Test 2 Flashcards
Food supplies organisms with…
-raw material for growth and repair
-energy for the cells -> metabolism
-resources needed to fight against disease and stay healthy
Two types of nutrition
-autotrophic
-heterotrophic
“A balanced diet provides all the…
“A balanced diet provides all the nutrients, in the correct amounts, needed to carry out the life process”
The opposite of balanced diet
Mal nutrition
What is rickets
Softening and weakening of bones because of malnutrition
What causes rickets
lack of vitamin D and Calcium
What is a balanced diet?
Provides all the nutrients in correct amounts needed to carry out the different life processes
What does a balanced diet consist of?
- lipids
- carbohydrates
- proteins
- (Nucleic acids)
- vitamins and minerals (needed in small amounts, essential for the efficient use of other nutrients)
What percentage of water is in the human body?
+- 70%
Why is water needed?
-Important for transporting substances/metabolism
*you need at least 1.5 litres of water per day
What is fibre
The indigestible part of vegetables, cellulose -> cell wall
What do we need fibre for?
It’s important for digestion by stretching the muscle of the gut and helping the food along
*shortage of fibre = constipation
How is energy measured?
Joules or Calories
- 1 calorie = 4.2 J
What are the three main energy providing organic molecules?
Fats - 39 kj/g
Carbohydrates - 17 kj/g
Proteins -20 kj/g
Energy is needed for metabolic reactions, depending on 3 factors. What are they?
Basal metabolic rate
Activity or exercise
Digestion, absorption and storage of nutrients
What is the basal metabolic rate
The process of staying alive (thinking, breathing, temperature regulation, circulation)
What are factors influencing nutritional needs?
1.Age
2.gender
3.weight and height
4.growth periods
5.physical activity
6.pregnancy
Salivary glands
Produce saliva -> H2O, amylase
Action of pushing food and water down to organs
Peristalsis
What is mechanical digestion
-By teeth and tongue
- by stomach movements (food mixed)
What is chemical digestion
By enzymes (WS3)
Hydrolysis
Enzymes convert large, complex molecules into small, soluble molecules which can be absorbed
Absorption
-Most of the absorption of the nutrients into the blood or lymph takes place in the ileum ( 3 part of small intestine)
Absorption -> adaptions of the ileum to its functions
- Very long (5m) -> enough time for absorption
- Highly folded surface (longer surface area for absorption)
- Villi
- Micro villi
- epithelium only one of a cell thick -> short distance for absorption
- capillaries in the villus
Absorption -> adaptions of the ileum to its functions pt2
1.capillaries in the villus -> fast absorption of nutrients into the blood stream/ lacteal -lymphatic system
2.absorption of water: in the colon
3.storage of faeces until defecation: in rectum
important functions of the liver
-absorbs food nutrients (amino acids and glucose) are first sent to the liver via hepatic portal vein
-liver sorts out these molecules and provides them in ideal concentrations to the different parts of the body
define human respiratory system
breathing is a biophysical process involving inhaling and exhaling to supply the respiratory system with O2 for -> cellular respiration
Gas exchange in alveoli by diffusion:
movement of molecules from a high concentration to a low concentration
LEARN DIFFUSION DIAGRAM
nostril
passageway for air
nasal cavity
-filters lined with ciliated goblet cells (cellular?)
- warms
-moistures air
mouth
passageway for air and food
pharynx
common passage way for food and air
epiglottis
covers the larynx
larynx
air passes through here during breathing. when breathing out, the vocal can be made to vibrate. The sound produced create our speech.
trachea
tube that carries air towards the lungs. C-shaped rings of cartilage prevent the trachea collapsing during inhalation.
bronchus
first branch from the trachea. There is one bronchus to each lung
bronchiole
final, very fine branch leading into alveolus
alveoli
these are lined by the membranes where gas exchange takes place. The surface is moist, thin and has an enormous area.
*in humans the total surface area is about as big as a tennis court
diaphragm
helps you inhale and exhale
homogenus
a mixture/ a solution
pepsin
breaks down food
acids act as a disinfectant for food in you stomach
saliva
contains salivary amylase to digest starch/ polysaccharides into maltose (dissach.), mucus to lubricate food and hydrogen carbonate (alkaline) -> ideal ph for amylase to work
what is the best approximate ph for amylase to work
alkaline
gastric juice
-hydrochloric acid (HCl) provides acidic conditions (ph2) for pepsin and kills microorganisms
-mucus protects the wall of the stomach from HCl
pancreatic juice
container enzymes (proteases, lipases, amylases) and hydrogen carbonate which neutralises the acidity from the stomach to ph8
bile
emulsifies the fats: converts them from large globules to smaller droplets, giving greater surface area for lipases to attack
why is diffusion simple
-Simple diffusion does not require energy
*Diffusion is a type of transport that simply occurs when there is a concentration difference where the molecules move from a region of higher concentration to a region of lower concentration
