Life essentials
Prokaryotes do not have a nucleus
movement of particles from low to high conc
ATP/energy required
Membrane proteins required
Which biological is the mains source of energy?
Carbohydrates
Name the green pigment that absorbs light for photosynthesis.
Chlorophyll.
Which chamber of the heart pumps blood to the body?
Left ventricle
What is the function of ribosomes?
Protein synthesis/making proteins
State 2 factors that increases the rate of diffusion.
HIGH temperature
LARGE SA:V
SHORT Diffusion distance
STEEP/LARGE Conc. gradient
What test can you use to test for the presence of enzymes and what should you see?
Biuret
Blue --> Purple
What is the defintion of transpiration?
Evaporation of water into water vapour from the mesophyll cells
Diffusion of water vapour out of of the stomata
What is the balanced chemical equation for anaerobic respiration in muscle cells?
C6H12O6 --> 2C3H6O3
A student places a plant cell in distilled water.
Is the solution hypertonic, hypotonic, or isotonic? What happens to the plant cell? (4 marks, use keywords)
Hypotonic (1)
Osmosis (1)
Water enters plant cell (1)
Plant cell becomes turgid (1)
Increased turgor pressure (1)
What are some adaptations of the root hair cell?
Root hair = large SA
Many mitochondria = energy for active transport of mineral ions
No chloroplasts = underground
Where is bile produced? What are its 2 roles?
Liver (1)
Role 1= Fat emulsification (mechanical digestion) to increase SA for lipase to work
Role 2= Alkali to help neutralise pH from stomach acid
Xylem has lignin
Xylem cells have no organelles/hollow
Phloem require a lot of mitochondria
Xylem has no transverse cells walls/Phloem has sieve plates
Explain some adaptations of the vein. (3)
Valves to prevent blood flow
Wide lumen to prevent resistance
Positioned between muscles to help pump blood towards the heart
A microscope image shows a cell measuring 60 mm. The actual size of the cell is 60 microns.
Calculate the magnification.
60 microns = 0.06 mm
Magnification = image size ÷ actual size
= 60 ÷ 0.06
= 1000×
How is the alveoli adapted for gas exchange? (4 marks)
Moist
large SA
Walls are one-cell thick
rich blood supply
What happens to lipase in the stomach? Explain. (4 marks)
Lipase gets denatured. (1)
HCl in stomach (1), pH is too low for lipase to function (1)
Change in shape of active site (1), no longer complementary to substrate (1)
Explain why transpiration increases on a windy day
Lower humidity per second near the leaf surface
Steep concentration gradient generated
Increased rate of diffusion of water vapour out
How does vaccination help with immunity? (5 marks)
Introduces pathogen (1)
With antigen (1)
Lymphocites (1) make complementary (1) antibodies (1)
Secondary immune response in case of infection (1)
Faster production of more antibodies (1)
Herd immunity (1)
Explain why diffusion alone is insufficient to meet the needs of a large multicellular organism. What do large organisms have instead? (3 marks)
Large organisms have a low surface area to volume ratio (1) and longer diffusion distances (1), making diffusion too slow.
Large organisms have transport systems such as the circulatory system in animals or the vascular bundle in plants. (1)
Blood concentration increases
Water from cells leave by osmosis
Cells lose their shape/shrivel
Cannot perform their function
Explain what happens to a grain of rice that you have eaten. Start from the mouth until it is used by the cells. (6 marks)
Mouth - mechanical digestion (chewed) and chemical digestion (starch --> maltose with the help of amylase)
Swallowed into Oesophagus
Now in stomach, it is churned, passes through acid, and then goes to duodenum
In the duodenum, it is digested with the help of maltase which was secreted by the epithelial lining of the duodenum (maltose --> glucose)
Glucose is then absorbed into the blood capillaries inside the villi in the ileum and is transported to the liver through the hepatic portal vein
From here it is assimilated into the blood and used by cells for respiration to release energy
Waxy cuticle/upper epidermis
Palisade mesophyll
Vascular bundle (xylem/phloem)
Spongy mesophyll
Lower epidermis
Stomata
Guard cells
Explain how increased smoking can increase the risk of heart attack. (6 marks)
Nicotine - vasoconstriction
Carbon monoxide = reduces oxygen carrying capacity of heart
Heart compensates by pumping harder
Increased blood pressure
Increased risk of blood clots within coronary artery
Less volume of blood flows to heart muscles
Lower conc of glucose and oxygen
Lower respiration
Lower energy
heart muscles die