chemical digestion: saliva and water (mucous) are present which contains salivary amylase produced by salivary glands
32
Mention some functions of saliva.
Lubricates the food for swallowing Dissolves soluble food Contains the enzyme salivary amylase, which changes starch into maltose
33
What is the wet and food "ball" called which has been made in the mouth during the first part of digestion by mechanical and chemical digestion?
Bolous
34
How is the food swallowed and pushed back so it can reach the oesophagus?
The tongue helps to lubricate the food and it is pushed back. A muscle flap called the epiglottis closes the trachea during swallowing. This prevents the bolous from reaching the lungs and prevents choking.
35
What closes the nasal passage during swallowing?
The soft palate
36
After swallowing where does the bolous go?
Oesophagus The oesophagus is a pipe which connects the mouth to the stomach.
37
What makes it easier for the bolous of food to go down the oesophagus?
Peristalsis Mucous and saliva. They act as a lubricant to help the food go down the gullet easily
38
What is peristalsis?
Since the walls of the gullet are made of muscle, a ring of muscular motion and contraction moves downwards which helps the bolous go down the stomach
39
What are the muscles in the oesophagus called?
Circular and longitudinal muscles When the circular muscles contract the longitudinal relax and vice versa
40
What is the role of teeth during digestion and why is this important?
Teeth break down food into smaller fragments. This increases the surface area for the enzymes to work properly
41
Mention the 4 types of teeth
Incisors Canines Premolars Molars
42
Mention the structure and function of each tooth.
Incisors: located at the front of the mouth,chisel-shaped and are responsible to cut and bite food. Canines: located behind the incisors,pointy shaped and are responsible to tear ,pierce and grasp the food Premolars: located behind the canines, flattened with cusps and are responsible to grind and crush food Molars: located behind the premolars,flattened with cusps and are also responsible to crush and grind food
43
How can teeth be further divided?
Milk teeth or permanent teeth. Milk teeth are teeth during childhood. Permanent teeth replace the milk teeth from age 6 onwards Teeth can also be divided into the crown and the root The crown : the part which is found above the gums The root: the part which is found below the jaw bone
44
Mention the different layers of the tooth
Enamel Dentine pulp These 3 make up the crown The rest make up the root: cement, jaw bone fibres nerve and blood vessels, (the gums are present between the root and the crown)
45
Mention some functions of each component.
Enamel: the hardest substance in the body. made up of calcium phosphate which is needed for healthy teeth. The enamel covers the crown of the tooth Dentine: found beneath enamel. dentine contains living tissues. Dentine also contains calcium phosphate and is also a hard substance but not as hard as enamel Pulp: centre of the tooth. it contains living tissues which are sensitive to heat or cold.It also contains the blood vessels which bring food and oxy gen to the tooth The root is made up of a hard substance called cement. The fibres connect the jaw bone and the tooth togther
46
Mention 2 types of diseases which affect teeth
Tooth decay: which can cause holes in the tooth And gum disease which can cause teeth to fall out
47
What causes these types of diseases?
Plaque. This is caused by saliva food and bacteria which form naturally on the teeth. This damages the calcium salts of the enamel.
48
How can we prevent gum disease?
Brushing teeth regularly Going to the dentist often Reduce the intake of sugary foods or soft drinks
49
What do we call animals with the same type of teeth and animals with teeth specialized for different functions?
Same teeth: homodont Different teeth: heterodont
50
What can we find in the stomach?
The stomach is a muscular bag whcih produced hydrochloric acids,pepsinogen and mucous
51
What are the 2 types of sphincters found in the stomach?
Cardiac and pyloric Cardiac: allows the bolus of food into the stomach Pyloric: allows digested food molecules into the duodenum
52
What do gastric glands in the stomach secrete?
Gastric juice
53
What does gastric juice contain?
Mucous hydrochloric acid pepsinogen
54
Mention the function of each component in the gastric juice.
Mucous: helps to lubricate the food and help them protect the walls of the stomach from the acidic hydrochloric acid Hydrochloric acid: converts the inactive enzyme pepsinogen into the active enzyme pepsin. Hydrochloric acid also provides the optiumu pH for the enzyme to work. It can also kill any harmful bacteria or foreign bodies ingested Pepsinogen: changes into pepsin
55
On what enzyme does the enzyme pepsin act upon?
Protein
56
What does the enzyme pepsin break?
Proteins into peptides
57
What do we call the food when it is in the stomach?
chyme
58
How does the stomach carry out physical digestion?
The stomach mixes and churns the food by muscular contraction with the walls of the stomach.Making it into chyme
59
True or false. When the bolus enters the stomach,the pyloric sphincter is closed
True. The food also stays in the stomach for about 3 to 4 hours,to not overload the digestive system with too much food
60
When the pyloric sphincter allows the chyme to pass through, where does it enter?
Te first part of the small intestine called the duodenum
61
True or false. When the chyme passes into the duodenum it has a ph of 7
False It is acidic
62
How is the small intestine divided?
Duodenum (the first part of the small intestine most of the digestion takes place here. the duodenum is also connected to the liver and the pancreas Jejunum: between the duodenum and the iluem Ileum:final absorption and digestion takes place here
63
From which structures does the small intestine receive juices and enzymes to aid in digestion?
Liver Pancreas Intestinal glands
64
What does the liver produce and where is it stored?
The liver produces bile and it is stored in the gallbladder
65
What is bile?
Bile is a green chemical that breaks down fat. Its colour is caused by bile pigments
66
What are bile salts?
Bile salts are found in bile and this is what helps bile to break down large fat droplets making them into smaller ones. This is called EMULSIFICATION
67
What is the role of the pancreas?
The pancreas is a gland. The pancreas secretes pancreatic juice which is secreted from the pancreatic duct into the duodenum
68
What does the pancreatic juice contain?
Sodium hydrogen carbonate 3 enzymes: trypsin,pancreatic amylase and pancreatic lipase
69
Mention the functions of every component found in the pancreatic juice.
The sodium hydrogen carbonate neutralizes the acidic pH of the chyme since it is in the stomach. (sodiumhydrogencarbnate is an alkaline solution) In the duodenum, the enzymes work best at a neutral ph Trypsin breaks down protein into polypeptides Pancreatic amylase breaks down starch into maltose Pancreatic lipase breaks down fats into fatty acids and glycerol
70
After the chyme has been broken down by the enzymes in the pancreatic juice and has been neutralized by the sodium hydrogen carbonate, it moves on to the ileum. What do the intestinal glands in the ileum secrete?
This is when the final digestion takes place. The intestinal glands secrete 3 other enzymes called: maltase,sucrase and lactase Maltase breaks down maltose into glucose and glucose Sucrase breaks down sucrose into glucose + fructose Lactase breaks down lactose into glucose and galactose IMP LIPASE AND PEPTIDASES ARE ALSO PRESENT IN THE INTESTINAL GLANDS They break down the chyme further fat is broken down by the lipase making them into fatty acids and glycerol Peptidases break the POLY further into amino acids
71
What enzyme changes trypsinogen into trypsin? (the active form of the enzyme)
enterokinase
72
What enzymeS breaks down nucleic acids in the small intestine?
Nuclease and nucleotidase Nuclease breaks down nucleic acids into nucleotides Nucleotides are further broken down by nucleotidase to form phosphates , nitrogenous bases,and pentoses
73
How does the small intestine protect itself from the active enzymes?
Mucous
74
After digestion in the ileum has taken place, what have been all the nutrients converted to now?
Proteins into amino acids Fats into glycerol and fatty acids Carbohydrates into monosaccharides
75
Now how do these nutrients get absorbed into the bloodstream? (Where does absorption take place?)
In the ileum, specifically in the villus by active transport or by passive diffusion
76
How is the ileum adapted to absorb such nutrients?
Very large surface area because it is very long, and also has specialised structures called villi. The villi greatly increase the surface area Each villus has a rich blood supply (blood capillaries are present)as well as a lacteal (lymphatic system) for the absorption of food molecules. The epithelium of the villus is one cell thick, which make it very quick for the food molecules to get absorbed, as well as microvilli are present on each epithelial cell which again greatly increases the surface area
77
How are the digest food molecules going to enter the lacteal and the blood capillary?
The digest food molecules are going to enter the lacteal and the blood capillaries by simple diffusion. However some of the water,minerals,vitamins and digest food can also be transported by active transport
78
What does the blood capillary form? And where does this blood vessel transport the digest food molecules?
Hepatic portal vein which is going to carry digest food molecules from the intestines to the liver
79
What happens after these soluble food molecules get transported to the liver?
The digested material is going to be stored in the liver,and will be transported to all the cells in the bloodstream where they will be assimilated by the cells.
80
Why are vitamins and minerals important?
Vitamins are important because they help to process metabolic chemical reactions,because they can act as cofactos for enzymes. Minerals are important because they help to conduct electrical impulses,control other bodily functions and build up structures such as bones
81
What does the lacteal branch into?
The lympathic system
82
Draw a labelled diagram of a villus.
83
What happens to any undigested material which has not been absorbed by the villus?
They will be passed on to the large intestine (colon)
83
True or false. In the colon enzymes are secreted.
False. No enzymes are secreted
84
What are some other extra structures that are present in the colon?
Caecum and appendix
85
Do the caecum and the appendix have any functions in humans or mammals?
In humans these strctures do not have any digestive functions,however in the grass-eating mammals these strctures contain cellulose digesting bacteria breaking it down into glucose.
86
What is present in the colon?
Water and any undigest material. Example: dead cells,bacteria,mucous bile salts. However some of the water and ble salsts do get absorbed back into the the blood capillary
87
Where does the faeces pass through?
The rectum
88
Name a function of the rectum
The rectum stores feaces before it is egested.
89
How does the feaces get "helped" to be egested from the body?
By perstalis (muscular contractions) By mucous which aids in lubrication + the opening of the anal sphincter The feaces get egested from the anus
90
What bioloigcal term do we use to describe when the feaces get egested out through the anus?
Defeacation
91
During assimilation,what happens to nutrints like glucose when they are sent to the liver via the hepatic portal vein from the ileaum?
It all depends on the blood glucose level. Glucose is the main source of energy.Its needed for respiration.This is needed to drive everything that happens in the body. Excess glucose is converted into glycogen in the liver. Excess glycogen is converted into fats and stored under the skin When the blood glucose level is unbalanced the liver converts glycogen into glucose and releases in the blood to keep the level of glucose balanced.
92
What happens to the fatty acids and glycerol assimilated?
Most of the fatty acids are absorbed via the lacteal and then get assimilated in the bloodstream in all body cells. Fats are needed to build up strctures like cell membranes Needed for heat insulation Important for cell metabolism (respiration) they provide twice the ammount of energy Can be stored under the skin and protect delictae organs like the heart or the kidneys
93
Mention what happens to proteins after they are assimilated?
1)Proteins are needed to build up structures in the cell membrane 2) Needed for enzymes 3) Excess proteins are toxic in the body so they become deamined.Excess nitrogen is chnaged into ammonia ,then urea and then deaminated as urine.
94
Name the 3 blood vessels involved in digestion.
Hepatic artery:bring oxygenated blood to the liver from the aorta hepatic portal vein: transports digest food material fom the ileum to the liver heptaic vein: blood from the liver to the venacava
95
Mention some functions of the liver
1) builds protein from amino acids 2) Detoxification: liver breaks down poisionous substances circulating in the blood ex: alcahol or drugs 3) Conversion of fats into glycogen 4) Deamination 5) Produces bile
96
What is a balanced diet?
It involves the daily recommeneded optium intake of energy from carbohydrates,proteins,fats,vitamins,minerals,fibre and water to main good health
97
Define malnutrition
Dietry imbalance due to deficiency or excess intake of a nutrient State of poor nutrition and it can result from an unbalanced diet or the inability to absorb food
98
Define undernutrition
Lack of proper nutrients over a period of time Example:not eating enough could cause the body to not work properly for all the living processes to be carried out in the body
99
Define overnutrition
When there are more nutrients required for normal growth
100
What diseases are caused when there is a deficiency of vitamin A and D?
A:night blindness D: rickets in children
101
What can excess vitamins in the body cause?
Hypervitaminosis : pain in the muscles and bones
102
What causes excess carbohydrates?
obesity or diabetes
103
What causes a lack in carbohydrates?
Starvation or kwashiorkor
104
What can cause a lack of vitamin C?
Scurvy
105
Lack of calcium or iron?
Osteoporosis and anaemia
106
Lack of iodine?
Thryoid gland enlargement
107
Lack of fluoride?
Tooth decay
108
What are the increased conditions for people who are obese?
Lots of conditons: heart diesease,problems with joints,dibatees,heart attacks cancer etccccc

Biology (19 decks)

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