| cell theory | all organisms are made of cells, which are the basic unit of life and arise from pre-existing cells |
| cell membrane | separates cell contents from outside the cell
encloses cell contents and controls what enters and leaves is |
| cytoplasm | jelly like, watery material
fills space between nucleus and cell membrane
made from cytosol and organelles |
| cytosol | the liquid part of the cytoplasm
where most metabolic reactions occur
controls osmotic pressure inside the cell
dissolved salts and carbohydrates |
| nucleus | largest organelle in the cell
oval/spherical |
| nuclear pores | allow large molecules, such as messenger rna to enter and leave the nucleus |
| nuclear membrane | separates nucleus from cytoplasm
double membrane |
| dna | inside nucleus
contains information that determines type of protein cell can make
controls the structure and function of the cell
nucleolus also plays a part in manufacturing proteins |
| ribosomes | small, spherical
where amino acids are joined to make proteins
can be free in cytoplasm or connected to other organelles |
| endoplasmic reticulum | membranes that form channels in cytoplasm
used for storage, support, synthesis and transport in the cell
rough has ribosomes, smooth doesn't |
| structure and function of the body results from... | the activities of its cells |
| golgi body | flattened, stacked membranes, usually near the nucleus
modifies proteins and packages them for secretion
proteins produced at ribosomes pass through ER to the golgi body
at the edges of the membranes, small sacs of proteins are formed, surrounded by a membrane called vesicles |
| lysomes | formed from golgi body, bound by membrane
digestive enzymes break down large molecules
vesicles that enter the cell and worn out organelles join with lysomes to be broken down |
| mitochondria | double membrane, outside surrounds mitochondrion
inner membrane (cristae) folds inside
where cellular respiration and some chemical reactions occur |
| fcilia and flagella | fine projections that can beat back and forth to move substances/molecules
tiny 'hairs' are cilia, longer ones are flagella
cilia in trachea
flagella are on sperm |
| cytoskeleton | framework of protein fibers that shape cell and assist movement |
| intwo types of cytoskeleton | microtubules-hollow rods, hold/move organelles
microfilaments-move materials around cell/move cell |
| inclusions | chemical substances not part of cell structure, found in cytoplasm
eg. haemoglobin and pigment melanin |
| fluid mosaic model explains what | structure and function of the membrane
(constantly moving and made up of many different molecules |
| cell membrane composed of... | phospholipids, form a bilayer |
| structure of phospholipids | hydrophobic head
2 hydrophilic tails |
| properties of phospholipid bilayer | held together by weak hydrophobic interactions in tails
phospholipids and other materials move within bilayer
fluid, can break and reseperate |
| composition of the bilayer | cholesterol and protein molecules embedded
important for function integrity and stability of membrane |
| functions of the cell membrane | physical barrier-separates cell from surroundings
regulate passage of materials-controls movement of materials entering and leaving
sensitive to changes-first thing affected by changes outside cell
supports cell-internal part of cell membrane is attached to cytoskeleton-connections between other cells membrane, providing whole tissue support |
| simple diffusion | molecules diffuse through the membrane
along concentration gradient
co2, o2, fatty substances, steroids, alcohol |
| osmosis | where solvent moves across a semi permeable membrane to where a solute is in higher quantity
simple diffusion |
| protein channels | water soluble molecules diffuse through channel
large molecules don't fit
facilitated diffusion |
| carrier meditated transport | one end open at a time
specific to one particle
become saturated, proteins can only process a certain amount in a certain time
regulated by hormones |
| facilitated diffusion | along concentration gradient
molecule attaches to a binding site on a specific protein, protein then changes shape to allow molecule to be released on the other side of the membrane
carrier meditated transport |
| active transport | requires atp
against concentration gradient
similar to facilitated diffusion |
| vesicular transport | where droplet or solid enters or leaves cell |
| endocytosis | coming into the cell, membrane folds over and then pinches off
pinocytosis-liquid
phagocytosis-solid |
| exocytosis | out of the cell, fuses with membrane |
| cell inputs | oxygen, nutrients(lipids, amino acids, glucose), minerals, ions, vitamins, water |
| cell outputs | co2, toxic substances, proteins (hormones... |
