Life at the cellular level Flashcards
What are prokaryotic cells?
- bacteria, archaea
- lack nuclear membrane
- no membrane bound organelle
What are eukaryotic cells?
- animals, plants, fungi, algae, protozoa
- nucleus with membrane
- membrane bound organelles
What are the characteristics of cell membranes?
- also called plasma membrane or plasmalemma
- phospholipid bilayer
- selective barrier
- receptors embedded in membrane to detect chemical signals
What are the characteristics of the cytoskeleton?
- supports and maintains cell shape
- internal cell order
- intracellular transport
- movement
- assembly of cells into tissues
What are the three types of cytoskeleton?
1.) microfilaments
2.) intermediate filaments
3.) microtubules
What are microfilaments?
- thinnest cytoskeleton
- units of actin put together (globular protein)
What are intermediate filaments?
Made up of fibrous proteins such as keratin and neurofilament protein
What are microtubules?
- largest cytoskeleton
- lots of functions
- made of tubulin put together (globular protein)
What are the two types of cell surface projections?
Cillia and flagella
What is cillia?
- short
- usually many present
- move with stuff power stroke and flexible recovery stroke
What is flagella?
- longer than cillia
- usually one of two present
- movement is stroke like
What are the characteristics of the nucleus?
- contains DNA
- nucleoli are sites of RRNA synthesis and ribosomal assembly
- enclosed in nuclear membrane/envelope (phospholipid bilayer)
- closely associated with RER
What are the characteristics of endoplasmic reticulum?
- membrane bound organelle
- rough and smooth variations
- RER has ribosomes attached
- RER modifies proteins
- SER has no ribosomes attached
- SER is mainly associated with lipid and steroid hormone production and metabolism of toxins
- ribosomes synthesise proteins
What are the characteristics of golgi apparatus?
- membrane bound organelle
- packages up protein in preparation for transport out of the cell
What are the characteristics of mitochondria?
- membrane bound organelle
- outer membrane contains pores
- inner membrane has cristae (folds)
- matrix contains most of the enzymes required for metabolising food molecules
- circular DNA
- can self-replicate
- synthesise most of their own proteins
What are the characteristics of lysosomes and peroxisomes?
- membrane bound vesicles containing enzymes
- lysosomal enzymes are degradative, responsible for digestion of biological materials or engulfed particles
- peroxisomal enzymes degrade long-chain fatty acids and other foreign toxic molecules and breakdown the hydrogen peroxide produced by the reactions
What is apoptosis?
Controlled, programmed cell death
What is necrosis?
Untimely death of cells
What form to monosaccharides occur in?
D- from
What form to amino acids occur in?
L- form
What is OIL RIG?
Oxidation
Is
Loss
Reduction
Is
Gain
What is an example of a reducing agent?
NADH
What is an example of an oxidising agent?
NAD+
What are characteristics of tricylglycerides?
- also called triglycerides or fats
- glycerol + 3 fatty acid chains
- insoluble in water
- storage lipids (in adipocytes)
- non polar, hydrophobic
What is a non-polar covalent bond?
Two atoms share a pair of electrons with each other
What is a polar covalent bond?
A pair of electrons is unequally shared between two atoms, the more electronegative atom pulls the electron towards itself becoming partially negative
Is water a polar or non polar molecule?
Polar
What is a hydrophilic molecule?
Molecules that dissolve in water
- sugars
- alcohols
- aldehydes
- ketones
- compounds with N-H groups
- charged particles such as ions
Water forms a “screen” around charged particles
They are all polar molecules
What is a hydrophobic molecule?
Molecules that do not dissolve in water, but do dissolve in lipid
- fat soluble vitamins (A, D, E, K)
- lipids
- steroid hormones
- oxygen
Arrange themselves in water so as to minimise contact with surrounding water molecules —> called hydrophobic effect
They are non polar molecules
What is an amphipathic molecule?
Molecules which contain both hydrophobic and hydrophilic parts
- many proteins are amphipathic
- hydrophobic regions of the protein chain are on the inside and hydrophilic regions on the outside
- therefore water soluble
examples —> cholesterol, phospholipids
What are liposomes and micelles used as?
Drug-delivery systems
What values for blood pH are normal?
7.35-7.45
What values for blood pH are acidosis?
7-7.35
What values for blood pH for alkalosis?
7.45-7.8
What are the two most important buffer systems?
Phosphate buffer system and bicarbonate buffer system
What is the Henderson-Hasselbach equation?
pH = [A-] / [HA]
What does an increase in CO2 cause?
Respiratory acidosis
What does a decrease in HCO3- cause?
Metabolic acidosis
What does a decrease in CO2 cause?
Respiratory alkalosis
What does an increase in HCO3- cause?
Metabolic alkalosis
What is the 1st law that governs energy change?
Energy can be converted from one form to another but the total energy of the universe remains constant
What is the 2nd law that governs energy change?
All energy transformations ultimately lead to more disorder in the universe i.e. increase that entropy
What is entropy?
A gauge of randomness or chaos within a closed system, as usable energy is irretrievably lost, disorganisation, randomness and chaos increase
