Module 2 - Cell structure Flashcards
(19 cards)
Eukaryotic cells
Larger than prokaryotic cells, DNA contained in a nucleus, multicellular
Cell surface membrane structure and function
Structure: Phospholipid bilayer with proteins and cholesterol in it. Glycolipids and glycoproteins on the surface.
Function: Cholesterol provides strength and reduces fluidity, proteins are for transport and glycolipids and glycoproteins for cell recognition and recepetors
Nucleus structure and function
Structure: Double membrane nucleur envelope with chromosomes, linear DNA and one or more nucleolus
Function: rRNA production and makes ribosomes. DNA and transcription occur there.
Mitochondria
Structure: double membrne, inner membrane folded to form criste nd contains a fluid centre (matrix)
Function: site of aerobic respiration and ATP production
Chloroplasts
Structure: double membrne containing thylakoids with chlorophyll with fluid centre (stroma)
Function: site of photosynthesis and stroma contains enzymes needed for light-dependent stage
Golgi apparatus and vesicles
Structure: stacks of membranes creating flattened sacs (cisternae) surrounded by small, hollow vesicles
Function: proteins and lipids modified, carbs added to proteins to form glycoproteins
Lysosomes
Structure: formed when golgi apparatus contains hydrolytic enzymes
Function: releases lysozymes
Ribosomes
Structure: granules in cells made of proteins and rRNA
Function: site of translation in protein synthesis
RER & SER
Structure: sheets of membranes linked to nucleus to form network of cisternae
Function: RER has ribosomes on outer surface (site of protein and glycoprotein synthesis. SER creates, stores and transports lipids and carbohydrates
Cellulose
Structure: made of polysaccharides and cellulose in plants and chitin in fungi
Function: structural strength and prevents cells bursting during osmosis
Cell vacuole
Structure: in plants, single membrane sac filled with fluids containing salts, sugars and amino acids.
Function: support for cell, stores amino acids and sugars and can contain pigments to attract pollinators
Cytoskeleton
Structure: found in cytoplams all over a cell
Function: mechanical strength, helps transport in cells, allows movement, many organelles are bound to it
Prokaryotic cells
key example: bacterial cells, no nucleus, no membrane bound organelles, DNA stored in a single circular molecule, cell wall made of glycoprotein called murein
Differential staining
chemical stains used to stain different structures different colours
Gram staining
Visualises different bacteria and uses the stains Crystal violet and safranin (gives a purple colour and red
Define magnification and resolution
Magnification: how many times larger image size and object size are
(mag= image size/object size)
Resolution: the minium distance between 2 objects in which they can be viewed as separate
Light microscopes
poor resolution due to long wavelength of light, small organelles not visible but living samples can be examined and produces a coloured image
Electron microscope
high resolution due to short wavelength of light and image is generated using electromagnet to focus the beam of electrons, it must be in a vacuum so is non-living
Rules for scientific drawings
In pencil, includes a title, includes magnification, annotations with no arrowheads and horizontal lines only, no colour, shading in or overlapping lines
