Читать книгу Cell Biology - Stephen R. Bolsover - Страница 55

1 2.1 Theme: Membranesthe membrane or set of membranes surrounding the ERthe membrane or set of membranes surrounding the Golgi apparatusthe membrane or set of membranes surrounding the lysosomethe membrane or set of membranes surrounding the mitochondrionthe membrane or set of membranes surrounding the peroxisomethe plasma membraneFrom the above list, select the membrane that best fits the descriptions below.a double layer comprising an inner and an outer membraneis continuous with a membrane surrounding the nucleusforms a set of flattened sacks called cisternaeoften contains connexons as integral membrane proteinssurrounds a space containing calcium ions at a much higher concentration than in the cytosol. This store of calcium ions can be released into the cytosol upon cell stimulation. (Other such releasable calcium stores may exist in cells, but this is the largest.)

2 2.2 Theme: Organelles in eukaryotic cells endoplasmic reticulumGolgi apparatuslysosomemitochondrionnucleusperoxisomeFrom the above list of organelles, select the organelle described by each of the descriptions below.a major site of protein synthesiscontains many powerful digestive enzymescontains small circular chromosomescontains the enzyme catalasefilled with chromatinmade up of flattened sacks called cisternaemost of the cell's ATP is made hereusually found at the cell center

3 2.3 Theme: Transport across membranescan move from the cytosol of one cell to the cytosol of a neighboring cell, crossing the lipid bilayer component of each cell's plasma membrane as it does socannot cross lipid bilayers, but can move from the cytosol of one cell to the cytosol of a neighboring cell via gap junctionscannot move to a neighboring cell either by crossing the lipid bilayer component of the plasma membrane or via gap junctionsAbove we list three different possible constraints on the movement of a cytosolic solute. For each of the molecules below, state which of the three conditions apply.an RNA molecule of Mr = 10 000. As we will describe later, in Chapter 5, RNA molecules bear many negative chargesinositol trisphosphate, a small charged molecule of Mr = 649K+ (atomic weight = 39)nitric oxide (NO) (Mr = 30)

Review question covering chapters 1 and 2: Some basic components of the eukaryotic cell

Identify each of the cellular components below from the figure above.

1 cytosol

2 internal membranes

3 mitochondrion

4 nucleus

5 plasma membrane