Biology topics 1 and 2 Flashcards
State the seven characteristics of life.
M.R.S.G.R.E.N: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.
What is movement?
A change in position/place.
What is sensitivity?
The ability to detect (sense) and respond to changes in the environment + changes in the body.
What is respiration?
A series of chemical reactions inside organelles called mitochondria which break down nutrient molecules to release energy.
What is growth?
A permanent increase in size of an organism.
What is reproduction?
Producing offspring by fertilization or cell cloning.
What is excretion?
The removal of toxic/waste substances from the body. Also includes excess, more than the body needs.
What is nutrition?
Necessary materials required in the body for growth, development and repair.
Give an example of nutrition needed by plants and nutrition needed by humans.
Plants: Light, CO2, water, iron, magnesium
Animals: Carbohydrates, Proteins, iron, sodium, water.
Give an example of a substance which is excreted from the human body.
CO2
State the structure of an animal cell.
Nucleus, Mitochondria, Cytoplasm, Cell membrane, Ribosomes, Endoplasmic Reticulum.
State the structure of a plant cell.
Nucleus, Mitochondria, Cytoplasm, Cell membrane, Ribosomes, Endoplasmic Reticulum, Vacuole, Chloroplasts, Cell wall.
What is the function of the cell wall?
The cell wall is made from cellulose, gives the cell support, defines shape, prevents bursting.
What is the function of the vacuole?
Contains cell sap, used for storage of materials + support shape of cell. Not enough Cell sap, plant may wilt.
What is the function of the chloroplasts?
Contain green pigment called chlorophyll which absorbs light energy for photosynthesis.
What is the function of the nucleus?
Contains genetic material in the chromosomes. Controls how cell grows, works + cell division.
What is the function of the ribosomes?
Joins amino acids together to make polypeptides.
What is the function of the Endoplasmic Reticulum?
Fold the chains made by the ribosomes to build proteins.
What are specialized cells?
Cells which have special features, allowing them to carry out their jobs.
Give examples of specialized cells.
Palisade mesophyll cell , Red blood cell, Ciliated cell, Sperm and Egg cells, Root hair cell.
How are Palisade mesophyll cells specialized?
- Lots of chloroplasts - more photosynthesis
- Large vacuole - push chloroplasts closer to edge.
- Cylindrical shape - compact
How are Red blood cells specialized?
Biconcave shape - Larger surface area
No nucleus - more haemoglobin to bind to more oxygen
How are Root hair cells specialized?
Large protrusion - larger surface area
No chloroplasts - UNDERGROUND!
Lots of mitichondria - more energy to absorb more minerals
Large vacuole
How are Ciliated cells specialized?
Goblet cells - Produce mucus which traps foreign substances.
Hairs called cilia which sweep mucus out.
Lots of mitochondria - more energy to move cilia.
How are Sperm cells specialized?
Lots of mitochondria - move flagellum so it can swim more quickly.
Acrosomes - make hole in jelly of Egg cell to get through for fertilization.
How are Egg cells specialized?
Cytoplasm - provides nourishment for for the embryo which makes the placenta.
Jelly coating - solidifies after fertilization to prevent other sperm from fertilizing.
Equation for working out magnification.
Actual size = Image size/Magnification.
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration. Down a concentration gradient)
How does Temperature affect diffusion?
Increase in temp = more kinetic energy - particles will move more quickly
Therefore rate increases.
How does Distance affect diffusion?
Shorter distances = Less area to cover
Therefore rate increases.
How does Concentration affect diffusion?
Larger contrast in concentration = Less particles blocking the way.
Therefore rate increases.
How does surface area affect diffusion?
Increase in surface area = increase in the amount of fluid diffusing at once.
Therefore rate increases.
What is osmosis?
The net movement of molecules from a more dilute solution(high water potential) to a more concentrated solution(low water potential) through a partially permeable membrane.
Osmosis in animal cells.
Pure water = Lyse - cell splits
Isotonic water = Crenate - Cell deflates.
Osmosis in plant cells.
Pure water = Turgid - Swollen
Isotonic water = Flaccid - not hard, membrane is not pressed tightly against the cell wall.
Plasmolysed - cytoplasm is pulled away from cell wall.
What happen to the cells in a potato if they are left in a sugary water?
The cells become Plasmolysed
What happen to the cells in a potato if they are left in distilled water?
They become Turgid.
