Cells and organelles Flashcards

Question

Structure of secretory vesicles

Answer 1

-membrane bound spheres

Answer 2

-bud off from the Golgi -vesicles fuse with inner surface of the plasma membrane and release their contents (exocytosis)

Answer 3

-membrane bilayer surrounded vesicle; size 0.2-0.5µm -contains >50 hydrolytic enzymes for all major cellular macromolecules -inside is ~ pH 5.0.

Answer 4

-involved in organelle turnover/replacement – autophagy -lysosome fuses with other organelles -low pH is maintained by ATPase proton pump.

Answer 5

-surrounded by membranes -only visible by EM: not very electron dense; 0.5-1.5μm

Answer 6

-detoxification -phospholipid synthesis e.g. plasmalogens -oxidation of Very Long Chain Fatty Acids (VLCFA) -contains enzymes which generate (and degrade) H2O2

Answer 7

-hair-like extension of the plasma membrane -contains a central core of modified tubulin

Answer 8

-different types of cilia: (i) sensing movement of fluid (ii) moving liquid (iii) detection of sound

Answer 9

-protein and carbohydrate supporting network outside of cells -this is not an organelle

Answer 10

-mechanical support for cells/tissues

Answer 11

Single-celled organism in which the chromosome is a circular strand lying free in the cell (i.e. no nucleus) and has no membranous organelles e.g. Bacteria

Answer 12

One or more cells in which chromosomes are enclosed in a nucleus; typically have cytoplasmic, membrane-bound organelles, DNA divided into a series of linear chromosomes, and considerable differences occur between cells within the same organism. All complex organisms (plants, fungi, animals, protozoa, algae) are eukaryotes

Answer 13

Assemblage of nucleic acid (DNA or RNA) and proteins (and often other molecules) which is parasitic on prokaryotes/eukaryotes. Viruses invade cells, subvert their protein synthesis machinery to make more viruses instead of normal cell proteins, then escape to infect other cells. Viruses are not cells or organisms in the strict sense (lack a plasma membrane and only operate chemically within host cells).

Answer 14

Semi-independent, living unit within the body, (in unicellular organisms, completely independent) in which are sited the mechanisms for metabolism, growth and replication (by division). It consists of an aqueous solution of organic molecules surrounded by a membrane

Answer 15

Subunit within a cell, with a defined structure and performing specific, integrated activities. Some are bounded by membranes, others are non-membranous e.g. ribosomes

Answer 16

Organised assembly of cells and their extracellular products which carry out similar and coordinated activities within the body (connective, lymphoid)

Answer 17

Assembly of tissues coordinated to perform specific functions within the body (eye, ear, heart, lungs, liver)

Answer 18

Assembly of organs with specific, related activities, sharing regulatory influences (e.g. respiratory). OR it may be a diffuse functional network of cells situated in many parts of the body, sharing specific activities (e.g. immune)

Answer 19

1000 - 5000um^3 Exceptions: -erythrocyte (100um^3) -oocyte (4000000um^3)

Answer 20

Rate of diffusion: -movement of metabolites within cell -uptake of oxygen from outside cell -movement of mRNA from nucleus -movement of vesicles inside cell

Answer 21

-Cytoskeleton to actively move things around cells -Creation of giant cells with multiple nuclei so gene expression can occur in multiple places -Gap junctions between cells for efficient movement of metabolites

Answer 22

-Only nucleus and plasma membrane

Answer 23

-Sample preparation is highly artificial -Cells are dead, fixed and dehydrated

Answer 24

Eye: 0.2mm Light: 10mm - 200nm Electron: 10mm-0.1nm