Unit 1: Prokaryotes and Eukaryotes Flashcards
Name a method than can be used to increase the amount of detail seen in a cell with a light microscope.
Staining
What is the difference between light microscopy and electron microscopy?
The power of the electron microscope is greater than of the light microscope due to the shorter wavelengths of electrons compared to visible light. Electron microscope is much clearer. Electron microscope has greater resolving powers so that the internal structure of the cells can be studied more clearly.
what is the range in size for a prokaryote and a eukaryote?
Prokaryote - 1 micrometers to 10 micrometers
Eukaryote - 10 micrometers to 100 micrometers
In what way does the surface area to volume ratio impose limit on cell size?
There is an upper limit to the surface area to volume ratio because of the rate of oxygen diffusion. Oxygen is required by the cell for respiration. Other nutrients must also enter the cell and waste material - (CO2) must leave the cell.
What are Cells?
The basic unit of life
List the structures of a prokaryote.
Plasmid, Ribosomes, Plasma membrane, Bacterial cell wall, flagella, pili, mucilaginous capsule, cytosol, single circular DNA - nucleoid
How do Prokaryotic cells divide?
By binary fission
What is the bacterial cell wall made up of?
Peptidoglycan
What is the main method to classify bacteria?
Gram’s stain
Gram stains - what difference is used to distinguish the bacteria?
The levels of peptidoglycan present in the cell wall
Name the three different shapes of bacteria
spherical - cocci
rod-like - bacilli
spiral - vibrios
What is the function of the mucilaginous capsule?
for adherence and protection
What is the function of the pili?
for anchoring - to help attach the cell to surfaces
What is the function of the flagella?
used for motility
What is the function of the bacterial cell wall?
to maintain cell shape, protects the cell and prevents excessive uptake of water
What is the function of the cytosol?
the site of cell metabolism
What is a nucleoid?
Highly condensed single circular DNA molecules
What is the function of ribosomes?
The site of protein synthesis
What are plasmids?
additional rings of DNA in the cytosol
What are endospores?
they are highly resistant to external changes
What are cysts?
they are resistant to desiccation but not at high temperatures
List the structure of Eukaryotes
Rough endoplasmic reticulum, nucleus, nuclear pore, plasma membrane, nucleolus, nuclear membrane, chromatin, ribosomes, smooth endoplasmic reticulum, cilia, golgi apparatus, microtubules, centrioles, lysosomes, mitochondria, microfilaments
what is a nuclear membrane
has a double membrane with pores to let very large molecules pass through
what is the function of a nucleolus
in the nucleus and is where RNA is transcribed
Name the structure of the mitochondria
has a double membrane, matrix and cristae of the mitochondria
what is the purpose of the cristae of the mitochondria?
presents a large surface area on which respiratory processes can take place.
Where are the enzymes in the mitochondria
in the matrix of the mitochondria
what are nucleosomes?
has genetic linear material organised as chromosomes. The DNA is wrapped around histone proteins to form a nucleosome
what is the function of a lysosome?
contains enzymes to digest and recycle parts of the cell
what is the function of microvilli?
increase the surface are for absorption
what is the function of the cytoskeleton?
maintains cell shape, arranges organelles
What is the cytoskeleton made up of?
actin filaments, intermediate filaments, and microtubules
what are actin filaments made up of?
actin - a globular protein
What are microfilaments?
two chains twisted into a helix
what are actin filaments important for?
contractile apparatus for muscle cells, cell division and maintenance of cell shape
what are the functions of intermediate filaments?
strength in the cell mechanically and helps prevent cells from rupturing
what are microtubules made of?
tubulin
what is the function of microtubules?
used to help cells divide and to form cell projections e.g. cilia or flagella
List the organelles only found in plant cells?
central vacuole, plant cell wall, plasmodesmata, middle lamella and chloroplast
Name the structures of the chloroplast
double membrane, stroma, granum
what is the function of grana in the chloroplast?
contain photosynthetic pigments as it is the site of the light-dependent stage in photolysis
what are lamella in the chloroplast?
tubular extensions which form an interconnecting network between grana
what is the function of the stroma?
site of carbon fixation
what are plasmodesmata?
cytoplasmic links between neighbouring cells present in cell walls
what are the middle lamella composed of and what is their function?
pectin and glue neighbouring cells together at cell wall
what is the central vacuole?
stores sugars, ions and pigments and is important in keeping the turgidity of the cell.
what are the similarities of eukaryotes and prokaryotes?
both contain nucleic acids, proteins, carbohydrates and lipids
both use same kind of reactions for storing energy
what are the differences between eukaryotes and prokaryotes?
Prokaryotes have no membrane nucleus or organelles whereas eukaryotic cells have a membrane bound nucleus and membrane bound organelles.
Cell walls of prokaryotic cells are made up of peptidoglycan whereas the cell wall of a plant are made up of cellulose fibres
prokaryotic cell range from 0.5 micro to 10 micro whereas eukaryotic is 10 to 100 micro
Describe the organisation of genetic material in prokaryotes and eukaryotes.
Prokaryotes have single circular DNA molecules. The DNA is condensed to form a nucleoid.
Eukaryotes have a nuclear membrane and the DNA are organised in chromosomes associated with histones to form nucleosome. Plasmids are additional rings of DNA present in prokaryotes
