BIO Flashcards
What is the cell membrane
-Outermost membrane of cell
-Controls only some substances to enter
Functions of water
acts as a solvent for chemical reactions
Key component of tissues
Transports dissolved substances
Controls body temperature
What elements is carbohydrates made up of
CHO
what are single sugars
small molecules
can pass through the cell membrane and absorbed into cells
Glucose Fructose and Galactose
what are double sugars
made up of two single sugars molecules joined together
Maltose sucrose lactose
test for carbohydrates
Benedict test
what are the colours for Benedict test
blue = no amount
brick-red = large amounts
what are complex carbohydrates
large molecules
starch cellulose and glycogen
how to test for starch
iodine test
colours for testing starch
blue black for present
brown for absent
function of carbohydrates
source of energy
cellulose walls protect plant cell
sugars in nectar attract insects
what is fats made of
CHO
one glycerol + 3 fatty acids = fat molecule
how to test for fat
ethanol emulsion test
what are the colours of ethanol emulsion test
- clear = absent
- cloudy white emulsion = present
function of fats
- stores energy
- main component of cell membrane
- stored under skin for insulation
- stored around certain vital organs for protection
what are proteins
- made up of CHON
- Amino acids + polypeptides = proteins
- joined together with peptide bonds
- proteins are large molecules
- cannot pass through cell membrane
- digested into smaller molecules which are amino acids
Test for proteins
biuret test
colours for biuret test
violet = present
function of proteins
- synthesis of new protoplasm for growth and repair
- synthesis of antibodies
- synthesis of enzymes and some hormones
What is the steps of the digestive system
Mouth -> Pharynx ->Oesophagus -> Stomach -> Small Intestine -> Large Intestine -> Rectum -> Anus
How does the mouth digest food
- Teeth help to chew to help break up large pieces into smaller pieces
- Salivary glands secrete salivary amylase which digests starch into maltose
- Tongue mixes food with saliva
What is the oesophagus
- Narrow muscular tube
- Has a muscular wall which helps with the wave-like contractions to help push the food along the gut. This is called peristalsis
How does the stomach digest foods
- Stores food for long
- Contains gastric glands which produces gastric juice containing pepsin to digest proteins into polypeptides
- Also contains hydrochloric acid pH 2, providing a suitable medium for pepsin to work
How does the small intestine digest foods
- Contains intestinal glands which secrete intestinal juice (ILMP), Lipase digesting fats into fatty acids and glycerol, Maltase digesting maltose into glucose, Peptidase digesting polypeptides into amino acids
- Pancreas secretes pancreatic juice(PALT), Amylase digesting starch into maltose, Lipase digesting fats into fatty acids and glycerol, Trypsin digesting proteins into polypeptides
- Gall bladder releases bile
Large intestine
- Absorbs water and minerals salts
- No digestion takes place
- Stores undigested matter
- Rectum contracts to expel undigested matter or faeces through the anus called egestion
What is liver
- Produces Bile
- Breaks down alcohol
What is gall bladder
- Store bile
- Bile duct is connected to small intestine to transport bile
What is pancreas
- Connected to small intestine called pancreatic duct
- Transports digestive juice(PALT)
What is the digestion of starch
Starch -> (Amylase) Maltose -> Maltase -> Glucose
What is the digestion of fats
Fats ->(Lipase) -> Fatty acids + Glycerol
What is the digestion of proteins
Proteins ->(Pepsin,Trypsin) Polypeptides ->(Peptidase) -> Amino acids
What is bile
- Breaks up the fats into small fat globules this is called emulsification
- Increases surface area to volume ratio of the fats for faster digestion
- Bile is alkaline in nature and neutralises the acid from the stomach, Providing a suitable alkaline medium for the enzymes to work on
Adaptation of small intestine
- Inner surface folded and has many villi
- Each villus is covered by a membrane called epithelium which is one cell thick to provide short distance for substances to diffuse through
Absorption in small intestine
- Glucose and amino acids absorbed via diffusion and active transport into blood capillaries and villi
- Fatty acids and glycerol are absorbed into lacteals
- Water and mineral salts are absorbed into blood capillaries
Uses of glucose
- Releases energy for cell activities
- Excess glucose is stored as glycogen in the liver
- Lack of glucose in blood stream, liver will convert glycogen into glucose
Use of amino acids
- Make up proteins and enzymes
- assimilated, converting into new protoplasm
- Excess amino acids deaminated into urea in the liver
What is Hepatic Portal Vein
Transport blood rich in glucose and amino acids from the small intestine to the liver
