Cells Flashcards
List the main functions of the blood
- transport
- heat distribution
- immunity
- haemostasis (reduce bleeding)
- homeostasis
List the major components of blood
- Hormones
- Vitamins
- 02
- CO2
- H20
- Heat
- Metabolic Waste eg. Urea, lactic acid
8.Products of digestion eg. Fatty acids, glucose,
amino acids
What is macrocytic anaemia and what causes it?
Failure of DNA synthesis so progenitor cells red division so fewer but larger RBC
Causes:
- Folic acid (required thymine synthesis) deficiency: pregnancy
- Vit B12 (needed for folic acid synthesis) deficiency: autoimmune diseases that destroy B12 uptake in gut eg. pernicious anemia, vegetarians and vegans
How to B lymphocytes assist phagocytosis?
Precipitation - come out of solution
Agglutination - clumping
Opsonisation - coast in antibody
Neutralisation - prevent attachment to tissue
What is the abundance of polymorphonuclear granulocytes?
Neutrophils (abundant, phagocytic)
Basophils - lowest conc in blood (allergy)
Eosinophils (inflammation)
What are the characteristics of platelets:
Derived from megakaryocytes
Very small, No nucleus but many organelles
What occurs when platelets are acitvated?
Produce filapodia when activated
Produce thromboxane A2 using cyclooxegenase enzyme
What are the main functions of plasma?
Exert osmotic pressure to maintian blood volume
Platelet aggregation - fibrinogen
Albumins and Globulins - carry water insoluble drugs, bile salts, hormones
How does shigella cause infection?
has no flagella enters cell –>vacuole lysis–>intracellular replication–>cell to cell spread (using host actin)
What are the characteristics of fungus?
- multicellular
- occur as yeasts (bud) , filaments (divide) or both
What are the characteristics of protozoa?
- eukaryotic and unicellular
- replicate via binary fission or formation of trophozoites (stage in life cycle where absorb nutrients from host) inside cell
- infections acquired via ingestion of vector
What are characteristics of Helminth parasites?
- multicellular eukaryote
- metazoa
- have life cycles outside of human host
What are the types of cell movement
- Hydrolysis of ATP
- Transport of molecules against a concentration gradient
- Movement of organelles
- Adaptation of hair cells in the ear
- Movement of cell membranes, ruffling
- Growth and migration of cells - Nerve growth, development
- Cell division, movement of chromosomes
- Muscle contraction (skeletal and smooth), the heart beat
- Diffusion
- Brownian motion
What are the mechanisms of cancer?
- switch off/on of “don’t/do divide” signals
- loss of correction mechanism on DNA copying
- loss of escape mechanism from cell division
- loss of limit on number of times a cell can divide
- loss of control keeping cell within tissue boundaries
- ability to evade body defence mechanisms
- ability to recruit blood vessels to growing tumour
- ability to migrate into blood stream or lymph vessels
- ability to establish tumours in the “wrong” tissue - metastasis
What is pinocytosis?
bulk transport mechanism membrane engulfs EC solute and small molecules which end up in membrane bound vesicles
What is the function of cholestrol?
- Decreases permeability
- Modulates membrane stiffness
- Affects interactions with cytoskeleton
What is the structure of cholestrol?
- Polar head
- Rigid steroid ring structure
- Nonpolar hydrocarbon tail
How does the cell membrane form a bilayer?
- Form miscelles/droplets, can also arrange themselves into bilayers called lipsosomes
- Unsaturated chains sparsely packed, saturated chains more densely packed - lipid rafts
What is the role of proteins in the bilayer?
- Proteins increase fluidity by breaking up order of membrane
- Protein regions in core arrange themselves in alpha helical conformation
- constrained in lateral movement by intracellular actin cytoskeleton fences
What are the characteristics of a phospholipid?
- amiphilic- have hydrophilic and hydrophobic components
- Hydrophilic groups contain anion and cation groups - net charge either anionic or neutral
- Can be sparsely or densely packed
- Glycolipids on outside and Negative charges on inside
What are the polar hydrophilic made of head?
- Choline
- Phosphate
- Glycerol
What is the function of the Na-K pump?
- Prevents dissipation of ionic gradients, required to perform particular functions - cell doesn’t want equilibrium
- Maintains osmotic balance
- Drives sugar and AA transport
What is the structure of the Na-K pump?
2 polypeptide chains:
Alpha: spans membrane 10x to form hydrophilic core
Beta: controller
What is the energy drive of the Na-K pump?
- Driven by phosphorylation of aspartyl residue
- Followed by hydrolysis of aspartylphosphate
