BIOLOGICAL MEMBRANES

Question 1

What are membranes

Answer 1

cover the surface of every cell
surround ost organelles
keeps cellular components inside the cell
selected molecules can move in and out of the cell
site for biochemical reactions
allow for the cell to change shape

Question 2

what is a phosolipid

Answer 2

phosphate group / hydrophillic head
fatty acids chains tail / hydrophobic tail

Question 3

membranes within cells

Answer 3

chloroplasts
mitchondria

Question 4

what do the chloroplasts do

Answer 4

thylakoid mebranes contain chlorophyll
1st of photosynthesisi happens here

Question 5

what does the mitochondria do

Answer 5

cristae increases surface area
locslize the enzymes for areobic respiration

Question 6

what is the fluid mosaic model of cell emebrane

Answer 6

fluid = proteins and lipids are able to move within the membrane

Question 7

components of the cell membrane

Answer 7

glycolipid
glycoprotein
cholesterol
pore
peripheral protein
filaments of cytoskeleton
integral protein
phospholipid bilyaer

Question 8

what is the phospholipid bilayer

Answer 8

structural basis
acts as a barrier

Question 9

what is peripheral proteins

Answer 9

sit on the outisde of the membrane
ones on the extra cellular side =
act as receptors for hormones
neurotransmiters
involved in cell recognition
many are glycoproteins
ones of the cytosolic side =
involved of cell signalling and chemical reactions
they can move into the cytoplasm

Question 10

what is an integral proteins

Answer 10

carrier molecules / channels
help transport substances that cannot diffuse across the membrane ( sugars and amino acids)
others are receptors for hormones neurotransmitters and ezymes for catalyzing reactions

Question 11

what is cholesterol

Answer 11

controlling menrane fluidiity
important at keeping a normal body temperature without it cells would burst open
the more chlosertol the less fluid

Question 12

what are pores

Answer 12

type of integral protein
help certain molecules that can move in and out of the cell

Question 13

what is the cytoskeleton

Answer 13

maintains the cells shape
involved in the movement of the cell ( muscle contraction )
aids cell to cell attachment

Question 14

what are glycolipids

Answer 14

act as receptors
involved in cell recognition
involved in membrane stability
& cell to cell attachment

Question 15

what are glycoproteins

Answer 15

involved in cell recognition
membrane stability
receptor molecules

Question 16

what is diffusion

Answer 16

the NET movement of particles DOWN a concetration gradient
HIGH TO LOW
no metabolic energy is expended during diffusion = passive transport
e.g gas exchange across the respiratory surfaces

Question 17

what is facilitated diffusion

Answer 17

large or hydrophllic particles
( glucose and amino acids)
that need to move across the membrane through a integral proteins