Biology π | Human nutrition | 7 Flashcards
if you are confused this is a quirky name for the human nutrition chapter
What sex has the higher energy requirement on average?
Male.
Do adults or teenagers have a higher energy requirement on average?
Teenagers.
Do pregnant women, or non pregnant women have a higher energy requirement on average?
Pregnant women.
What is a balanced diet?
It consists of all the food groups / nutrients in the correct proportion
What are all the nutrients we need?
Carbohydrates, proteins, vitamins, minerals, fibre, lipids, water.
What food can we find carbohydrates in and why?
In fruits and vegetables because of respiration. Also in rice and pasta.
What food group gives us the most energy?
Lipids, even more than carbohydrates.
What is the role of carbohydrates as a nutrient?
It is a source of energy in respiration.
What is the role of proteins?
Growth, repair, muscle formation, and enzymes.
What is the role of fats as a nutrient?
Store of energy, insulation, making of cell membranes.
What is the role of water in the body?
Solvent, regulates body temperature, maintains osmostic pressure in cells
What is the role of fibre in the body?
Helps the digestive system function properly, slows down and helps movement of food.
What is the role of vitamin C in the body?
Vitamin C helps formation of collagen in skin and gums
What is the role of vitamin D in the body?
Helps absorb calcium from food for strong bones and teeth.
Where do you find vitamin C?
Citrus fruits
Where do you find vitamin D?
Fish, nuts, and vegetables
What is the deficiency disease of Vitamin C?
Scurvy (pain in joints and muscles; bleeding from gums and other places)
What is the deficiency diseases for vitamin D?
Rickets (bones become soft and deformed)
What are the two main mineral nutrients?
Iron and Calcium
What is the role of iron in the body?
To produce haemoglobin
What is the role of calcium in the body?
To make bones
Where do you find minerals?
Red meat, fish, meat, green vegetables - Iron
Dairy, bread - Calcium
What can eating too much saturated fat lead to?
Fat deposit build up in arteries due to cholesterol, leading to coronary heart disease or blood clot that could lead to a heart attack.
Why do we have to digest?
The nutrients we need are found in large molecules which are in big pieces of food. Digestion breaks down all of this food.
What is physical digestion?
The breaking down of large pieces of food into smaller ones to increase surface area without chemical change to the food molecules.
What is chemical digestion?
The breaking down of large molecules of food into smaller ones by enzymes.
Where does physical digestion take place?
In the mouth by teeth, churning movements of alimentary canal, and emulsification from bile.
Where does chemical digestion take place?
Stomach, small intestine, and mouth.
Where do we produce saliva?
Salivary glands.
What is the alimentary canal?
A long tube running from one end of a body to the other, from the mouth to the anus.
What is the role of the mouth?
Teeth mechanically break down food; saliva makes the mixture more liquid and contains salivary amylase to break down carbohydrates.
What is the role of the esophagus?
It transports and passes down food to the stomach.
What is the stomach and its role?
It is a muscular sac that contracts its walls to push food, producing pepsin to break down protein and produces hydrochloric acid.
What is the small intestine and its role?
It is where food is squeezed into after the stomach. The digested food is absorbed into the bloodstream. It used enzymes to aid digestion, from the pancreas and bile from the gall bladder.
Where is bile produced?
Liver.
What is the purpose of the gallbladder?
It stores bile from the lungs and releases it.
What is the pancreasβ role?
It produces many digestive enzymes.
What is the large intestine and its role?
Consisting of the rectum and colon, this is where a lot of indigestible food is left from the small intestine, and excess water is absorbed and feces is left behind in the rectum.
What is ingestion?
The taking in of substances (eg food and drink), into the body through the mouth.
What is absorption?
The movement of small food molecules and ions through the wall of the small intestine into the blood.
What is assimilation?
The movement of digested food molecules into the cells of the body where they are used.
What is egestion?
The passing out of food that has not been digested or absorbed as feces, through the anus.
What is the purpose of physical digestion in the mouth?
We cannot swallow large food at once, the saliva makes the food more watery, making particles move more freely and increasing diffusion. Most importantly, physical digestion increases surface area of food for enzymes to work faster.
What are the types of teeth?
Incisors, canines, premolars, molars.
What is the function of incisors?
They are chisel shaped teeth for biting out chunks of flesh and helping with ingestion
What is the function of canines?
They are sharper teeth that help to rip flesh.
What is the function of premolars?
They are large wide surfaces for grinding and chewing food, increasing surface area.
What is the function of molars?
Larger; also for grinding and chewing food, increasing surface area.
What is bile used for?
To digest lipids and neutralize chyme.
How does bile help to digest lipids?
Food contains lipids that stick and dont mix, bile breaks down these lipids into small pieces to increase the surface area for lipase.
What is the process where bile breaks down lipids called?
Emulsification
Does bile have any enzymes?
No
What are the propetrties of bile?
Yellow-green, alkaline, and watery.
Where is bile produced and how does it reach the lipids?
Made in the liver, it is stored in the gallbladder where it flows down the bile ducts into the duodenum of the small intestine.
What are the parts of a tooth?
Enamel, Cement, jawbone, pulp cavity, nerves, blood vessels
.
What is the enamel?
The hardest outer layer of a tooth - the hardest tissue in the human body. It is for protection.
What is the dentine?
The layer below the enamel, more yellow and like bone. It contains channels with living cytoplasm.
What is the pulp cavity?
Below the dentine, containing nerves and blood vessels, it supplies oxygen to the dentine cytoplasm.
What is the tooth cement?
At the root of the tooth, fibres grow out of it to attach to the tooth to the jawbone.
What is the jawbone?
The bone below the gums of the teeth.
Why do we need both physical and chemical digestion?
Food particles need to be broken down enough that they can be absorbed into the blood stream, physical digestion cannot do all this but aids chemical digestion by increasing a particleβs surface area.
What is starch converted to?
To maltose and then further converted to glucose.
What is the encapsulating term for enzymes that break down proteins?
Protease.
What enzyme breaks down lipids?
Lipase.
Why are there two different enzymes for breaking down protein?
Pepsin breaks down protein in the stomach and trypsin breaks down protein in the alkaline solutions of the small intestine.
Where is amylase produced?
Salivary glands and pancreas
Where is pepsin produced?
Stomach epithelium (goblet cells)
Which enzymes are used in the small intestine duoduem?
Trypsin, lipase, and maltase.
Which enzyme breaks down maltose?
Maltase
Which enzyme breaks down starch?
Amylase
What are the products after breaking down protein?
Polypeptides and amino acids
What are the optimum pH conditions for amylase?
6-7 pH
What are the optimum pH conditions for Pepsin?
2 pH
What are the optimum pH conditions for Trypsin, lipase, and maltase?
8 pH
`What are the two parts of the small intestine?
Duodenum and ileum.
What is the difference between the duodenum and ileum?
In the duodenum, enzymes and bile is secreted. However, no new enzymes are added in ileum but they remain on the cells covering the villi to spread. More absorption happens here.
What is the use of mucus in the alimentary canal?
Mucus acts as a lubricant and forms a cover over the inner surface of the alimentary canal, preventing enzymes from digesting the bodyβs own cells.
How does the small intestine increase surface area?
There are spike like projections of villi all over the walls, which have micro villi to further increase surface area.
How does the small intestine absorb nutrients into the bloodstream?
In the villi, water, amino acids, sugars, fats, vitamins and minerals are diffused and actively transported into the aorta bloodstream and then the blood is returned to the liver by the hepatic portal vein.
How does the small intestine absorb lipids?
Digested fats are diffused into the lacteals, leading to the lymph, lymphatic vessels, and eventually the heart.
What are the cells that produce mucus on villi?
Goblet cells.
What are microvilli?
Cells lining the villi, that further increase the surface area, covered by mucus that contains enzymes.
What are the small intestineβs adaptations other than villi.
The small intestine, when stretched out, is actually 5m long in an adult human, which gives lots of time for digestion. The villi walls are one cell thick so digested nutrients can easily reach blood capillaries and lacteals.
What are vitamins?
ORGANIC substances which are only needed in tiny amounts. Lack of them can cause a deficiency disease.
What are minerals?
INORGANIC substances that are only needed in small quantities.
Why donβt vitamins and minerals need to be digested before absorption?
They are already small molecules which can pass through walls of the ileum.
What physical digestion happens in the stomach?
Strong muscular walls contract to churn the food, creating chyme.
Why does our stomach have hydrochloric acid?
It kills bacteria and is the right pH environment for pepsin to work.
Where is most water absorbed?
In the small intestine, less in the large intestine.
