animal nutrition

Question 1

What does a balanced diet provide?

Answer 1

an adequate intake of the biological molecules and energy needed to sustain the body and ensure good health and growth
It contains: carbohydrates, proteins, fats, vitamins, minerals,water and fibre
These provide energy, growth and repair, and to regulate the body’s metabolism

Question 2

What is basal metabolic rate

Answer 2

Energy required for body functions, even if you lie down and do very little you still need it lolzies
It varies from person to person but on average an adult needs 7000kj/day

Question 3

Why can fat be bad for us

Answer 3

Saturated fats increase blood cholesterol which is linked to narrowing of the arteries and heart disease.
Cholesterol is a chem made in liver

Question 4

Carbohydrates as a source of nutrients

Answer 4

sugar and starches
Ready source of energy that is easily respired.
Simple sugars area absorbed by the stomach into the blood almost immediately . Energy released as a result of respiration

Question 5

Proteins as a source of nutrients

Answer 5

Growth and development.
You digest proteins into amino acids and then use these to make your own proteins
If protein isn’t used for growth and repair it may be respired to provide energy

Question 6

Fats as a source of nutrients

Answer 6

Important as long term energy store. Fat is stored under the skin and around fat and organs. One gram of fat releases more than twice the energy than one gram of carbs or protein

Question 7

Water as a source of nutrients

Answer 7

Makes up two thirds of your body mass.

Needed for chemical reactions to take place in solution.

Question 8

Vitamins and minerals

Answer 8

VitC tissue repair- scurvy
VitD-strengthens bones and teeth-rickets and osteomalacia
Iron-formation of hemoglobin in red blood cells-anaemia
Calcium-Same as vitD

Question 9

Fibre

Answer 9

Can’t be digested, adds bulk to food, helps movement of food in alimentary canal by peristalsis.
Fibre absorbs poisonous wastes from bacteria in our gut

Question 10

What is energy output

Answer 10

Energy your body uses in a day. If energy input is greater than output, fat is stored in the body and body mass increases. We may run the risk of becoming overweight or obese

Question 11

Major causes of obesity

Answer 11

High intake of fatty foods and refined foods containing a lot of added sugar
Too little exercise
Social and emotional stress leading to comfort eating

Question 12

Problems with obesity and identifying obesity

Answer 12

More likely to have health problems like heart disease, high blood pressure, diabetes caused by high blood sugar and arthritis

Ppl who are 20% above the recommended weight for their height
Having a BMI greater than 30
BMI=body mass/kg divided by height/meters^2

Question 13

What causes constipation

Answer 13

A diet lacking in roughage/fibre

Question 14

What happens to the body during starvation

Answer 14

Draws upon stores of carbs, fat and protein for energy
bMR is reduced
The body uses stored fat and then breaks down muscle wasting and an emaciated appearance

Question 15

What is protein energy malnutrition(PEM)

Answer 15

Caused by lack of dietary energy and protein
And lead to kwashiorkor or marasmur two different ways in body responds to lack of food
in both feeding should involve frequent servings of small quantities of food as PEM causes cells in the pancreas and intestines to die so fewer digestive enzymes are secreted

Question 16

Symptoms of kwashiorkor

Answer 16

Oedema, swelling of abdomen and legs
Sparse dry hair
Flaky skin
Fat accumulation in the liver

Question 17

Symptoms of marasmus

Answer 17

Very low body mass
Thin arms and legs
Little muscle or fat
Wizened/old looking face

Question 18

Ingestion

Answer 18

Taking of substances into the body through the mouth

Question 19

Digestion

Answer 19

The breaking down of large insoluble molecules into small soluble molecules so that they can pass through the gut wall into the blood

Question 20

Absorption

Answer 20

The movement of small food molecules and ions through the wall of the intestine into the blood

Question 21

Assimilation

Answer 21

Movement of digestive food molecules into the cells of the body where they are used, becoming part of the cells

Question 22

Egestion

Answer 22

The passing out of food that has not been digested or absorbed, as faeces through the anus

Question 23

Mechanical digestion

Answer 23

The breakdown of large pieces of food into smaller pieces of food without changing food molecules
eg: chewing, muscle contractions in the stomach, small intestine large globules of fat broken into smaller globules by emulsification by bile

Question 24

Chemical digestion

Answer 24

The breakdown of large insoluble food molecules into smaller soluble molecules by the action of enzymes.
Occurs in mouth stomach and small intestines
Enzymes in alimentary canal: proteases, carbohydrases and lipases

Question 25

Proteases

Answer 25

Protein molecule made up of many different amino acids | protease enzymes break down protein molecules | amino acids

Question 26

Carbohydrase

Answer 26

Carbohydrase enzyme that breaks down starch is amylase Starch molecules made up of many glucose molecules | Amylase enzyme breaks down starch to maltose(a sugar) | Glucose

Question 27

Lipase

Answer 27

``` Fat molecule made up of fatty acid and glycerol molecule | Lipase breaks down fat molecule | fatty acids + glycerol ```

Question 28

Teeth, function and them all

Answer 28

Carry out mechanical digestion, 32teeth, increase surface area making it easier for enzymes to catalyze the reactions needed for chem digestion Incisors: chisel-shaped for biting and cutting Canines pointed for piercing and tearing Premolars: have uneven cusps for grinding and chewing Molars like premolars for chewing food

Question 29

Anatomy of a tooth

Answer 29

Divided into crown and root Enamel forms hard outer layer, part above gum Inside is the softer dentine, more like bone structure A layer of cement fixes root into bony socket in jaw Pulp cavity is space in tooth containing nerves and blood vessels

Question 30

What is tooth decay caused by

Answer 30

Bacteria mixes with saliva to form plaque, changes sugar to acid that attacks the enamel and dentine of the tooth

Question 31

How can tooth decay be avoided

Answer 31

By regular brushing with a good toothbrush, avoiding sugary foods, and visiting the dentist regularly

Question 32

What does saliva contain

Answer 32

Made in the salivary glands Mucus; slimy substance that lubricates passage of food bolus down the throat Amylase; enzyme that catalyses the breakdown of starch to maltose

Question 33

How does food pass down the oesophagus

Answer 33

Oesophagus has circular and longitudinal muscles in its wall Food passes down by a wave of muscular contractions called peristalsis The circular muscles contract and longitudinal muscles relax behind the food bolus to pass it along

Question 34

How is digestion carried out in the stomach

Answer 34

Stomach is a muscular bag that holds about 1l of food When food reaches the stomach... Walls of stomach make gastric juice contains protease pepsin starts digestion of proteins into smaller molecules called polypeptides Also contains hydrochloric acid: -Kills bacteria in food, low ph denatures the enzymes in any harmful microorganisms in the food -acid ph of 1.5-2 gives optimum conditions for the action of pepsin Mixture of all this is called Chyme, muscular walls churn up the food to mix it well, takes 2-3hrs , contents now a runny liquid Ring of muscle (pyloric sphincter) opens to let food pass into the duodenum

Question 35

What does pancreatic juice contain

Answer 35

Amylase Trypsin-protease that breaks down protein and polypeptides to Peptides Lipase-breaks down fats to fatty acids and glycerol Sodium hydrogencarbonate an alkali that neutralizes the acidic food

Question 36

What enters the duodenum

Answer 36

By the pancreatic duct, pancreatic juice | By bile duct, bile (yellow-green fluid made liver and stored in the gallbladder)

Question 37

What is bile and what does it do

Answer 37

Bile is alkali and also neutralizes the acid given to the food in the stomach, gives the best ph for enzymes in the small intestine to work Bile emulsifies fats by breaking down large gobules of fats into smaller globules. These have a larger surface area over which lipase can act to break fat down

Question 38

What is the function of the cells lining the ileum

Answer 38

They make enzymes that complete digestion of food Proteases- peptides to amino acids Sucrase which breaks down sucrose to glucose and fructose Then maltose is broken down by maltase to glucose on the membranes of the epithelium lining the small intestine

Question 39

How is the small intestine adapted for absorption

Answer 39

``` very large surface area of 9 square meters -possible as its v long and has folded inner lining w/ millions of villi, and the epithelial cells have microscopic projections called microvilli these vastly increase absorptive area Thin lining (one cell thick) so digested food can easily cross the wall into the blood and lymph ```

Question 40

Absorption in the small intestine

Answer 40

Digested food(simple sugars, amino acids, fatty acids and glycerol) pass through the wall of the small intestine by diffusion/active transport Digested food reaches the capillaries and lacteals in villi. Absorbed food molecules are quickly transported to the live by the hepatic portal vein Fatty acids and glycerol are transported in the lymph

Question 41

What happens when food gets to the colon

Answer 41

There is not much useful food left, mainly fibre, dead cells, bacteria and water The solid waste is stored in the rectum, eventually are excreted as faeces through the anus, this is egestion

Question 42

What is cholera

Answer 42

Water-borne disease caused by bacterium vibro cholerae Main symptom is diarrhoea as a result of dehydration Tends to occur in areas where there is lack of proper sanitation or unclean water supply Cholera is transmitted by ingestion of water or food that is contaminated by faecal matter containing the bacteria

Question 43

Effects of cholera on the body

Answer 43

Almost all bacteria killed in stomach but some reach small intestine and burrow thru the mucous lining the wall of the intestine and produce a toxin Molecules of this toxin enter epithelial cells of intestinal wall, disrupting functioning of cell surface membrane of ep cells. Chloride ions pass out of the cells into intestinal lumen. This creates a water potential gradient. Water flows by osmosis from cells and body into lumen. Movement of ions and water from blood into the lumen cause dehydration and diarrhoea

Question 44

What is oral rehydration therapy

Answer 44

A solution that contains: Water to rehydrate the blood and other tissues Sodium ions to replace ions lost from blood and tissue fluid Glucose to provide energy for the active uptake of sodium ions from the intestine Other ions such as potassium and chloride to replace lost ions Water Alone isn’t enough as it isn’t absorbed by intestine and doesn’t contain ions Lost