Cells Flashcards
What is Brownian motion?
Temperature dependent movement where molecules move spontaneously and do not require energy.
What are the six main functions of blood?
1) Transport
2) Haemostasis
3) Homeostasis
4) Heat distribution
5) Immunity
6) Connective tissue
Normal blood volume?
5L
What is present in erythrocytes? (2)
Haemoglobin and carbonic anhydrase
What does carbonic anhydrase do?
Convert carbon dioxide into bicarbonate.
What are immature erythrocytes called and how do they differ?
Reticulocytes and they have function ribosomes present.
In what cases are reticulocytes normally seen?
Anaemic and chemotherapy patients
What is the life span of an erythrocyte?
120 days
What are the precursors to an erythrocyte?
Precursor that initially produces haemoglobin that then loses their organelles.
What is the structure of haemoglobin?
Four polypeptide chains with four heme groups (where the oxygen binds)
What is the oxidised form of haemoglobin and how does it differ in function?
Methaemoglobin and it cannot transport oxygen
How does binding of oxygen affect haemoglobin’s affinity to oxygen?
Binding of oxygen causes conformational changes making it easier for further oxygen molecules to bind, increasing affinity. Known as cooperative binding.
What is the haematocrit?
Packed cell volume or portion of blood that erythrocytes make up. Normal is 0.6.
What is microcytic anaemia?
Small erythrocytes and haemoglobin synthesis failure. Common with heavy menstruation, cancers and parasitic infections.
What is normocytic anaemia?
Acute loss of blood.
What is macrocytic anaemia?
Large erythrocytes but overall decrease in erythrocytes so less haemoglobin. Common in pregnancy with folic acid deficiency or vegetarians with B12 deficiency.
What are the five main cell types of leukocytes?
- Neutrophil
- Basophil
- Eosinophil
- Macrophage
- Monocyte
Which three leukocyte types are known as polymorphonuclear granulocytes?
Neutrophils, basophils and eosinophils. They contain inflammatory mediators in cytoplasmic granules.
Which cell type is responsible for humoral immunity?
B lymphocytes
What is a blast formation?
A reaction caused by the appearance of foreign antigen causing proliferation of T cells.
When do monocytes become macrophages?
In tissues.
What is leukopenia?
Low white blood cell count, common in chemotherapy and HIV patients.
What is leucocytosis?
Raised white blood cell count caused by infection.
What are platelets derived from?
Megakaryocytes
What is the life span of a platelet?
8-10 days
What do platelets produce and what enzyme is involved?
Thromboxane using the cycloxygenase enzyme.
How do pores in facilitated diffusion work?
They conceal the ionic charges present from the hydrophobic core of the bilayer.
What is a symporter?
Cotransporter that moves two substances in the same direction.
What is an antiporter?
Molecules moved in opposite directions
What is pinocytosis?
Engulfment of extracellular solute by membrane, creating small intracellular, membrane-bound vesicles.
What are the five main infectious agents and an example for each?
1) Bacteria (leprosy)
2) Viruses (rabies)
3) Fungi (ringworm)
4) Helminth parasites (hookworm)
5) Protozoa (malaria)
Which cell type is peptidoglycan present in the cell wall?
Prokaryotic cells
How do bacteria divide?
By binary fission.
Where is the genetic information found in bacteria?
Nucleoids
How do protozoa cause infections?
By ingestion or via a vector.
Which type of infectious agent is visible to the naked eye?
Helminth parasites
How do protozoa replicate?
Binary fission
What is the order of increasing size between different cell types and organelles?
Viruses < bacteria < organelles < eukaryotic cells
What stimulates erythroietin?
Testosterone and low O2 concentration.
What is meant by pernicious anaemia?
Anaemia caused by B12 deficiency.
