Week 1 Cell structure, Thermodynamic Flashcards
Difference between Prokaryotic and Eukaryotic cells
Prokaryotic cell: Bacteria
- Lacks a nuclear membrane - No mitochondria - No membrane-bound organelle
Eukaryotic cell - Human cells
- Multicellular animal and plant - Nucleus with membrane - Membrane-bound organelles
Explain stem cells
stem cells are cells that can differentiate into many (multipotent) or any (pluripotent) cell types of the body
Why are stem cells of interest in medical science?
Now allow stem cells to be used in the treatment of certain diseases including some cancers
Explain cell differentiation
- Cells pass through a series of changes during development
- undifferentiated stem cells divide and give rise to daughter cells.
Differences in GENE EXPRESSION AND LOCAL CELLULAR ENVIRONMENT cause daughter cells to develop into different cell types.
What allows daughter cells to develop into different cell types?
Differences in gene expression and the local cellular environment.
What is apoptosis?
Apoptosis is programmed cell death. This is a normal process - apoptosis and cell proliferation are intimately coupled
What is necrosis?
Necrosis describes the untimely death of cells in response to injury or infection.
This is not a normal process
What is Cell proliferation?
Cell proliferation is the process by which a cell grows and divides to produce two daughter cells.
Describe cancer cells
Cancer cells - Divide without any control
- Fail to coordinate with normal cells
- Fail to differentiate into specialized cells
- Displace and replace the normal cells if not stopped.
Describe the Cell membrane/ Plasma membrane/ plasmalemma
Comprises a double layer of lipids with attached phosphate groups = phospholipid bilayer.
Selective permeability/barrier
proteins embedded in membrane acting as receptors
signalling molecules in the fluid around cells (extracellular fluid)
What is oxidative phosphorylation?
Oxidative phosphorylation
When other ATP producing reactions occurs as a result of the transfer of electrons from NADH, FADH2 or 02 by a series of electron carriers
Describe the nucleus in eukaryotes
The nucleus
Contains DNA, nucleoprotein and some RNA
The nucleus is enclosed in the nuclear membrane
Describe a prokaryotic cell
Prokaryotic cell - Bacteria
Lacks a nuclear membrane
no mitochondria
no membrane-bound organelles
Describe a eukaryotic cell
Eukaryotic cell - Human cell
Nucleus with membrane
membrane bound organelles
Describe the smooth endoplasmic reticulum
smooth endoplasmic reticulum
no ribosomes attached
associated with lipid and steroid hormone production
associated with metabolism of toxin
Describe rough endoplasmic reticulum
Rough endoplasmic reticulum
Modifies proteins
has ribosomes attached
What is the function of the Golgi apparatus?
Golgi apparatus
packages up protein for transport out of the cell
Describe the mitochondria
Mitochondria
Bound by a phospholipid bilayer
The outer membrane contains pores
The inner membrane has cristae
The matrix contains most enzymes required for metabolising food molecules.
Describe lysosomes
Lysosomes
membrane-bound vesicles containing enzymes
What is the function of the cytoskeleton
Cytoskeleton
Supports and maintins cell shape
Holds organelles in position
helps move organelles around the cell
Name the surface projections supported by the cytoskeleton
projections supported by the cytoskeleton
Cilia and flagella
What are the major ELEMENTS used to construct human biomolecules?
major ELEMENTS used to construct human biomolecules
Hydrogen (H), Oxygen (O), Carbon (C), Nitrogen (N)
Carbon is the most versatile
Describe how functional groups define the biomolecular function
Groups of elements bonded to Carbon atoms (C) form function groups:
Hydroxyl
Aldehyde
Keto
Describe how the function of biomolecules also depend on the configuration of groups on the molecule
Configuration - the fixed arrangement of atoms in a molecule
Lots of biomolecules contain a double bond between C atoms, which is rigid conformations
2 distinct configurations - trans and ci
Can only interconvert between the two by breaking and reforming bonds
What are the 5 Chemical reactions of life
Redox reactions
Making and breaking C-C bonds
internal rearrangements
group transfer
condensation and hydrolysis reactions
Give an example of a redox reaction
Glucose -
NADH+ reduced to NAD
Give an example of making/breaking c-c bonds
Cleavage of glucose in the glycolysis pathway
Give an example of internal rearrangements
Glycolysis, rearrangement of the conformation of G6P (Glucose 6-phosphate) occurs before sugar is split
Give an example of group transfers
Glycolysis, phosphoryl group is transferred from ATP to f6p ( Fructose 6-phosphate)
Give an example of condensation and hydrolysis
Glucose polymers
Condensation chemical process 2 molecules are joined together to make a larger, more complex, molecule, with the loss of water.
Hydrolysis is the opposite to condensation. A large molecule is split into smaller sections by breaking a bond, adding -H to one section and -OH to the other.
Name the 3 classes of lipids
- triglycerides
- phospholipids
- steroids
Describe the structure of nucleic acids
Polymers of nucleotide monomers linked by 3’, 5’ phosphodiester bonds
formed of a base, sugar and phosphate
polymer - substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits.
monomer - a molecule that forms the basic unit for polymers, which are the building blocks of proteins
Name the pyrimidines
Cytosine
Thymine
Name the purines
Adenine
Guanine
Describe the structure of lipids
Fatty acids and glycerol
Fatty acids are long chains of carbon and hydrogen bonds
Describe water as a solvent
Water is a polar molecule =
charge within the molecule is not evenly distributed.
Giving slight +ve charge at the (H) hydrogen end and slight -ve charge on the (O) oxygen end.
Polarity allows hydrogen bonding
What is a hydrogen bond?
A weak bond between two molecules
resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other
Describe hydrophilic molecules and give examples
Can form hydrogen bonds
Then they dissolve the water - water (H) hydrogen bonding and Solute - Solute (H) hydrogen bonding is replaces with more energetically favourable
Solute - Water (H) hydrogen bonding
example - Ketone
Describe hydrophobic molecules
Do not dissolve readily in water
Arrange themselves in water to minimise disruption of hydrogen bonding among surrounding water molecules.
Define PH
The measure of hydrogen ion concentration
Describe weak acids and bases
Partially dissociated, can act as a buffer
What is a buffer
Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in PH
What can we use to calculate how the PH of a physiological solution will respond to changes in the conjugate (coupled, connected, or related.) acid or base
Henderson - Hasslebach equation
PH alpha [buffer] / [H-buffer]
What is metabolism catabolism?
Break down of complex molecules
What is metabolism anabolism?
Build-up (synthesis) of complex molecules
How is catabolism and anabolism interdependent?
catabolism and anabolism work together with the energy from catabolism providing the energy for anabolism
Describe metabolic pathways
Each step is catalysed by enzymes
spontaneous reactions move towards equilibrium
Enzymes function or selectively alter the rate of particular parts of the metabolic pathways.
Describe ATP hydrolysis
ATP hydrolysis:
hydrolyses ATP to ADP and phosphate group
Released free energy which is harnessed to drive thermodynamically unfavourable reactions.
through copping of catabolic thermodynamically favourable reactions.
What is a functional group?
Functional groups are specific groupings of atoms within molecules that have their own characteristic properties, regardless of the other atoms present in a molecule.
Common examples are
alcohols, amines, carboxylic acids, ketones, and ethers.
Plasma pH is proportional to carbonic acid concentration divided by bicarbonate ion concentration
Select one:
True
False
Plasma pH is proportional to bicarbonate ion concentration divided by carbonic acid concentration
(or CO2 levels as remember we can substitute CO2 for carbonic acid and get the same effect in terms of movement of pH)
describe - aetiology of a disease
The aetiology of a disease describes its causative factors. The process by which a disease develops is the pathogenesis.
saturated fatty acid
saturated fatty acid has no double bonds, all the bonds between carbon atoms are single bonds
Chylomicrons are important structures for
for carrying lipid around the blood. Proteins are generally water soluble so are readily transported in plasma. Lipids are not water soluble and thus need to be packaged into chylomicrons to ease transport in the blood.
amphipathic nature of proteins increases/decreases their water solubility
most proteins are amphipathic meaning they have a water loving (hydrophilic) and a water repellent (hydrophobic) part. By orientating themselves such that the hydrophobic part gets buried deep within the protein molecule and the hydrophilic part is on the outside exposed to the aqueous environment, the molecule becomes water soluble.
can Multipotent stem cells can differentiate into any cell type in the body?
NO
multipotent stem cells can differentiate in many, but not all, cell types.
Pluripotent stem cells can form any cell in the body. Adult stem cells are multipotent. Embryonic stem cells are pluripotent.
What are the main buffering agents in plasma?
bicarbonate ions are the main buffering agents in plasma.
Phosphate ions buffer intracellular fluid.
The conversion of NAD+ to NADH is an example of
is an example of reduction. NAD+ gains an electron to become NADH (remember OIL RIG where Reduction Is Gain (of electrons)). However NAD+ is an oxidising agent in that it oxidises another molecule at the same time as it is itself reduced to NADH.
Can Radiolabelled albumin can be used to measure extracellular fluid volume?
NO
albumin is a plasma protein and is thus confined to the plasma compartment. It cannot move into the interstitial fluid compartment. Because extracellular fluid (ECF) is a product of plasma volume and interstitial fluid (ISF) volume you need a marker that can move freely between plasma and ISF, but not intracellular fluid, in order to be able to measure ECF volume. Sucrose or radiolabelled Na+ would do the job nicely.
