Ch.3 Movement of substances across cell membrane Flashcards
What are the main components of the cell membrane?
- phospholipids (磷脂)
- proteins
The structure of the cell membrane can be presented by ______ ______ model.
fluid mosaic (流動鑲嵌)
Phospholipid molecules are arranged in a ______, with { hydrophilic / hydrophobic } heads pointing outwards and { hydrophilic / hydrophobic } tails pointing inwards.
bilayer (雙層);
hydrophilic (親水的);
hydrophobic (疏水的);
[T/F]
Phospholipid molecules can move vertically.
F
Phospholipid molecules can move laterally (橫向地).
Protein molecules are interspersed among the ___________ molecules in a ______ pattern.
phospholipids; mosaic
a. embedded half-way | b. span | c. attached to
Some of the protein molecules are () to the surface of the phospholipid bilayer, some are () in the bilayer and others (_) the entire bilayer.
attached; embedded half-way; span
Carbohydrates are attached to some proteins to form ____________.
glycoproteins
i) channel proteins
ii) carrier proteins
(__) bind to certain substances and transport them to the other side of the cell membrane.
(__) provide channels for certain substances to move across the cell membrane.
ii. carrier proteins
i. channel proteins
i) receptors ii) antigens iii) enzymes
(__) are glycoproteins for cell recognition.
(__) bind to chemical messengers (e.g. hormones) outside cells; the binding may turn on certain activities in the cells
(__) speed up chemical reactions
ii. antigens
i. receptors
iii. enzymes
________ proteins provide channels for certain substances to move across the cell membrane.
Channel
_______ protiens bind to certain substances and transport them to the other side of the cell membrane.
Carrier
_______s bind to chemical messengers (e.g. hormones) outside cells; the binding may turn on certain activities in the cells
Receptors
________ are glycoproteins for cell recognition(識別).
Antigens
______s speed up chemical reactions.
Enzymes
The cell membrane is mainly made up of phospholipids and proteins → make the cell membrane ___________ _________.
differentially permeable
The phospholipid molecules are arranged in a bilayer with a hydrophobic core → only small, { polar / non-polar } molecules can dissolve in and move across the phospholipid bilayer.
non-polar
Some protein molecules on the cell membrane act as channels or carriers → small, { polar / non-polar } molecules and small _____s are transported by channel proteins or carrier proteins.
polar; ions
The phospholipid molecules can move laterally → makes the cell membrane _____ in nature; allows the cell membrane to change shape and _____ during phagocytosis(吞噬) and cell division.
fluid(流質的); fuse(融合)
Factors affecting the structure of the cell membrane and hence its premeability include ___________ and the presence of organic _______ (e.g. alcohol).
temperature; solvents(溶劑)
When the __________ rises, the permeability of the cell membrane increases. _______ can even damage the membrane, causing it to become fully premeable.
tempreature; Boiling
Organic solvents dissolve the phospholipids and damage the cell membrane, causing the __________ of the membrane to increase.
permeability
Diffusion is the ____ ________ of particles from a region of higher concentration to a region of lower concentration (i.e. down the concentration _______) until the particles are _____ly distributed.
net movement; gradient; evenly
How concentration gradient affect the rate of diffusion?
The steeper the concentration gradient is, the higher the rate of diffusion.