Section 2: Organisation And Maintenance Of The Organism Flashcards
Describe the structure of plant cell
Have cellulose wall
Permanent shape determined by the cell wall
Chloroplasts present in some cells
Large permanent vacuole containing cell sao
Nucleus at the side of the cell
What are living organisms made of?
Cells
Describe the structure of animal cell
No cellulose wall Shapes vary as there is no cell wall No chloroplasts Small vacuole, do not contain cell sao Nucleus found anywhere within the cell
Function of cell membrane
Forms a barrier between the cell and its surroundings
Keeps contents of cell inside
Allow simple substances to enter and leave
Controls movement of other substances into and out
Partially permeable
Function of chloroplast
Photosynthesis
Stores starch
Function of nucleus
Controls all activities in the cell
Controls ho cell develop
Function of cytoplasm
Place where chemical reactions take place
Eg. Respiration and making proteins for the cell
Function of cell wall
Stops cells from bursting when they fill with water
Gives shape to cells
Fully permeable
Function of sap vacuole
Full of water to maintain shape and firmness of cell
Stores salts and sugars
Describes ciliated cells
Found in the the air passages in the lungs
Have cilia on their surfaces
Cilia beat back and forth to create a current in the fluid next to the cell surfaces
Move the mucus that traps dust and pathogens up the nose and throat
Describe root hair cell
Function: absorb water and ions from the soil
Have elongated shape and long extension for more surface area
Describe xylem vessel
Cylindrical and empty
Arranged into columns like pipe
The cell walls are thickened with bands or spirals of cellulose and a waterproof material called lignin
This cell allow water and ions to move from the roots to the rest of the plant and support the stem and leaves
No cytoplasm so water passes freely
describe muscle cells
Make up fibre that are able to shorten or contract
When contract they move bones at joints
Function: contract to get structure closer together
Describe red blood cell
Contain the protein hemoglobin that carries oxygen
Shaped like flattened disc
This shape provides a large surface area which makes for efficient absorption of oxygen
No nucleus
Biconcave shape
Define tissue
Group of cells with similar structures, working together to perform specific functions
Define organ
A structure made up a group of tissues, working together to perform specific functions
Define organs system
A group of organs with related functions, working together to perform body functions
Define cell
The smallest part of a living structures that can operate as an independent unit
How to calculate size of specimen
Actual size= image size: magnification
Define diffusion
Net movement of molecules from a region of their higher concentration to a eg ion of their lower concentration down a concentration gradient, as a result of their random movement
What is passive movement?
When cells do not need to use energy to move the molecules
Define active transport
Movement of ions in or out of a cell through the cell membrane, from a region of their lower concentration to region of their higher concentration against a concentration gradient , using energy released during respiration
Define osmosis
Diffusion of water molecules from a region of their higher concentration (dilute) to a region of their lower concentration (concentrated), through a partly permeable membrane
What happen if plant cells are placed into a concentrated sugar solution?
Water passes out by osmosis
These cells are no longer firm - become flaccid
As the vacuole shrinks, the cell membrane moves away from the cell wall
The cell is now plasmolysed
What happen when animal cells is put in distiller water
Water passes into the cell by osmosis
Animal cells have no cell wall to stop them swelling so they burst
What happen when animal cells is put into a concentrated salt solution
They shrink as water passes out of the cells by osmosis
What is water potential gradient
The ability of water to move by osmosis which influenced by how much water is available
What is catalyst?
A substance that speeds up a chemical reaction and is not changed by the reaction
What is enzymes?
Proteins that function as biological catalyst
4 important properties of enzymes
They are all proteins
Each enzyme catalysts one reaction
They can be used again and again
They are influenced by temperature and ph
What is substrate?
Substances that enzymes work on
What is active site?
The reaction takes place on part of the surface of the enzyme
Describe the lock and key model
Only a substrate molecule with a shape that fits into the active sit will take part in the reaction catalyze by this enzymes Other substrate= wrong shape -> don't take part in reaction The substrate (key) must have a shape that fits exactly into the active site ( key hole) of the enzyme (lock)
What is optimum temperature
The temperature at which the maximum rate of reaction occurs
Effect of high temperature on enzymes
High temperature -> greater kinetic energy -> move around more quickly -> mor chances of colliding -> the substrate bind to the active site and the reaction take place in less time
When do enzymes denature?
At higher temperature than optimum temperature, the bonds holding the enzyme molecule together start to break down
The active site change shape and substrate no longer fit and the enzyme can no longer catalyze the reaction
Effect of ph on enzymes
The enzymes can denature if the ph is too low or too high
Enzymes have an optimum pH too
What is complex carbohydrate
Form by joining 3 or more simple sugar molecules together by chemical bond
They are insoluble and not sweet
Eg. Starch and glycogen
What elements make up carbohydrates?
Carbon
Hydrogen
Oxygen
What elements make up protein ?
Carbon Hydrogen Oxygen Nitrogen Some have Sulfur
What is protein?
A long chain molecules make up of smaller molecules called amino acids
Each individual amino acid joins the chain by a chemical bond called a peptide bonds
What elements make up fat
Carbon
Hydrogen
Oxygen
What molecules make up fat?
1 molecule oh glycerol and attached to this are 3 fatty acids
Use for energy storage and thermal insulation in body
How do we test for starch?
Put 2-3 drops of iodine solution (yellow/light brown)
✅ solution turns blue-black
❌ remains the original color
How do we test for protein?
5-6 drops of biuret solution
✅ purple/violet or lilac
❌ remains blue
How do we test for fats?
Add ethanol
✅ white emulsion which is cloudy white/ milky color
❌ nothing happen
How do we test for reducing sugar
Add a few drops of benedict’s solution and heat for 2-3 minutes
✅ green: contains little, deep orange: contains a lot
❌stay bright blue color
Source and importance of carbohydrates
Provide a ready source of energy that is easily respired
Sugars are absorbed immediately into the blood and give an immediate source of energy
Source: rice, potatoes, bread, sugar
Source and importance of fat
Long term energy store
Store under the skin and around the heart and kidney
When we are short of energy our body uses fat
Good thermal insulator and cut down heat loss
Building material
Buoyancy to marine animal
Source: butter, cheese, nut
Source and importance of protein
Make new cells for grow and develop and repair
For energy
Source: meat, fish, milk
Source and importance of vitamin C
Tissue repair
Resistance to disease
Source: oranges, lemons, pineapple
Production of fibre
Source and importance of vitamin D
Absorption of calcium
Strengthens bones and teeth
Source: fish oil, milk, butter
Source and importance of calcium
Strengthen bones and teeth
Source: green vegetables, milk, fish
Source and importance of iron
Used in formation of hemoglobin in red blood cells for transport of oxygen
Source: meat, eggs, liver
Source and importance of fibre
Made up of cellulose
Provides bulk for fences, helps peristalsis
Prevent constipation
Absorbs poisonous wastes from bacteria in gut
Reduces the risk of heart disease and bowel cancer
Source: cereals, cabbage, sweet corn
Source and importance of water
Die in a few day without water Chemical reactions to take place in solutions Water in sweat cool us down Solvent for transport Source: drinks, food
Deficiency symptoms of vitamin C
Scurvy - bleeding gum
Pale skin
Sunken eyes
Deficiency symptoms of vitamin D
Rickets (legs bow outward)
Soft bones
Deficiency symptoms of calcium
Rickets, weak and brittle bones and teeth, muscle weakness and cramps
Deficiency symptoms of iron
Tiredness
Lack of energy - anaemia
Define photosynthesis
Fundamental process by which plants manufacture carbohydrates from raw materials using energy from light
Word equation for photosynthesis
Carbon dioxide + water —(light+chlorophyll)—> glucose + oxygen
Balanced equation for photosynthesis
6CO2 + 6H2O —light +chlorophyll—> C6H2O6 + 6O2
Describe the intake of water
Water enters through root hair cells
Water goes into roots by osmosis
Water transport through the root to the rest of the plant and is transported up by xylem tube
Describe the intake of carbon dioxide
Leaves are adapted for photosynthesis by having a large surface area, and contain stomata to allow carbon dioxide to diffuse into the leave
Function of chlorophyll
Trap slight energy and converts it into chemical energy for the formation of carbohydrates and their subsequent storage
Define limiting factor
Something present in the environment in such short supply that it restricts life process
3 factors that limit the speed of Photosynthesis
Light intensity
Carbon dioxide concentration
Temperature
describe one way to increase the concentration of carbon dioxide
Pump CO2 into glasshouse
Burn butane or natural gas
What is optimum temperature?
The point when maximum rate of photosynthesis occurs
Higher temperature -> rate of photosynthesis decease bc the enzymes in the chloroplast denatured
describe leaf structure
A large surface area to absorbs light
Thin shape so gases can diffuse easily
Many chloroplast to absorb light for the reactions that take place in photosynthesis
Have veins to carry water & ions and take sucrose and amino acids away from the leaf
Describe cuticle
Made of wax - water proof -> stop any loss of water
Secreted by cells of the upper epidermis
Describe the upper epidermis
Thin and transparent -> let light through
No chloroplast
Barrier to disease organism to protect the cell below
Describe the palisade mesophyll
Main region for photosynthesis
Close to the top - get a lot of light
Cells are long and packed with chloroplast to trap light energy
Receive co2 fro, air spaces in spongy mesophyll by diffusion
Describe the spongy mesophyll
Cells are irregular shape and loosely packed to create air space
Contain less chloroplast than palisade
Air spaces between cells allow gaseous exchange by diffusion
Lower so get less sunlight
Describe the vascular bundle
The leaf vein, made up of Xylem and phloem
Xylem: water and mineral
Phloem: sugar and amino acid
Water is absorbed from the soil through osmosis
Water moves up the plant due to evaporate at the leave
This is called transpiration
Support the plant
Describe lower epidermis
Acts as a protective layers
Stomata are present to regulate the loss of water vapor
Site of gaseous exchange into and out of the leaf
Stomata
Surrounded by pair of guard cells which control whether the stomata is open or close
Water pass out during transpiration
Co2 diffuse in and O2 diffuse out during photosynthesis - gas exchange
The important of nitrate ions
For protein synthesis
Nitrates ion from the soil combine with glucose to form amino acids
Amino acids bond together to creat protein
Deficiency of nitrate ion?
Poor growth, weak stem,leaves become yellow, lower leaves, and pale green, upper leaves
Importance of magnesium ions for plant
For chlorophyll synthesis
each chlorophyll contains 1 mg atom
Deficiency of magnesium in plant?
Leaves turn yellow from the bottom of the stem upwards and eventually stop photosynthesis
Uses of nitrogen fertilizer for plant?
Fertilizer replace the missing nutrients
Helps grow faster, increase in size and become greener, healthier, increase crop yield
Provide nitrogen in the form of nitrate ions, or ammonium ions needed for protein synthesis
Danger of overusing nitrogen fertilizer
Eutrophication - nitrogen leaches out of soil and enter a nearby river (cause by rain). Create a layer of green algae on the surface -> lack of light -> Aqua plant can’t photosynthesis -> plant die. Decompose multiply and respite using O2 -> death of Aqua animal from lack of O2
