b) Antibiotics work by damaging the cell wall of bacteria.
1. Structure of the eye.
2. Functions of the eye structures.
3. Booklet page 9 exercise 3.
5. Booklet page 9 exercise 2: The cornea bends or refracts the light rays for the lens to bend and focus them on the fovea (if there is a bright light, on cones) or throughout the retina (if there is dim light, on rods).
6. VIDEO explaining the pupil reflex.
-stimulus: a bright light. >> receptor: cones >> coordinator: brain >> effector: radial and circular muscles >> effect: circular muscles contract while radium relax >> response: the pupil constricts.
-stimulus: a dim light. >> receptor: rods >> coordinator: brain >> effector: radial and circular muscles >> effect: circular muscles relax while radium contract >> response: the pupil gets dilated.
CIRCULAR MUSCLE vs RADIUM MUSCLE: Antagonistic muscles
7. Booklet page 9 exercise 1c: In the dark room light is focused all over the retina, where the rodes are. Rodes are stimulated the, but rodes are of black and white vision only. So Jasmin seed only shapes, not colours.
8. Animations to learn how the eye focuses on a nearby and a distant object.
9. Booklet page 9 exercise 2b: If a close object is focused, the light rays coming will be diverging so they will need a lot of bending. The cornea will bend them and focus them on the lens and the lens will need to be thick so it bends more. The ciliary muscles contract, the suspensory ligaments go slack and the lens becomes shorter and fatter.
Booklet page 10 exercise 4a: Lens and cornea
10. Booklet page 10 exercise 5:
a. light receptors bring out electrical impulses.
1.a. Key Parts of the Control Center; The Receptors; The neurons and nerve cells;
Sensory Neuron: transmits nerve impulses from receptors to coordinators.
Relay Neuron: Transmits nerve impulses from Sensory Neurons to Motor Neurones.
Motor Neurones: Transmits nerve impulses from the central nervous system (brain & spinal cord) to effector nerve cells.
c. Reflex Action:
Stimulous >> recept cells >> coordinators (CNS) >> effector cells
A synapse is what happens when chemical signals pass from one cell to another. It occurs in the synaptic cleft, which is the tiny gap between the pre-synaptic neuron and the post-synaptic neuron.
Every pre-synaptic neuron has vesicles inside, near the pre-synaptic membrane. Each vesicle contains thousands of neurotransmitters. When the pre-synaptic neuron gets “excited” by an axon potential it’s vesicles diffuse through the cell membrane and release their content into the synaptic cleft.
Following, the tiny receptors of the post-synaptic neuron interact with the neurotransmitters. These ones bind into the receptors and cause an action as result. Likelihood can be increased and the cell becomes activated firing an action potential or it can be decreased.
Finally, the neurotransmitters molecules left in the synaptic gap drift away by diffusion, or go back to the vesicles to be reused by a process called re-uptake, or are broken down by enzymes and component parts go back to the pre-synaptic neuron.
In Biology we are studying the Respiratory System.
Here is a post of Male’s blog that explains very well the topic with some tests and activities! (STUDY FROM HERE)
Comparing the amount of carbon dioxide in inspired and expired air we lead to a:
HYPOTHESIS: The expired air contains more carbon dioxide than the inspired air.
- The cells in our body need energy to: Contract muscles, so we can move; make protein molecules by linking together amino acids into long chains; repair damaged tissues through cell division so we can grow; carry on active transport; transmit nerve impulses, so we can transfer information quickly; to produce heat inside the body, to keep the body temperature constant if the environment is cold.
3. When we run in a race, for example, we need a lot of oxygen in order to release energy to contract our muscles. We keep on running, maybe faster, and we need every time more and more energy. Our heart starts to beat faster because we need energy to reach our blood more quickly since we are constantly losing it. But eventually we can’t breath more quickly than we have been doing. There is when we produce “extra energy” by anaerobic respiration. Glucose is broken down without combinating it with oxygen. This action releases lactic acid and energy. “Oxygen Debt” is this action. When we “borrow” some extra energy without “paying” for it with oxygen. As a consequence of this we have a lot of lactic acid left in our muscles and blood which can be broken down by combinating by aerobic respiration.
4) How does the cholera bacterium cause diarrhoea? The cholera bacteria which lives and breeds in the small intestine produces a toxin that stimulates the cells lining the intestine to secrete chloride ions. Then the ions accumulate in the lumen of the small intestine and increase the concentration of the fluid in the lumen lowering its water potential. When this water potential becomes lower than the one of the blood flowing through the vessels in the wall of the intestine, water moves out of the blood into the lumen of intestine by osmosis. So large quantities of water are lost from the body in the watery faces.