Topic 1-Key Concepts Flashcards
Acrosome
An organelle in the tip of a sperms cell that contains enzymes which digests the egg cell membrane
Active Site
A specific region on an enzyme where the substrate binds and a reaction takes place
Active Transport
The movement of substances from a low concentration to a higher concentration (along a concentration gradient) across a membrane-with energy from respiration
Carbohydrases
Enzymes that break down carbohydrates into simple sugars
Carbohydrates
Large molecules that are synthesised from simple sugars
Cell
The basic building block of all living organisms
Cell membrane
A partially permeable barrier that surround a cell
Cell wall
An outer layer made of cellulose that strengthens plant cells
Chloroplast
An organelle that is the site of photosynthesis
Chromosome
A long, coiled molecule of DNA that carries genetic information in the form of genes
Cilia
Hair-like structures found on ciliated epithelial cells which waft substances across the surface of the tissue in one direction
Ciliated Epithelial Cell
Type of epithelial cell that lines the surfaces of structures (e.g respiratory tract/uterus)
Concentration Gradient
The difference in concentration between two areas
Denaturation
The permanent change in the shape of an enzymes active site that prevents the binding of a substrate (upon exposure to high temps or extremes of pH)
Diffusion
The net spreading out of particles from a high concentration to a lower concentration (down their concentration gradient)
Diploid cell
A cell that contains two copies of each chromosome (full set of chromosomes)
Egg Cell
A specialised female sex cell involved in reproduction
Electron microscope
Type of microscope that uses a beam of electrons which are focused using magnets to produce an image of a specimen.
It has a greater magnification and resolution that a light microscope.
Enzyme
A biological catalyst that increases the rate of reaction in living organisms (without being used up)
Eukaryotic cell
A type of cell found in plants and animals that contain a nucleus
Flagella
A long, hair-like structure found on bacterial cells-used for movement
Hapolid cell
A cell that contains a single copy of each chromosome (half the number of chromosomes)
Light microscopes
A type of microscope that uses a series of lenses to magnify the visible light reflecting off a specimen.
It has a lower magnification and resolution than an electron microscope.
Lipases
Enzymes that break down lipids into fatty acids and glycerol
Lipids
Large molecules that are synthesised from fatty acids and glycerol
Lock & Key Hypothesis
A theory that describes how substrates must be the correct shape to fir the active site of an enzyme
Magnification
The number of times bigger an image appears compared to the original object.
Magnification (Calculation)
Image size = magnification x actual size
Micrometre (um)
Equal to x10^-6
Millimetre
Equal to x10^-3
Mitochondria
An organelle that is the site of respiration
Nanometre
Equal to x10^-9
Nucleus
An organelle found in most eukaryotic cells that contain the genetic material of the cell and controls the activities of the cell
Organelle
A specialised structure found inside a cell
Osmosis
The Diffusion of water molecules from a region of high water concentration to a region of lower water concentration across a partially permeable membrane
Percentage change in mass
Proportion of the mass of a substance that has changed over a set period.
Caculation:
%change in mass=(final mass-initial mass/initial mass) x100
Picometre
Equal x10^-12
Plasmid
Loops of DNA found in the cytoplasm of prokaryotic cells
Prokaryotic Cell
Type of cell found in bacteria that doesn’t contain a nucleus
Proteases
Enzymes that break down proteins into amino acids
Proteins
Large molecules that are synthesised from amino acids
Rate of Reaction
The speed at which reactants are converted into products
Resolution
The smallest distance between two objects that can be distinguished
Ribosomes
Sub-cellular structures that are the site of protein synthesis
Specialised cell
A cell that has a structure which makes it adapted to its function
Specifity
Describes the ability of an enzyme to catalyse only a particular reaction or set of reactions in which a specific substrate fits the active site of the enzyme
Sperm Cell
A specialised male sex cell that is involved in reproduction
Vacuole
An organelle found in plants cells which stores cell SAP and supports the cell
Features of Animal Cells
Cytoplasm, nucleus, cell membrane, mitochondria
Features of Plant Cells
Nucleus, cytoplasm, cell membrane, mitochondria
Cell wall, chloroplasts, vacuole
Features of Bacterial Cells
Cytoplasm, cell membrane, cell wall, chromosomal DNA, plasmids, Falgellum
How do cells become specialised?
By undergoing Differentiation.
A process that involves the cell gaining new Sub-cellular structures to be suited for its roles
(most cells differentiate only once early on in their lives, but some differentiate their whole lives=stem cells)
How are sperm cells specialised/adapted to their function?
They are specialised to carry the males DNA to the egg cell for successful reproduction.
Features:
-streamlined head and long flagellum to aid swimming
-many mitochondria that supply the energy needed for the cell to move
-acrosome that contains digestive enzymes that break down the outer layers of the egg cell membrane
-halpoid nucleus (only 23 chromosomes)
How are egg cells specialised/adapted to their function?
They are specialised to accept a single sperm and develop into an embryo.
Features:
-surrounded by a special cell membrane that only accepts one sperm cell and becomes impermeable following this
-lots of mitochondria to provide an energy source for the developing embryo
-large size and cytoplasm allows for quick, repeated division as the embryo grows
How are Ciliated Epithial Cells adapted to their function?
They are specialised to waft bacteria (trapped by mucus) to the stomach.
Features:
-long, hair-like processes (cilia)
How are Root hair cells specialised/adapted to their function?
Specialised to take up water by osmosis and mineral ions by active transport from the soil (as they’re found in the tips of roots)
Features:
-large surface area=more water can move into the cell
-large permanent vacuole affects the speed of movement of water from the soil to the cell
-mitochondria provide energy from respiration for active transport to take place
How are Xylem cells specialised/adapted to their function?
-upon formation, a chemical (lignin) is deposited that causes the cells to die and become hollow and are re-joined end to end to form a continuous tube
-water and mineral ions cans move through this tube
-lignin is deposited in spirals which help the cells withstand the movement of water
How are Ploem cells specialised/adapted to their function?
Specialised to carry the products of photosynthesis to all parts of the plants
Features:
-when cell walls of each cell structure (sieve plates) break down to allow the move the movement of substances from cell to cell
-energy is supplied by the mitochondria of the companion cells
