type of microscopes and what they produce
- produce micrographs
1) light microscope:
- magnify up to 1000x
- coloured images
- 2D
2) electron microscope:
- magnify more than 200000x
- black and white
magnification definition
number of times the image of an object is larger than its actual size
magnification, image, actual size formula
image/actual size x magnification
eg: image measures 50mm on the paper and is 5μm in real life, convert size of image to μm (1mm = 1000μm)
50mm = 50000μm
50000/5
= x10000
the cell is
- fundamental building block, basic structural unit of all living organisms
- smallest unit of life and perform important physiological functions
- come from division of pre-existing cells
types of cells (2)
- prokaryotic cell (bacteria)
- eukaryotic cell (fungi, plants animals)
diff between prokaryotic and eukaryotic cells
size:
p= 1-5μm
e= 10-100μm
type of nucleus
p= no true nucleus
e= true nucleus with double membrane
protein synthesis
p= coupled in cytoplasm
e= RNA synthesis in nucleus
protein synthesis in cytoplasm
mitochondria
p= none
e= 1-1000s
animal cell vs plant cell vs bacteria cell
cell shape:
a: spherical
p: rectangular
b: rod/spherical/spiral
cell type:
a: usually multicellular
p: usually multicellular
b: usually unicellular
true membrane
a: present
p: present
b: absent
number of chromosomes
a: more than one
p: more than one
b: one main with plasmids
endoplasmic reticulum
a: present
p: present
b: absent
mitochondria:
a+p: present
b: absent
golgi apparatus:
a+p: present
b: absent
plasma membrane
- forms physical boundary between cytoplasm of cell and external environment
- selectively permeable
- membranes found enclosing organelles
- provides enough SA for absorption of nutrients and disposal of wastes
- provides shape and protection
cell wall
- encoloses the entire plant cell
- made of cellulose
- fully permeable
- gives shape and structure
cytoplasm
- in eukaryotic cell: site where most cellular reactions occur
- aqueous medium that contains many dissolved substances and enzymes
- contains many organelles
cytoskeleton
- provides structural scaffolding to maintain cell shape
- anchors proteins in the plasma membrane
- facilitate movements of vesicles and other biomolecules
nucleus
- surrounded by membrane called nuclear membrane
- contains genetic information in chromosomes
- controls cell activities (cell growth, repair of worn-out parts)
- essential for cell division
- produces mRna important for protein synthesis
- nuclear pores facilitate transport of materials in and out of the nucleus
- largest organelle
chromatin
- composed of proteins and DNA
- DNA contains all genetic information that are essetnail for the survival of the cell
- when cell is dividing, chromatin condenses into more tightly coiled structure (chromosome)
nucleolus
- dense spherical body within the nucleus, made of ribosomal RNA
- responsible for synthesis of ribosomes -> essential for protein synthesis and assembly
endoplasmic reticulum
- extensive network of membrane
- er membrane is continuous with outer membrane of nucleus
rough endoplasmic reticulum
- flattened sheets/sacs
- abundant in cells that secrete proteins/growing rapidly
- appears rough
- ensure proper folding of proteins, synthesises enzymes, manufactures various protiens
ribosomes
- small round structures
- attached to rer of lie freely in the cytoplasm
- needed to synthesise proteins in the cell
- attach to rer to make protiens that are transported out of the cell
- rer transport prtoeins made by ribosomes through vesicles to golgi body
- if attached to rer- proteins made are transported out
- if free, use in cell
smooth er
- turbular to increase surface area
- abundant in cells that secrete steroid/lipids
- involved in synthesis of lipids, phospholipids, steroids
- drug detoxification
- Involved in attachment of receptors on cell membrane proteins.
golgi apparatus + vesicels
- flattened sacs, but not physically connected
- vesicles are concentrated in the vicinity of golgi apparatus
-> transfer material between parts of golgi and others - modification of biomolecules
- modifies, sorts, pacakges proteins/lipids into secretory vesicles for cell secretion/use within cell
vesicles:
- move material from er to golg, fuses into golgi through cis face
- pinch off from from trans face
substances out of er to golgi app process
- vesicles transports substances within cells
-> vesicle containing substances made by ER pinches of
-> these besicles fuse with the golgi app and release contents in to golgi app
-> substances are modifidied in the golgi and is package into secretory veiscles that are excreted
mitochondrion
- bound by double membrane
- site of aerobic respiration where adenosine triphophate is produced to power various cellular activities
- mitchondria is the powerhouse of cell
- numerous present in cells with high energy requirements
- rod sausage shape structure
(- inside has large sa for enhancing productivity of cellular respiartion)
chloroplast
- contains green pigment, chlorophyll
- bound by double membrane
vacuole
- contains mostly water
- plant cells have large central vacoule in middle of cell (contains cell sap which contains sugar, mineral salts, amino acids)used for osmotic control and nutrient storage
- partially permeable membrane
- surrounded by membrane known as tonoplastd
double bounded membrane (3)
- nucleus
- mitochondria
- chloroplast
