biology

Biology

2 major ways that molecules can be moved across a cell membrane
The distinction has to do with whether or not cell energy is used
Passive transport (no energy needed)
Active transport (energy needed)
Passive transport molecules travel down the concentration gradient from high to low
Active transport travel against the concentration gradient from low to high
2 different types of diffusion
Higher concentration of molecules outside the cell than inside the cell
Diffusion molecules travel across the membrane
Simple diffusion molecules travel down their concentration gradient through the membrane but these molecules need to be small and nonpolar
facilitated diffusion go through a channel protein
Osmosis is the movement of water from a less concentrated solution to a more concentrated solution through a semi-permeable membrane
The important thing to remember is that osmosis is the movement of water not the particles dissolved in the water
For example if you split a beaker of water into two halves with a semi-permeable membrane in the middle and added salt to one the water would move from the side of the beaker with no salt until both concentrations are the same
Facilitated diffusion is diffusion that is helped along by a membrane
The difference in the concentration of a substance between two areas is called the concentration gradient the bigger the different the steeper the concentration gradient
Passive transport is a automatic movement
Active transport is not a automatic movement and needs energy to move through and against the concentration gradient

\ TERM 3

A- Adenine
T- Thymine
C- Cytosine
G- Guanine
2 main processes- translation and transcription
Muscle cells are joined together to form a tissue and are a part of an organ.
Multicellular organisms have a hierarchical structure of organizations of cells, tissues,
Stems cells- muscles cells, fat cells, bone cells, blood cells. Sex cells, skin cells
Four basic types of tissues
Epithelial are responsible for protecting surfaces
connective tissue support and bind
Muscle are able to contract
Nervous tissue can detect stimuli and transmit messages