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.
How surface area affect the rate of diffusion?
The larger the surface area over with diffusion occurs, the higher rate of diffusion.
