y9 content Flashcards
What are the small basic units of fats/lipids, proteins, glucose and starch?
fats/lipids –> 3 fatty acids and one glycerol
proteins –> amino acids
glucose –> N/A
starch –> glucose
What are the testing methods for fats/lipids, proteins, glucose and starch?
fats/lipids –> add ethanol then water
positive result: clear to white emulsion
proteins –> biurets solution
positive result: blue to purple
glucose –> benedict’s solution (+heat)
positive result: blue to brick red
starch –> iodine solution
positive result: orange to blue/black
What are the key differences between starch and glucose?
Glucose is a soluble monosaccharide (one sugar)
Starch is an insoluble polysaccharide (many sugars)
Single molecule of glucose: C6H12O6
Starch is long chains of this molecule.
What role does amylase play in digestion?
Amylase is found in our saliva and breaks down starch into maltose.
What role do the teeth play in digestion?
Teeth break down food, increasing surface area for enzymes to work.
What is the name of the process of squeezing bolus down the oesophagus and how does it work?
Peristalsis squeezes the bolus down into the stomach. Peristalsis is the involuntary contraction and relaxation of longitudinal and circular muscles throughout the digestive tract.
How does the stomach physically digest food?
Food is churned in the stomach, further breaking it down and increasing its surface area for enzymes to work.
How does the stomach chemically digest food?
Hydrochloric acid in the stomach kills pathogens in the food.
Pepsin (a protease) breaks down protein into amino acids
Low optimum pH for enzyme function
How does the duodenem contribute to digestion?
Gall bladder releases bile which emulsifies lipids (large surface area) and neutralises the acids.
Pancreas releases enzymes (tripsin, lipase, amylase) in the pancreatic juice
How does the illum contribute to digestion?
The illum has a big surface area, short diffusion distance and high concentration gradient.
Nutrients absorb into the bloodstream and then assimilates out.
What happens in the large intestine?
Excess water is removed.
What is egestion?
Faeces leaves the rectum through the anus.
What is MRS C GREN?
Movement: can change position
Reproduction: can have offspring either sexually or asexually
Sensitivity: can detect stimuli, such as light, and respond to them
Control: can control their internal environment (homeostasis)
Growth: can increase mass
Respiration: can produce energy either aerobically or anaerobically
Excretion: can remove waste substances of metabolic reactions
Nutrition: can absorb nutrients in order to use them for growth and repair
What is a eukaryote?
Eukaryotes are organisms that have a nucleus and organelles that are found within a plasma membrane.
What is the function of the nucleus?
- contains genetic material, the DNA which codes for a particular protein
- enclosed in a nuclear membrane
What is the function of the cytoplasm?
- liquid substance in which chemical reactions occur
- contains enzymes
- organelles are found in it
What is the function of the cell membrane?
- contain receptor molecules to identify external signals
- selectively controls what enters and leaves the cell
What is the function of the mitochondria?
- where aerobic respiration reactions occur, providing energy for the cell
What is the function of the ribosomes?
- where protein synthesis occurs
- found on a structure called the rough endoplasmic reticulum
What are the four different types of eukaryote?
Plants, animals, fungi, protoctists
Multicellular: plants, animals, fungi
Unicellular: protoctists, fungi
What is a prokaryote?
Prokaryotes do not have a nucleus or membrane-bound organelles.
What is a pathogen?
Pathogens are disease-causing organisms and can be fungi, bacteria, protoctists or viruses.
What are the four different types of pathogen?
Virus, bacteria, fungi, protists
What is a specialised cell?
Specialised cells are those which have developed certain characteristics in order to perform particular functions.