cells part one

Question 1

whats cell (plasma membrane)

Answer 1

forms the external boundary of the cell. it separates cell from its external enviroment. regulates the transportation of substances into or out of the cell eg oxygen or glucose. it is selectively permamable

Question 2

whats cytoplasm

Answer 2

consists of gel like substance in which numerous organelles are suspended. the organelles are small and varied structures of the body which provide structure and carry out various functions of the cell.

Question 3

whats the nucleus

Answer 3

control centre of the cell. contained within its own membrane. within it is the nucleic acid DNA which contains the genetic informnation of the individual. DNA is responsible for directing protein synthesis and regulating the cell life cycle and function.

Question 4

cell membrane fluids

Answer 4

flexible structure that defines the extent of the cell by separating two fluid compartments. Intracelluar fluid which is inside the cell and extracellular fluid which is outside the cell

Question 5

what does cell membrane do

Answer 5

its selectivly permable membrane which regulates the transportation of substances into and out of the cell between the ICF and ECF.

Question 6

what is cell membrane made up of

Answer 6

Phospholipid bilayer - double layer phospholipids, each lipid is composed of a hydrophilic phosphate head and two hydrophobic lipid tails
Proteins - numerous types of proteins are found, they funtion enzyme activity, cell to cell recognition, attachment to cytoskeleton, receptors for signal transduction and transportation of substances into and out of body
carbohydrates- some surface carbs form antigens on the cells surface which identify that cell as self to bodys immune cells
glycolipids - combined lipid and carbo
glycoprotein - combined protein and carbo
cholesterols - stabilize the membrane while allowing mobility and flexibility.

Question 7

what fluids make up body

Answer 7

water accounts for 55-60% of body fluids. it is contained within two compartments. ICF and ECF. intracellular makes up majority of total body water fluids at 66%. ECF makes up the remaining outisde the cell at 33%. it is futher split up into plasma which takes up 8% (1/5) and interstitial fluid which takes up 25% (4/5)

Question 8

whats is most common electrolyte in ICf and ECF

Answer 8

potassium in ICF and sodium in ECF

Question 9

whats diffusion

Answer 9

diffuion of solutes across the cell membrane is driven by that solutes concentration gradient the difference in concentration of the solute between the ICF and the ECF when a solute diffuse it will always move down the concentration gradient. from high to low conc.

Question 10

describe diffusion via protein channel

Answer 10

sodium ions move through a sodium cheannel down their concentration gradient.

Question 11

describe diffusion via carrier protein

Answer 11

amino acids movr into a cell via a carrier protein beacuse there is less amino acids inside the cell

Question 12

describe simple diffusion

Answer 12

carbon dioxide molecules move out of the cell through the phospholipid bilayer

Question 13

whats osmosis

Answer 13

the diffusion of water. can occur during simple diddusion but mainly through special protein carriers called aquaporins. osmosis is based on the osmolarity between the icf and eco. the osmolarity should be equal, if not water will move between them this is called a fluid shift. water always moves from low osmolarity to high

Question 14

whats a fluid shift

Answer 14

if water and or electrolyte intake and output are not balanced the ECF osmolarity changes and to composate there will be a fluid shift. fuild shift alters volume and size of the cells which can lead to celluar disfunction if these chnages are serve or sustained.

Question 15

whats passive cell transport

Answer 15

occurs without the use of celluar energy and occurs via osmosis, diffusion or filtration

Question 16

whats filtration

Answer 16

occurs acorss specially designed filtration barriers. its the movment of water and permeable substances across cell membrane due to the force of pressure. high pressure in one fluid compartment can push substances across the membrane into an area of low pressure.

Question 17

whats active cell transport

Answer 17

requires the use of ATP to move substances cross the cell membrane against their concentration. from low to high conc

Question 18

how does active transport work

Answer 18

solute transporter pumps are proteins that actively move dolutes across the cell membrane against their conc gradients. there are different types of pumps depending on the number of solutes being moved and their direction of movement. one of the most important is odium potassium pump, it pushes sodium out of cells and potassium into cells which is esstienal for healthy cell survival.

Question 19

whats vesicular transport

Answer 19

describes the transportation of fluids containing large particles (macromolecules) across the plasma membrane. small membranous sacs called vesicles composed if phospholipids surround the fluid and the cell to be transported and release their contents on the other side of the membrane

Question 20

exocytosis

Answer 20

vesicle formed within the cell bind to and fuse with the cell membrane then release their contents outside the cell

Question 21

endocytosis

Answer 21

substances from the exterior of the cell are wrapped in a small bit of the phospholipids od the plasma membrane which pinches off and moves into the cell. a particular form of endocytosis includes phagocytosis which is the process by which certain body cells engulfs and then destroy microorganisms or large particles

Question 22

most important electrolytes for body fluid balance and hormones that regulate them

Answer 22

sodium - aldosterone - stimulates kidney to retain sodium (eg decrease urine loss)
potassium - aldosterone - stimulates kidney to excrete potassium (eg increase urine loss)
calcium - parathyriod hormone - stimulates kidneys to retian calcium (eg decrease urine loss) stimulates increase intestinal absorption of calcium from diet and stimulates release of stored calcium form bones into blood. This all ensures the osmolarity between ICF and ECF is maintained and fluid shiftd avoided

Question 23

water balance mechanisms

Answer 23

thrist mechanism - triggered when osmolarity of the plasma increases to encourage water consumption to decrease it. also triggered by signifigant losses in plasma volume as water consumption will increase blood volume. is controlled by hypothalamus
Anti diuretic hormone (ADH) - hormone that stimulates kidneys to retain water (eg decrease urine loss) while there is minimum amount of water that must be exerted by the kidneys each dayto ensure removal of certain solutes from the body. ADH can decrease water loss to this minimum to conserve water. ADH is released when osmolarity of plasma increases

Question 24

cytoplasm main parts

Answer 24

cytosol - viscous fluid which suspends the other cytoplasmic contents. composed of mainly water but also proteins and solutes.
organelles - structures or machines in the cell that carry out specific cellular functions
inclusions - chemical substances that are present in some cell types
cytoplasm is everything between membrane and nucleus

Question 25

whats anabolism and catabolism

Answer 25

anabolism - any process which larger molecules or structures are built from smaller ones. these are synthesis or genesis reactions which store energy and heat.
catabolism - any process that breaks down complex structures into smaller molecules. these are degenerative reactions which release energy and heat

Question 26

whats BMR

Answer 26

basal metabolic rate. its the base rate of metabolic reactions (energy outputs) required to maintain only the body most essentail functions. to maintain BMR it will require minimum energy input (nutrition)

Question 27

whats cellular metabolism

Answer 27

involves metabolic reactions taking place within a cell that utilise the nutrients from the diet

Question 28

main components of cellular metabolism

Answer 28

anabolic reactions - facilitate energy storage and structural building/repairing
catabolic reactions - lead to step two and the generation of ATP. this step occurs within cytoplasm of the cells

Question 29

whats cellular respiration

Answer 29

a series of catabolic reactions which generate atp. in most cases oxygen is required for this step and occurs inside the mitochondria of body cells.

Question 30

cellular respiration cycle

Answer 30

pyruvic acid turns to Acetyl COA then to the krebs cycle which is a series of reactions that create 4 reduced co-enzymes. these undergo oxidative phosphorylation and electron transport chain which then creates lots of ATP

Question 31

gluconeogenesis meaning

Answer 31

conversion of fats or proteins into glucose

Question 32

lipolysis meaning

Answer 32

breakdown of triglycerides into glycerol and three fatty acids

Question 33

glycogenesis meaning

Answer 33

formation of glycogen from glucose molecules (glycogen is long chains of glucose molecules for storage)

Question 34

protein synthesis

Answer 34

formation of proteins from amino acids

Question 35

glycolysis meaning

Answer 35

breakdown of glucose into pyruvic acid molecules

Question 36

lipogenesis

Answer 36

formation of triglycerides from glycerol and fatty acids (may be derived from glucose)

Question 37

transamination and deamination

Answer 37

removel of nitrogen/amine group from amino acid to convert it into a keto acid for entry into the Krebs cycle

Question 38

glycogenolysis

Answer 38

breakdown into individual glucose molecules