BIOL10002 Lecture Notes - Chyme, Microbiota, Jejunum
Week 8
Lecture 21
Digestion, part 1
Significance of nutrition
affects gene expression
health and prevention of disease
Humans are heterotrophs; we obtain our carbon skeletons from food because we cannot synthesise organic
compounds
Plants are autotrophs; they can synthesise organic compounds
What we need
Carbohydrates; provide energy via ATP, stored as glycogen
Proteins; building blocks are amino acids
Fats; provide more energy via ATP as carbon chains are longer
Minerals; macronutrients and micronutrients
Vitamins; coenzymes for biological functions
Vitamin B1 (thiamine) deficiency: husk of rice removed but the husk contains most nutrients, which are made to
metabolise the carbohydrates in the white rice part
Amino acid deficiency: impairs protein synthesis
Fatty acids – also required in diet, especially linoleic acid
+ All other subclinical effects
The essential amino acids are:
Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine
Types of eating
Saprobes: eat dead organisms
Detritovores: eat waste products
Filter feeders: trap tiny particles or organisms suspended in water
Predators: catch and kill organisms
Females need 1,300-1,500 kcal/day at rest
Males need 1,600-1,800 kcal/day at rest
Diet is not one size fits all i.e. 1 Cal of cake =/= 1 Cal vegetables
1 kcal=1 Cal, 1 Cal=1000 cal
Obesity
An animal with insufficient caloric intake is undernourished and must metabolize its stored glycogen, fat, and
finally its own protein.
Overnutrition in humans can also be a serious health hazard – caused by diet, social and lifestyle factors, genetics
and epigenetics; can cause infertility
Leptin – a protein produced by fat cells to tell the body to stop eating
decrease in leptin = decrease in appetite
- receptors found in ventromedial hypothalamus
- mutation in leptin/low amounts of leptin = obesity BUT most obese people have an abundance of leptin as it is
produced by fat cells so an injection of leptin is not a effective cure for obesity
Lipids stored as triglycerides in adipose tissue
Proteins stored as amino acids
Glucose stored as glycogen (polysaccharide) in the liver
Lecture 22
Digestion, part 2
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Humans are heterotrophs; we obtain our carbon skeletons from food because we cannot synthesise organic compounds. Plants are autotrophs; they can synthesise organic compounds. Carbohydrates; provide energy via atp, stored as glycogen. Fats; provide more energy via atp as carbon chains are longer. Vitamin b1 (thiamine) deficiency: husk of rice removed but the husk contains most nutrients, which are made to metabolise the carbohydrates in the white rice part. Fatty acids also required in diet, especially linoleic acid. Isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Filter feeders: trap tiny particles or organisms suspended in water. Diet is not one size fits all i. e. 1 cal of cake =/= 1 cal vegetables. An animal with insufficient caloric intake is undernourished and must metabolize its stored glycogen, fat, and finally its own protein. Overnutrition in humans can also be a serious health hazard caused by diet, social and lifestyle factors, genetics and epigenetics; can cause infertility.
