Unit 1 - Cell biology Flashcards
What is the type of cell division that makes animals and plants grow called?
Mitosis
What can mitosis replace?
Old and damaged cells
What is the process of Mitosis?
1) Chromosomes replicate becoming pairs of chromatids.
2) Chromosomes start to become visible
3) Spindle fibres form and chromosomes move to the equator of the cell
4) Chromatids are pulled to opposite ends of the cell
5) The nuclear membrane forms
6) The cytoplasm divides and two daughter cells are formed
What is a tissue?
A group of the same cells working together specialised to do a job
What is an organ?
A group of the same tissues working together specialised to do a job
What is an organ/body system?
When 2 or more organs are working together
What are types of organ systems?
Digestive, Nervous Circulatory, Respiratory, reproductive.
What makes up the central nervous system?
Brain and spine
What are the three main types of neurons?
Sensory, Inter and Motor
What doe the sensory neuron do?
Takes stimuli info from the receptors to the CNS
What doe the Inter neuron do?
Operate within the CNS, which processes info from the senses that require a response
What does the Motor neuron do?
Enables a response to occur at an effector
What is the order in the reflex arc?
Stimulus -> Receptors/Sense organ e.g. eyes, ears, skin -> Sensory Neuron -> Inter Neuron -> Motor Neuron -> Effector e.g. muscle and glands -> Response
What are synapse and what do they do?
A synapse is a gap between neurons. Chemical transmitter substances called neurotransmitters are release from tiny sacs at the end of the neuron across the synapse to make an electrical impulse in the next neuron which carries the message along the neurons. (They carry chemical messages between neurons)
What does the cerebrum control?
Learning, memory, imagination, consciousness, thoughts and intelligence.
What does the cerebellum control?
Balance and muscle coordination.
What does the medulla control?
Breathing rate, heart beat and peristalsis.
What happens if the blood glucose concentration in the blood is too low?
Cells cannot no make ATP for energy.
Why are only some tissues affected by a hormone (chemical) message?
A target tissue has cells with complementary receptor
proteins for specific hormones, so only the tissue which is specific to that hormone will be affected.
What is the function of the Petals?
Attract insects
What is the function of the Anther?
Makes pollen
What is the function of the Stigma?
Catches pollen grains
What is the function of the Style?
Pollen tube grows down through this
What is the function of the Ovary?
Contains ovules
What is the function of the Ovule?
Turns into seeds when they fuse with pollen
What is the function of the nectarry?
Produces nectar (sugar) to attract insects
What is continuous characteristics controlled by?
Many genes which is also called polygenic inheritance
What is discrete characteristics controlled by?
one single gene
What are different forms of genes called?
alleles
What is the phenotype?
The physical characteristic which is shown?
What is the genotype?
The alleles an organism has/carries for a particular characteristic
What are examples of homozygous alleles of a gene?
BB/bb
What are examples of hetrozygous alleles of a gene?
Bb
What does the xylem transport and what are it’s properties/structure?
Water and minerals, is a non-living tissue that has lignin to provide strength. Xylem cells are lignified to withstand the pressure changes as water moves through the plant.
What does the phloem transport and what are it’s properties/structure?
Vessels transport sugars made in photosynthesis all around the plant. Phloem tissue is made of 2 types of living cell:
- Sieve tubes - have continuous cytoplasm with neighbouring cells with an end plate like a sieve
- Companion cells - have a nucleus to control sieve tube cells
What does a plant have to be able to transport to survive
- Water from roots
- Glucose from photosynthesis
- Minerals from soil
What is the structure and function of the cuticle?
S - Waxy layer at very top of the leaf structure.
F - Protects leaf and waterproofs (prevents evaporation of water).
What is the structure and function of the Epidermis?
S - Close fitting cells just under the cuticle.
F - Protects leaf and is transparent to let light through.
What is the structure and function of the mesophyll spongy/pallisade?
Palisade
S - Rigid with no space, under epidermis but above spongy mesophyll.
F - Major site of photosynthesis.
Spongy
S - Less rigid with more space, under the palisade.
F - Major site of photosynthesis
What is the structure and function of the leaf vein?
S - Circular shaped tubes made up of xylem and phloem.
F - Transport of water, minerals and sugars
What is the structure and function of the Guard cell?
S - Changes shape and at each side of the stomata.
F - Opens and closes stoma pore by changes in turgour.
What is the structure and function of the stomata?
S - pore at the very bottom of the leaf.
F - allows evaporation of water via transportation and gas excchange
When is the stomata open or closed and why+how is this?
Open - during the day for gas exchange for photosynthesis by becoming swollen/turgid which makes them open up.
Closed - during the day to save water by becoming more shrunken/flaccid and closing over.
What leaves and enters the leaf?
Water and oxygen leave the l;leaf and CO2 enters the leaf.
What is transpiration?
The process of water moving through a plant and its evaporation through the stomata into the atmosphere.
What do root hair cells do to aid osmosis?
Increase their surface are to increase water absorption/osmosis.
How does transpiration work?
1) There is a higher water concentration in the soil than in the root hair cell so water moves into the root hair cell by osmosis.
2) The water will then move from cell to cell by osmosis, as once the water enters one cell the next cell will be in a lower water concentration and so on and so on. The water will move from the root hair cell where it is in the highest water concentration to the root cortex cell, to the xylem vessels where it will have the lowest water concentration.
3) Xylem in the root and stem carry water up against gravity as it is sucked up like a straw by heat.
4) Water arrives in leaf vein and moves out to mesophyll cells and most air spaces.
5) The water then moves from the leaf to the atmosphere.
What is the importance of transpiration?
- It carries water for photosynthesis to the cells in leaves
- The water carries essential minerals in solution
- Evaporation from the leaves has a cooling effect
What can affect the rate of transpiration?
Temperature, wind speed, humidity, surface area, light intensity.
How does temperature affect transpiration?
Transpiration is faster in higher temperatures as evaporation and diffusion are faster at higher temperatures.
How does wind effect the rate of transpiration?
Transpiration is faster in windy conditions as water vapour is removed quickly by air movement, speeding up diffusion of more water vapour out of the leaf.
How does humidity effect transpiration?
Transpiration is slower in humid conditions as diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air.
How does surface area effect transpiration?
If the surface area of the root hair cells is decreased it means that the rate of the absorption of water/osmosis decreases so the rate of transpiration will decrease.
How does light intensity effect transpiration?
In bright light transpiration increases as the stomata (openings in the leaf) open wider to allow more carbon dioxide into the leaf for photosynthesis.
What is on the top, the atrium or the ventricle?
The atrium
What is the artery that pumps
blood to the lungs and what side is it on?
The pulmonary artery and is on the right hand side of the heart and is the valve that comes out of the middle of the heart at this side.
What is the artery that pumps
blood around the body and what side is it on?
The Aorta and is on the left hand side of the heart and is the valve that comes out of the middle of the heart at this side.
What vein takes blood from the lungs back into the heart and what side is it on?
The pulmonary vein and is on the left hand side of the heart and is the furthest right on this side.
What vein takes blood from the lungs back into the heart and what side is it on?
Vena Cava and is on the right hand side of the heart and is the furthest left on this side.
What path does blood take around the body?
The body -> Vena Cava -> Right Atrium -> Right Ventricle -> Pulmonary Artery -> Lungs -> Pulmonary Vein -> Left Atrium -> Left Ventricle -> Aorta -> Body
What are the cronorary arteries and where are they?
The cronorary arteries provide oxygen and glucose for respiration to the heart muscle cells. These arteries branch off from the aorta.
What causes heart disease?
Blocked cronorary arteries mean that blood cannot get to the heart muscle cells to provide oxygen and glucose for the heart muscle cells.
What are properties and functions of the Arteries?
Arteries have thick, muscular walls (for the high pressure of blood) , a narrow central channel and carry blood under high pressure away from the heart. This keeps it moving In one direction in arteries.
What are properties and functions of Veins?
Veins have thinner walls (as less pressure of blood), a wider channel and the blood is under lower pressure so valves are needed in veins to prevent the back-flow of blood and keep blood moving in one direction.
What are properties and functions of the capillary network?
Capillaries are designed for efficient exchange of substances. They come very close to every body cell so that substances can be exchanged. There are Millions of them creating a dense network gives a large surface area for exchange. Thin walls that are only on cell thick mean that the exchange of substances is very fast.
What is the composition of blood?
In mammals the blood contains plasma, platelets, red blood cells and white blood cells and it transports nutrients, oxygen and carbon dioxide.
What is the plasma in blood?
A yellow fluid that carries cells and nutrients.
What is the red blood cells in blood?
A cell specialised to carry oxygen.
What is the white blood cells in blood?
A cell specialised to fight infection (produces antibodies).
What is the platelets in blood?
Cell fragments that help to clot blood.
What are the properties of red blood cells?
They contain the red pigment haemoglobin, which is the molecule that carries the oxygen. Red blood cells are specialised by being biconcave in shape and having no nucleus, which allows them to transport oxygen efficient lay in the form of oxyhaemoglobin.
What are white blood cells?
Part of the immune system and are involved in destroying pathogens.
What are pathogens?
Disease-causing micro-organisms like bacteria, viruses and fungi.
What is each antibody produced by the the lymphocytes specific to?
A particular pathogen
What do Lymphocytes do?
Produce antibodies which destroy pathogens.
What is the respiratory system?
The gas exchange in lungs
What is the pathway of oxygen in the respiratory system?
Nose and Mouth -> Trachea -> Bronchi -> Bronchioles -> Alveoli
What is the trachea?
The long tube that leads to the bronchus and is made of cartlidge to keep the wind pipe open
What is the bronchi/bronchus?
The tubes that take air from the trachea to the bronchioles and has cartlidge.
What are the Bronchioles?
The thinner tubes that lead off the bronchus into the alveoli
What does the mucus do?
Traps dirt and bacteria from inhaled air
What are the cilia and what do they do?
They are tiny hair-like structures which beat to sweep mucus, dirt, and bacteria up to the mouth to be swallowed where they will be destroyed by stomach acid.
What are features of the aveoli?
They have a large surface area, thin walls that are only one cell thick so gas exchange is quick, extensive blood supply as they are surrounded by capillaries, lined with fluid so oxygen can dissolve and diffuse easier
(All of these make diffusion of gases more efficient/easy.
What is the process of nutrient absorption called?
Peristalisis
What are features of the small intestine that make nutrient absorption more efficient?
They are very long (about 5 metres) and are folded into villi which both increase the surface area allowing maximum absorption
What are fats broken down into?
Fatty acids and glycerol
What are fatty acids and glycerol absorbed by?
The lacteal of the villi
What side of the heart has blood that is deoxygenated?
Right
What side of the heart has blood that is oxygenated?
Left
What arteries and veins are on the right hand side of the heart?
A - Pulmonary artery
V -Vena Cava
What arteries and veins are on the left hand side of the heart?
A -Aorta
V- Pulmonary vein
