Eukaryotic cells Flashcards
What is the cell surface membrane made up of?
-Phospholipid bilayer
-Cholesterol
-Membrane proteins
What model is the cell surface membrane?
The ‘Fluid Mosaic Model’
What does the ‘Fluid Mosaic Model’ mean?
-Fluid = the phospholipids can move past each other, flexible and can change shape
-Mosaic = made up of many things, proteins are embedded on top and vary in position
-Model = an representation but is not certified correct and is still being developed
What does the cell surface membrane do?
To signal and identify that it is not foreign to allow the correct hormones in
What is the phospholipid bilayer?
-The molecule has 2x fatty acid
-Phosphate group is polar
-It is a barrier between internal and external contents of the cell
-A site for chemical reactions to take place
What does the cholesterol do?
-Increases the membranes strength and flexibility
-Some cells have more cholesterol than others making them more stable and less likely to get damaged
-Controls fluidity (less cholesterol = less fluidity)
What is an integral protein?
Intrinsic/integral
-Fully embedded in the membrane
-Goes from one side to another
-Forms protein channels and carrier proteins
What is a peripheral protein?
Extrinsic/peripheral
-Only on one side of the membrane
-e.g glycolipid or glycoprotein
What is the rough endoplasmic reticulum?
-Makes the proteins
-Where modification starts (e.g folding)
-A network of membranes forming cavities
-Covered in 80S ribosomes
-Involved in protein synthesis
What is the golgi?
-A stack of membranes forming cavities
-Packages secretions into vesicles
-Modifies the proteins further, usually by adding a carbohydrate chain to form a glycoprotein
-Has a flattened stack called cristernae
What is lysome?
-A protein which stays within a vesicle and is used as an enzyme to store and destroy pathogens in phagocytosis
-They are then secreted into the bloodstream
-They remain on the cell surface membrane
What is the cell theory?
A concept that states that cells are a fundamental unit of structure, function and organisation in all living organisms
What are the 3 principles of the cell theory?
-All organisms are made of cells
-All existing cells are produced by other living cells
-The cell is the most basic unit of life
Who was Robert Hooke?
First person to look at cells and name them
What does the vacuole do?
-Can occupy up to 80% of the cell
-Has a specialised membrane called a tonoplast
-Filled with cell sap
-Used to store pigments, proteins and waste products
-Keeps the cell turgid and upright
What do chloroplasts do?
-Formed by an unspecialised organelle called a leusoplast
-Allows plants to make their own food
-Contains chlorophyll making them green to attract sunlight for photosynthesis
-Is the site of photosynthesis
-Has its own DNA
-Has a double membrane
-Only found in some plant cells
What does the cell wall do?
-Gives strength and support
-Has mitochondria and creates its own ATP
-Made of insoluble cellulose
-Made of several layers
-Prevents osmotic lysis = stops the cell from bursting
-Found in all plant cells
What is a eukaryote?
Any organism consisting of one or more cells that contain DNA in a membrane bound nucleus separate from the cytoplasm
What is the protoplasm?
A term used to describe the cytoplasm and the nucleus combined
What is the cytoskelenton?
-A feature of all eukaryotic cells
-Dynamic with a 3D structure that fills the cytoplasm
-Contains microfilaments and microtubules
-Provide structure and keep organelles in place
-Linked to cell movement and transport in the cell
What is the nucleus?
-Largest organelle
-Double membrane with pores (nuclear envelope)
-Chemicals pass through the pores so the nucleus can control events in the cytoplasm
-Nuclear envelopes contain nucleic acids and proteins
-Chromatin is DNA bound to proteins when it is not actively dividing
-Has a nucleolous
-Involved in producing ribosomes
What is the mitochondria?
-Involved in cellular respiration and producing ATP
-Lots of mitochondria means the cell needs a lot of energy
-Outer and inner membrane with its own DNA
-Own DNA allows it to replicate when the cell undergoes divison
-Cristae = folds creating a large surface area
-Fluid matrix surrounds the cristae
-Involved in the endosymbiotic theory = the mitochondria was once its own cell
