Cell Bio Chapter 3 Flashcards
how many cells in human body
100 trillion
3 main parts of cell
nucleus
plasma membrane
cytoplasm
why does a cell have a plasma membrane? 3 things
protection
communication
transport
what is the plasma membrane made out of?
phospholipids and embedded proteins
what is cytoplasm made of?
jelly like substance made of water, salt and proteins
what is the cytoplasm’s purpose?
hold the organelles
provides a medium for chemical reactions to occur
what is the purpose of the nucleus?
controls growth, reproduction and metabolism
holds the nucleoli, chromosome and chromatin
what is the cell membrane made of?
specifically
phospholipids which have hydrophilic heads (face outward) and hydrophobic tails (face inward)
what are the 3 functions of the proteins embedded in the membrane
channels
gates
receptors
why is the membrane also called the “fluid mosaic”?
because the phospholipids and proteins can move around within the layer
what is the outside of the membrane called?
the lipid bilayer (double layer)
what is the main structure of the lipid bilayer?
heads that are hydrophilic
tails that are hydrophobic
what is cholesterols function within the membrane?
to keep it flexible
what is the function of glycolipids in the membrane?
mainly used for receptors and communication (usually facing outwards)
what to integral proteins do in the membrane?
they are embedded in the membrane and span across the whole thing, providing transport
what do peripheral proteins do in the membrane?
loosely attached to the outside of the membrane, act as receptors and transport substances across the membrane
What are ion channels?
specialized doors that open and close to let specific ions pass through
what is a carrier? (integral)
specialized carrier proteins that move molecules in and out of the cell (nutrition and waste)
What is a receptor? (integral)
essentially an antennae (picking up outside info and relaying it to the inside
somatic meaning?
body
how many chromosomes do human cells have?
46
linker proteins function (integral and peripheral)
connectors that keep structure intact
communication and adhesion between cells
enzyme function (integral and peripheral)
assist in various functions on inside and outside of cell (ex chemical reactions)
cell identity (glycoprotein)
helps cells communicate and interact with each other
What is the liquid bilayer permeable to? (highly permeable to impermeable)
O2, CO2, steroids (highly permeable)
water and urea (moderately permeable)
ions, large uncharged particles such as glucose (impermeable)
concentration gradient meaning
a difference in the concentration of a substance
electrical gradient meaning
a difference in the electrical charge across a membrane
what are the two types of transport across the membrane
active and passive
passive transport meaning
moves substances without the use of energy from the cell
active transport meaning
moves substances across the cell membrane with energy (usually ATP)
what is simple diffusion?
when a substance moves from an area of high concentration to an area of lower concentration until they are evenly distributed
what is facilitated diffusion?
when a substance moves across the membrane with help from special proteins, (but they don’t require energy)
what is osmosis
when water moves across the membrane from a area of low solute to an area with high solute
what is tonicity?
The solute concentration outside the cell is equal to the concentration inside the cell
what are the 3 tonicity states?
describe the states
isotonic - outside the cell has the same amount of solute as inside the cell
hypotonic - outside the cell has less solute than inside the cell (the cell sucks in water and could potentially burst)
hypertonic - the outside of the cell has more solute than inside the cell (this causes water to leave the cell and it could shrink)
describe vesicle transport
vesicle sacs move the substance from one side of the membrane to the other
name the 3 directions of vesicle transport
endocytosis - the substance is moved from outside to the inside of the membrane
exocytosis - the substance is moved from inside to the outside of the cell
transcytosis - the membrane is moved from one side of the cell to the other (within the cell)
what is the cytoskeleton?
a network of protein fibers than form a sort of cage to keep the cells shape (also has roads that allow things to move around)
what is one of 3 things that a cell must do?
remain alive and function well
grow and divide
die
What are:
DNA expression
transcription
translation
(in simple terms)
DNA template
DNA is copied
RNA attaches to a ribosome
what is mitosis?
the action of duplicating the cells contents and making two identical copies
what is meiosis?
reproductive cell division
what is cell diversity?
different cells for different purposes
What do glycoproteins help with?
cell communication
where are phospholipids mainly found in the cell
the lipid bilayer
