Cells Ch1 Flashcards
Properties of cell membrane.
- must be small to work efficiently
- has a high SA:V ratio
- controls movement in and out of cell.
Plasma membrane
Phospholipid bilayer surrounding the cell.
Describe phospholipids and their polarity.
A phosphate-and-glycerol head with fatty acid(s) tail. Head is polar or hydrophilic, tail is non polar or hydrophobic.
Fluid mosaic theory
Singer and Nicholson 1972. Plasma membrane is a fluid combination of phospholipids, cholesterol and proteins.
Intrinsic proteins
Proteins spanning the entire bilayer, reaches inside of cell, eg channel proteins
Extrinsic proteins
Proteins on surface of cell, eg recognition (marker) proteins.
State types of proteins in cell.
Recognition, channel and receptor proteins.
Receptor proteins.
Recognises and binds specific molecules outside the cell, eg hormones.
Recognition proteins
Sticks out from plasma membrane and helps cells to identify each other and foreign bodies.
Channel proteins
Assists facilitated diffusion of molecules like glucose.
Diffusion
Net movement of substances from high concentration areas to low concentration areas. No energy required.
Passive diffusion
Occurs unaided. Movement across cell bilayer.
Facilitated diffusion
Aided movement across cell via channel protein.
Cell wall.
Surrounds membrane a of plant cells, giving rigidity and structure. Made of cellulose.
Active transport
Movement against concentration gradient, using energy from respiration. ATP gets it through as carrier, leaves as ADP.
Eukaryotic cells
Cells with membrane-bound organelles.
Prokaryotic cells
Cells lacking membrane-bound organelles.
Heterotrophic, with example.
Depends on outside sources for energy. Eg, all carnivores, herbivores, omnivores.
Autotrophic, with example.
Makes its own energy, eg green plants via photosynthesis.
Photosynthetic
Makes energy by converting sunlight, water and CO2 into oxygen and ATP.
Chemosynthetic
Conversion of carbon molecules into energy using inorganic molecules (eg, hydrogen gas) as an energy source instead of sunlight.
Osmosis
Net movement of liquids from areas of low concentration of solutes to areas of high concentration of solutes. No energy required.
Hydrophilic
Water loving, dissolves in water.
Hydrophobic
Water hating, doesn’t dissolve in water.
Hypertonic
Solution with lower concentration of solutes than outside environment, so water leaves the cell.
Hypotonic
Solution with higher concentration of solutes than outside environment, so water enters the cell.
Isotonic
Solution outside cell = solution inside cell. No change.
Extreme effects on spectrum of tonicity.
Hypotonic: the cell lyses in animal cells, becomes turgid in plant cells.
Hypertonic: the cell shrivels in animal cells, undergoes plasmolysis in plant cells.
Endocytosis
Bulk transport of substances into the cell.
Exocytosis
Bulk transport of substance out of the cell.
Phagocytosis
Solids transported inside cell
Pinocytosis
Liquids transported inside cell.
Some properties of skin
- regulates temperature
- regulates water
- forms a protective barrier
- stops stuff falling out
Nucleus
Control centre of cell; where DNA is found; has a membrane.
Mitochondria
Produces all the cell’s energy.
Golgi complex
Packages substances in membrane-bound sacs or vesicles to leave cell. Prominent in cells that shift protein out of cell.
Ribosomes
Where proteins are made. Are floating freely in cell, or attached to ER. Composed of protein and RNA.
Lysosomes
Digestive organelles of the cell, also responsible for programmed cell death (apoptosis).
