Topic 6 Flashcards
Definition of cells according to cell theory
All cells arise from pre existing cells and cells require and use energy
what is the name for the cell membrane model
the fluid mosaic model
fluid because the membrane is flexible and able to move, the proteins can move around in the membrane therefore changing their position.
mosaic because it is made up of many different components combined together
what is the the fluid mosaic model (cell membrane) made up of?
phospholipid bilayer, proteins, cholesterol and polysaccharides.
what are the components that make the phospholipid bilayer and what is their purpose?
Components:
hydrophilic heads (glycerol) - which attracts water soluble or charged particles [Hydro = water, philic = love]
hydrophobic tails (fatty acids) - which repel water soluble or charged particles [hydro = water, phobic = fear]
purpose:
the tightly packed and bound phospholipids act as a physical barrier against large molecules
they block water soluble (hydrophilic) molecules from passing through due ti the hydrophobic nature of the tails.
where is cholesterol found in the cell membrane and what is their purpose?
found in-between the tails of the phospholipids in animal cells
helps to maintain the strength/structure of the membrane and prevent sit from being too fluid.
what are the types of cell membrane proteins and what is their function?
integral proteins - permanently in the bilayer
- proteins stick out and bind other cells specific proteins or adjacent cells
peripheral proteins - tend to move around the membrane
hormone binding sites: protein receptors e.g. glycoprotein
- have complementary shape to hormones in the extracellular environment. they bind these hormones and send messages inside cells
cell communication:membrane proteins
- through direct contact with other cells or through hormones
cell transport: channel proteins and protein pumps/transport proteins
- allow for transport of specific molecules across the cell membrane whether by diffusion (channel proteins) or using active transport requiring energy (protein pumps)
what way does the concentration gradient for channel proteins move specific molecules?
with their concentration gradient, passive process
what way does the concentration gradient for protein pump/carrier proteins move specific molecules?
against their concentration gradient, requires energy, active transport
what are the two major cell types?
eukaryotes and prokaryotes
example of a prokaryotic cell
bacterial cell
prokaryotic cells are…
A) unspecialised cells with high levels of organisation
B) specialised cells with low levels of organisation
C) unspecialised cells with low levels of organisation
D) specialised cells with high levels of organisation
C
what membrane bound organelles DO prokaryotic cells have?
plasma membrane and ribosomes
where is the DNA located in prokaryotic cells? and what shape is the DNA?
In the cytoplasm and is found in a single cellular loop
are prokaryotic cells…
A) multicellular
B) unicellular
B
Eukaryotic cells are
A) unspecialised cells with high levels of organisation
B) specialised cells with high levels of organisation
C) unspecialised cells with low levels of organisation
D) specialised cells with low levels of organisation
B
