Module 2.1 Flashcards
Cell structure
Light microscope image properties
2D
Coloured
larger area viewed
Low magnification
Low resolution
Light microscope benefits
Can view live specimens
Coloured
Can view whole specimens
Small/light/portable
No training needed
Cheap
Transmission electron microscope image properties
2D
black and white
high resolution
high magnification
scanning electron microscope image properties
3D
black and white
high resolution
high magnification
Electron microscope benefits
Can view organelles
High magnification and resolution
Electron microscope limitations
Expensive
Needs training
Large/heavy/cannot be moved
Specimen must be dead
Light microscope limitations
Cannot view organelles
low magnification and resolution
Why is staining used
To help distinguish between different elements within a cell and view cells which are colourless
Magnification formula
magnification = image size/ actual size
resolution definition
The ability to differentiate between points on an image
Magnification definition
The amount of times larger an image appears compared to its actual size
nucleus function
Control centre of the cell
Stores the genome
Transmits genetic information
Provides instructions for protein synthesis
Nucleus structure
Has the nuclear envelope surrounding it
DNA organised in chromosomes around histone proteins
Nuclear envelope function
control what enters the nucleus
Protects the genetic information from the rest of the cell
has nuclear pores for ribosomes and mRNA to leave through
Nuclear envelope structure
Double membrane
Has holes in called nuclear pores for mRNA to leave through
Has areas where the 2 membranes fuse for ribosomes and dissolved substances to move through
Rough endoplasmic reticulum function
Large surface area for ribosomes to lie on
Proteins actively pass through the membrane into cisternae to be transported to the Golgi
Transport system, cisternae from channels for substances to be transported from one area of the cell to another
Smooth endoplasmic reticulum function
Has enzymes for lipid metabolism e.g. synthesis of cholesterol, steroid hormones and phospholipids
Involved in absorption, synthesis and transport of lipids from the gut
Rough endoplasmic reticulum structure
System of membranes continuous with the nuclear envelope
Contain fluid filled cavities called cisternae
Has ribosomes lying on it surface
Smooth endoplasmic reticulum structure
System of membranes continuous with the nuclear envelope
Fluid filled cavities called cisternae
Does not have ribosomes
Golgi apparatus function
Modification of proteins e.g. adding lipids lipoprotein
Packages proteins into vesicles to travel to different part of the cell or the plasma membrane
Golgi apparatus structure
System of membrane bound flattened sacs
Vesicles bring materials to and from the Golgi
ribosome structure
made of 2 subunits which are joined together in the cytoplasm
Made from RNA
Ribosome function
Protein synthesis
Translates mRNA sequence to form proteins from amino acids
on the RER proteins are mainly from extracellular proteins
in the cytoplasm mainly for intracellular proteins
Nucleolus structure
No membrane surrounding it
Nucleolus function
contains RNA
synthesizes ribosome subunits
Mitochondria structure
Double membrane, inner membrane is continuous with highly folded section called cristae
Filled with fluid matrix
Mitochondria function
Site of aerobic respiration to produce ATP
Can self-replicate if the cell is in need of more energy
Abundant in more metabolically active cells
Lysosome structure
Vesicle containing powerful hydrolytic enzymes
Lysosome function
Separates powerful enzymes from the rest of the cell
Abundant in phagocytes which digest pathogens with the enzymes in lysosomes
Can Digest old organelles and parts can be returned to the cell for re-use
Chloroplast structure
Double membrane inner membrane continuous with flattened membrane sacs called thylakoids, stacks called grana
Fluid matrix called stroma
Contain chlorophyll, starch granules and DNA loops
Chloroplast function
Site of photosynthesis
Plasma membrane structure
made of phospholipid molecules
plasma membrane function
separates the inside of the cell from the external environment
Controls what goes in and out of the cell
Centriole structure
made of 2 microtubule bundles perpendicular to each other
Made of tubulin subunits
Centriole function
Creates spindle fibres in mitosis and meiosis
Creates cilia and undulipodia by lying under the plasma membrane and sprouting tubulin threads
Cell wall structure
Made of cellulose in plants and chitin in fungi
fully permeable
Provides mechanical strength, cell shape,
Flagella structure
protrusion from the cell surrounded by the plasma membrane
formed from centrioles
only seen in sperm in humans
Flagella function
Aid cell movement
Cilia structure
Protrusions from the cell surrounded by the plasma membrane
Contain microtubules
Formed from centrioles
Cilia function
For receptors for cell to detect information about its environment
In ciliated epithelial cells in the lungs to waft mucus out of the lungs
Cytoskeleton role
Mechanical strength, transport within cells
Cell movement
Eukaryote and prokaryote similarities
Plasma membrane
Ribosomes
DNA
RNA
Eukaryote and prokaryotes differences eukaryotes have:
membrane bound organelles (nucleus, mitochondria etc.)
Larger ribosomes (80S)
DNA in chromosomes
DNA around histone proteins
Cellulose cell wall
Eukaryote and prokaryotes differences eukaryotes have:
Naked DNA (no histones
DNA in a loop
Peptidoglycan cell wall
Smaller ribosomes (70S)
some have: pili, capsule, flagella
What microscope has the highest magnification
Transmission electron microscope
Vacuole structure
Surrounded by a membrane called the tonoplast
contains fluid
Vacuole function
Maintains cell stability when full by pushing against cell wall making it turgid
Cytoskeleton structure
microfilaments (actin)
intermediate filaments
microtubules (tubulin)
motor proteins
microfilament function
give support and mechanical strength
stable cell shape
cell movement
Microtubule function
for tracks for motor proteins for movement of substances and organelles
form the spindle
form cilia and undulipodia
help shape and support
Intermediate filament function
anchor the nucleus within the cytoplasm
enable cell signalling
adhere cells to basement membrane, stabilising tissues
