1. Cell Structure Flashcards
What is the function of microvilli?
increase the surface area of the cell surface membrane for more efficient absorption or secretion
Draw and label a chloroplast (8 labels)
thylakoids containing chlorophyll which are called grana when stacked, small circular DNA, double membrane, stroma, 70s ribosomes, enzymes for photosynthesis, starch grains
What is different about the cell wall of bacteria?
it is made up of murein/peptidoglycan instead of cellulose
What is the function and structure (3) of the cell wall?
function: provides support and protection
structure:
1) the cell is not an organelle
2) it is made of cellulose and is fully permeable (water can be lost through them)
3) it has small holes (plasmodesma)
What is the function and structure of the SER?
function: produces and stores lipids, steroids and hormones
structure: has tubular strucutres
What is the function and structure of the golgi apparatus?
function: modifies and packages proteins from the endoplasmic reticulums
structure: has flattened sacs called cisternae
What is the function and structure of pili?
function: allows bacterium to stick to one another
structure: made of proteins
Draw and label a bacteria (10 labels)
cell wall, cell surface membrane, cytoplasm, circular DNA, plasmid, pili, 70s ribosomes, infolding of cell surface membrane, slime capsule, flagellum
A micrometre is 1x10^?
4
A millimetre is 1x10^?
1
What is the function (3) and structure (3) of the large permanent vacuole?
function:
1) isolates harmful materials
2) maintains cell turgidity
3) pushes chloroplasts to the edge to ensure maximum exposure to sunlight
structure:
1) filled with water containing inorganic and organic molecules, enzymes
2) membrane of vacuole known as tonoplast
3) formed from fusion of vesicles
Higher resolution?
greater DETAIL
What is the function of the ribosome?
site of protein synthesis
What is the function and structure of the flagella in prokaryotes?
function: allows the bacterium to move forward in a corkscrew motion
structure: made of proteins, rigid structure so it does not bend like flagella in eukaryotes
What is the structure and function of the lysosome?
structure:
1) contains digestive enzymes (such as proteases, lipases and nucleases) called hydrolase, which carries out hydrolysis reactions
2) acidic contents for optimum environment of enzymes
function:
enzymes are synthesized on RER and the golgi apparatus delivers them to lysosomes
responsible for the breakdown of unwanted substances and structures
What is the function and structure of the slime capsule?
function: protects the bacteria from drying out
structure: capsule made of mucilaginous slime
What is the middle lamella?
a layer that cements together the primary cell walls of 2 adjoining plant cells
5 disadvantages of electron microscopes
1) specimens must be dehydrated, so only dead specimens can be examined
2) requires a machine (ultramicrotome) that slices the specimen to ensure its really thin; time consuming and not cost effective
3) dull blades on the ultramicrotome can disturb organelles and create artefacts
4) expensive
5) immobile
What is the function of the nucleus?
contains genetic material and controls cell activities
What is the function and structure of the centriole?
function: organises microtubules, that pull chromosomes apart in mitosis
structure: barrel shaped organelles in the cytoplasm of animal cells
What is the maximum resolution and magnification of a light microscope?
res.: 200nm
mag.: x1500
What is the function of the cell membrane?
controls what goes in and out of the cell
Draw and label a plant cell (20 labels)
cell wall, cell membrane, large permanent vacuole, tonoplast, cytoplasm, chloroplast, plasmodesmata, 80s ribosomes, 70s ribosomes in the chloroplast, starch granules
What is in the cytoplasm of bacterial cells (3)?
70s ribosomes, glycogen granules and oil droplets
What is the function of cytoplasm?
- maintains cell shape and structure
- allows transport within the cell
- provides cell protection
- acts as storage and a site for metabolic processes
What is the function of chromatin?
consists of DNA, proteins, and RNA
used to make chromosomes
What is the function and structure (4) of the RER?
function: protein synthesis
structure:
1) has flattened sacs called cisternae
2) cisternae is lined with 80s ribosomes
3) it lies adjacent to the nucleus
4) its membrane is continuous with the nuclear envelope
What are prokaryotes and eukaryotes?
prokaryote:
- lacks nucleus and other organelles
- unicellular
- includes bacteria
eukaryote:
- multi-celled organism
- animal and plant cells
What is the function of vesicles?
transport molecules, secrete substances, digest materials, or regulate the pressure in the cell
What are plasmodesmata/plasmodesma?
small holes in the cell wall that allows nutrients, ions and waste to pass through
What is the function and structure of the mitochondria?
function: breaks down glucose into ATP, produces energy through cellular respiration
structure: has flattened sacs called cristae
What is the nuclear envelope?
2 lipid bilayer membranes that provide structure and separate the contents of the nucleus from the cytoplasm
The infolding of the cell surface membrane is to create extra surface for which 2 reactions to take place?
extra surface area for the attachment of enzymes for respiration
1) biochemical reactions
2) nitrogen fixation – converts nitrogen in the air to nitrogen containing compounds (e.g ammonia) inside the cell
What is a stage micrometer?
a mini, transparent ruler engraved on a microscope slide that can be placed on the microscope stage to calibrate the eyepiece graticule
What is the maximum resolution and magnification of an electron microscope?
res.: 0.5nm
mag.: x500,000
What is the function of plasmid?
function: contains genes that provide resistance to antibiotics (e.g pencillin)
Draw and label an animal cell (16 labels)
nucleus (nucleolus, nuclear envelope, chromatin), cytoplasm, cell membrane, lysosome, mitochondria, 80s ribosomes, 70s ribosomes in the mitochondria, centriole, golgi apparatus, RER and SER, vesicles, microvilli
2 advantages of electron microscopes
1) metal stains can be added to highlight key structures
2) the images always come out on computer, so false colour can be added
What is the diameter of chloroplast?
5 micrometers
A nanometre is 1x10^?
7
What is the difference between transmission and scanning electron microscopes?
transmission: produces 2D images
scanning: produces 3D images
What is resolution?
the ability to distinguish between 2 separate objects that are very close together
What is an eyepiece graticule?
a small, transparent scale of 100 divisions that can be placed in a microscope eyepiece to measure cells and organelles
What is the function of the nucleolus?
manufactures ribosomes, which are made up of ribosomal proteins and rRNA (ribosomal RNA)
What is a hydrolysis reaction?
addition of water to break down a covalent bond
