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What type of membranes surround the nuclear envelope?
Phospholipid bilayers
Why does the nuclear envelope have pores?
To control the passage of ions, molecules and RNA between the nucleoplasm and cytoplasm
What is the nucleoplasm?
A semi-solid fluid inside the nucleus where chromatin and the nucleolus are found
What is the function of the nucleus?
Controls actions of the cell, contains DNA with instructions for the synthesis of proteins
What molecules are found in the nucleolus?
Proteins, RNA + DNA
How is the purpose of the nucleolus different to that of the nucleus?
nucleolus as a site at which ribosomes are made, while nucleus is site of DNA replication and transcription
What is the function of mitochondria?
Produce ATP via aerobic respiration
What is the inner layer of membrane folds in the mitochondria called?
Cristae
What are found in the mitochondrial matrix?
Enzymes for respiration
What is a plasma membrane?
A partially-permeable barrier between cell and outside environment
What is the name of the model given to describe plasma membrane structure?
Fluid mosaic model
What does the fluid mosaic model suggest?
Membranes are made up of a variety of components that continuously move around
Why are phospholipids described as amphipathic?
They have both hydrophobic and hydrophilic regions
Which ways do the hydrophobic/philic regions of the phospholipids face?
Phobic inwards, philic outwards
What is the purpose of phospholipids being amphipathic?
Allows for bilayer to form with the hydrophobic tails turned inwards away from aqueous environment and hydrophilic heads turned outwards
What is the function of plasma membranes?
Protects cell from surroundings, partially permeable, cell signalling
What is the function of a cell wall?
Provides structural support and shape to cell
What is the cell wall in plant and fungi made of?
Plants - cellulose, fungi - chitin
What is the cytoskeleton?
A network of protein fibres
What is the function of the cytoskeleton?
Maintaining shape of cell, securing organelles in position
what are thylakoids?
stacked fluid-filled membrane sacs
Where are thylakoids found?
In the inner membranes of chloroplasts
What is each stack of thylakoids called?
Grana
What links grana in chloroplasts?
Lamellae
What is stroma?
The fluid enclosed by inner membranes in chloroplasts
what is the function of the Golgi apparatus?
To store and transport modified proteins and lipids to cells
What is the function of the smooth endoplasmic reticulum?
Making and processing lipids
What is the function of the rough endoplasmic reticulum?
Processing and folding proteins
What is the function of ribosomes?
Protein synthesis
Where can ribosomes be found in the cell?
Cytoplasm or cytoplasmic side of endoplasmic reticulum
Describe the structure of a centriole
Cylindrical, paralleled microtubules with a central cavity
In what arrangement are centrioles found in the cell?
As pairs at 90° to one another
What is the function of centrioles?
Organise spindle fibres during cell division
What is the function of flagella?
Used by organisms for locomotion
What protein are microtubules in flagella made from?
Tubulin
What is the function of cilia?
Help move substances internally in organisms
What is the cytoskeleton?
Network of protein fibres
Function of cytoskeleton
Maintains shape of cell, securing organelles in position
Magnification
Process of enlarging an object in appearance
Resolution
Ability of a microscope to distinguish 2 adjacent structures as separate
Describe how light microscopes work
Visible light passes and is bent through the lens system to enable the user to see the specimen
In what type of microscope can the specimen be alive?
Light microscopes
Maximum resolution and magnification of light microscopes
0.2 micrometers, x 1500
Describe how TEM works
Electron beam penetrates cell and provides details of internal structures
Describe how SEM works
Electrons move back and forth across a cell’s surface to show surface characteristics
What type of microscope can give 3D images?
Scanning electron microscope
Equation for magnification
M = image size/actual size
Note 
Flashcard (52)