homeostasis and cells Flashcards
major systems maintaining health and optimal homeostasis
nervous and endocrine system
define homeostasis
homeostasis monitors the bodies environment for changes and signals mechanisms to prevent disturbance and maintain optimum conditions
what is the importance of maintaining consistency of the internal environemnts
failure to compensate for external changes can cause illness or disease
what is negative feedback
the original condition is removed/becomes switched off by the response
what is feedforward control
additional receptors are used to anticipate change and activate response before initial disturbance
how is water split in the body
2/3 ICL
1/3 ECL
barrier between plasma and interstitial fluid
blood vessel capillary wall which is permeable to everything but plasma protein and blood cells
barrier between interstitial fluid and intracellular fluid
cell membrane which has selective permeability
what is dilution principle
c=m/v
how could you find plasma fluid volume
evans blue or l125 radioactive albumin attach to plasma proteins
how would you find extracellular volume
requires something that freely crosses capillary walls but not cell membranes e.g inulin, Cl or Na
how would you find total body water
no barrier for water in the body so loading dose of deuterated water is used and volume is calculated by:
ISF= ECP-PV , ICF = TBW-ECF
what are the structures present in all cell types
- cytoplasm
- ribosome
- cell (plasma) membrane
role of the nucleus
contains DNA and are sites of rRNA synthesis and ribosomal assembly
role of the endoplasmic reticulum
RER (ribosomes attached, modifies proteins) or SER (no ribosomes, lipid and steroid hormone production)
role of golgi apparatus
packages up proteins in preparation for transport out of the cell
role of ribosome
site of protein synthesis
role of lysosome
bound vesicles containing enzymes, responsible for the digestion of biological materials
role of peroxisome
bound vesicles containing enzymes, responsible for degrading long chain fatty acids and foreign toxic molecules
role of mitochondria
site of oxidative phosphorylation
role of flagella
enables movement
role of cillium
move water relative to the cell in a regular movement of the cilia
describe the structure of the eukaryotic plasma membrane
phospholipid bilayer = double layer of lipid with attached phosphate groups
describe the function of the eukaryotic plasma membrane
selectively permeable via protein receptors
what are stem cells
cells that can differentiate into may (multipotent) or any (pluripotent) cell types of the body
describe stem cell differentiation
undifferentiated stem cells divide and give rise to daughter cells which are genetically identical
what is apoptosis
- controlled programmed cell death
- normal process essential for normal function
what is necrosis
- untimely/unplanned death of cells in response to injury or infection
- not a normal cell process
4 organic elements - biomolecules
H
C
N
O
7 large elements - biomolecules
Na
Mg
K
Ca
P
S
Cl
what is -NH2
amino group
H
-N
H
what is COOH
carboxyl acid
= O
-C
OH
what is OH
hydroxyl group
-O-H
what is H2PO4
phosphate
OH
-O-P=O
OH
what is a redox reaction example
NADH(reducing agent, becomes oxidised) and NAD+ (oxidising agent which becomes reduced
what is making and breaking c-c bonds reaction example
glycolysis (breaking) and gluconeogenisis (making)
what is an internal rearrangements reaction example
glucose 6-phosphate to fructose 6-phosphate (glycolysis)
what is a group transfers reaction example
phosphoryl group transferred from ATP to fructose 1,6-biphosphate (glycolysis)
what is a condensation reaction example
2 smaller molecules combining to form a larger molecule, releasing water
what is a hydrolysis reaction example
breaking a large molecule into smaller units using water
structure of carbohydrates
glucose polymers in open chain or ring form with end monomer: reducing end - aldehyde
structure of proteins
long chains of amino acids formed by condensation. have Amino end and carboxyl end
structure of nucleic acids
in the structure of RNA or DNA made up of a base, phosphate group and sugar
structure of lipids
repeating units of FA’s which can be saturated (single bonds), mono-unsaturated (one double bond) or poly-saturated (more than one double bond)
define hydrophobic
molecules that do not dissolve in water
define hydrophilic
molecules that dissolve in water
define amphipathic
contain both hydrophobic and hydrophilic parts
examples of hydrophilic substances
- sugars
- alcohols
- aldehydes
- ketones
examples of hydrophobic substances
- fat soluble vitamins
- lipids
- oxygen
examples of amphipathic substances
cholesterol
describe a liposome
multiple phospholipids in a lipid bilayer with a hollow core
describe a micelle
single layer of phospholipids with no core
describe a chylomicron
like liposome but with a protein embedded shell
what is meant by a buffer
solutions that resist changes in pH, weak acids and bases have the ability to only partially dissociate, giving them the ability to act as buffers
define metabolism
chemical processes in a living organism by which food is used for tissue growth or energy production
is anabolism endergonic or exergonic
endergonic
is catabolism endergonic or exergonic
exergonic
describe the relationship between catabolic and anabolic processes
free energy flows between catabolic processes and anabolic processes allowing them to occur
what is the 1st law of energy changes
“energy can be converted from one form to another but the total energy of the universe remains the same’
what is the 2nd law of energy changes
“all energy transformations ultimately lead to more disorder in the universe”
