Cell : the unit of life Flashcards
study of cell
cytology
life is a property of interaction.T/F
true.
define cell.
the basic fundamental and functional unit of life.
Who gave the term cellula.Who discovered cell wall and cell which was non living ?
robert hooke
Who gave the term animalcules?
A.V leeuwenhoek
who discovered the first living cell and how?
A.V leeuwenhoek
Who discovered nucleus and in which plant.
Robert Brown, orchid
What were the conclusions by Schleiden and Shwann respectively?
what are these conclusions called ?
Schleiden- German botanist - all the plants are made up of cells
Schwann - British zoologist - all animal cells are covered by membrane i.e plasma membrane.
THE CELL THEORY
What does the cell theory say ?
1) all organisms are made up of cells and its products.
2) All cells arise from pre existing cells “Omnis cellula e cellula”- Rudolf Virchow.
3) Function of an organism is the sum total of the the interactions of its constituent cells.
components of the cell envelope?
- Glycocalyx
- Cell Wall
- Plasma Membrane
Main Dna is part of nucleoid.
True
Components of nucleiod.
- Main dna
- rna
- ribosome
- proteins
What does glycocalyx do and what is it made up of ?
made up of sugar and amino acids helps bac to be adhesive.
Two type of glycocalyx
use of second type
thin - slime layer
thick - capsule (protect the bac from the the immune cells of the host body)
Explain R strain and S strain bac
non virulent as sugar molecule exposed due to slime layer
virulent coz sugar molecule not exposed due to thick capsule
Cell wall is living or non living?
is it selectively/semi/fully permeable?
non living and rigid
fully permeable
what is algal cell wall made up of ?
cellulose, galactans, mannans and minerals like caco3
what and how is the cell wall of plantae and protista made?
polymerisation of glucose w/o any change.
- cellulose
- hemicellulose
- pectin
how is the cell wall of fungus formed
polymarisation of glucose along with the addition of acetyl and amine group.
NAG formed.
polymer of nag = chitin which forms the cell wall
monera cell wall formation
nag+lactic acid = nam
nag+nam+proteins = peptidoglycan (what does it mean?)
what is the cell membrane made up of ? is it selectively or semi permeable?
lipids - 40%
proteins - 52%
carbo - rest
selectively permeable
functions of cell membrane
1) transport of solute and solvent
2) during respiration, photosynthesis and secretion modifies(invegination) itself to increase surface area.
what does the cell membrane develop into?
mesosome and chromatophore
what are the functions of mesosome and chromatophore and what do they contain?
mesosome (contains enzyme) - respiration ,bacterial division , dna seperation during duplication .
chromatophore (contains pigments for photosynthesis)
- helps in photosynthesis
what is mesosome similar to?
what is chromatophore similar to?
- cristae of the mitochondria of eukaryotic cell.
- thylakoi of chloroplast of eukary cell
diff between semi permeable and selectively permeable membrane
- transport of solvent
- transport of solvent plus selected solute
3 types of modified cell wall
lignified - fully permeable
suberized- cant transport any material
cuticularized - cant transport any material
flagella components
- hook
- filament
- basal body
explain the structure of flagella.
what are distal and proximal rings?
refer pg 6
l and p rings in cell wall
s and m rings in cell membrane
what is pilli made up of?
pillus protein
what is parasexual activity?
genetic recombination w/o use of gamete
process of congjugation in bacteria
refer to pg 7
what is fimbrae
spike like structures which help the bac attach to substances
what is plasmid ? what is it made up of and from where does it arise?
extra chromosomal/nucleoid/genetic material.
made of ds dna and made from main dna
types of plasmid and function?
f plasmid - fertility factor r plasmid - resistance factor Col plsmid - colicine - to kill other bacteria Degraditive plasmid refer to pg 8 for more
what are cell inclusions ?
give three examples.
aggregate of non living material of cell.(proteins,oil drops,carbohydrates,lipids)
- Cyanophyccans- carbo in blue green algae
- phosphate granules
- poly-beta-hydroxy butyrate : source for production of bio plastics.
what all things are membraneless in a cell?
,cell inclusions,ribosomes
why are ribosomes called palade particles?
because they were discovered by george palade
what type of ribosomes are there in a plant cell?
70s
what is the function of ribosomes
protein synthesis
In a prokary cell ,what do ribosomes present in the cell membrane do?
they help in the production of extra cellular or secretory proteins that are sent outside the cell.
In a prokary cell, what do the ribosomes present in the cytoplasm do?
they help in the production of the intracellular proteins or non secretory proteins
what is the 70s ribosome made up of?
50s and 30s subunits
what is a polysome?
many ribosomes on 1 m-rna is called a polysome
why do cancer cells have abundance of ribosomes?
they need more proteins to divide rapidly
who saw the cell wall first?
robert hooke
is the cell wall dead or living?
dead coz it lacks regulatory proteins which regulate the transport of materials
what is the cementing agent b/w two cells?
the middle lamella
what is the middle lamella made up of ?
Ca and Mg pectate (calcium plus pectin - glucose derivation)
what happens during ripening of a fruit?
the middle lamella degrades and the cells separate due to which the fruit becomes soft.
what do meristematic cells have and why? (type of cell wall)
primary cell wall coz they are elastic and can grow in young plants, but this ability diminishes as the cell matures.
how is the secondary cell wall formed?
deposition of material inside the primary cell wall by the process of intusuccpetion.
what is desmotubule
help in the regulation of transport of material. such as water, minerals, rna and dna.
what is the plasmodesmata?
why is it called cytoplasmic bridge?
desmotubule + cytoplasm
joins the cytoplasm of two cells.
what is symplast?
the protoplasm continuation is k/a symplast.
what are pits?
loss of protoplasm by the cell leads to formation of lumen and blanks pace. these blank spaces in the plasmodesmata aka PITS.
where are the pits present ?
only in secondary cell wall
- tracheids and vessels of xylem
- sieve tubes of phloem.
types of pits
simple - uniform thickness
bordered - over deposition of cell wall material
functions of cell wall
refer to pg 111
is the cell membrane living?
yes as it has regulatory proteins
what is lipid of cell membrane made up of?
structure?
glycerol + 2 fatty acid + phosphate
head- phosphate - hydrophilic
tail-fatty acid- hydrophobic
what were the various models of cell membrane ?
1) overtan
2) gorter and grandel
3) davson and danielle
4)singer and nicholson
refer pg 12
what did gorter and grandel say?
double the amount of lipids as comapared to the surface area hence called the bilipid layer
thickness of protein and lipid bilayer in davson and danielle model?
protein - 20 armstrong * 2layers
lipid bilayer- 35 armstrong
total - 75 armstrong
why did davson and danielle fail?
couldnt explain how materials went through the membrane
explain the fluid mosaic model
refer pg 13
what are transmembranous proteins?
1) they are present through out the plasma membrane and help in the transport of material.
2) also called intrinsic protein hard to remove
what are peripheral proteins?
present at only one side of the cell membrane and k/a intrinsic proteins and can be easily removed.
what are the functions of cholestrol in the cell membrane?
- heat management prevent the plasma membrane from freezing or melting
- stabilty
what are the two movements of the plasma membrane?
which all enzymes are involved in the only lipid movement?
- 1) the lateral movement - common - shown by both proteins and lipids
2) flip-flop movement - rare - only done by lipid - governed by flipase and flopase
how do transport of molecules take place by the plasma membrane?
- passive- w/o energy
- active - with energy
- bulk - dependent on pressure includes endocytosis (phagocytosis and pinocytosis) and exocytosis(cell vomiting)
what is the endomembrane system?
what all does it include?
endo- inside the cell
membrane - membrane bound organelles
system- work in coordination
THE ER, GOLGI, LYSOSOMES AND VACUOLES
what is the other name for er and why is it called dynamic?
the skeleton of the cell.
coz membranes constantly keep fragmenting and making.
what does the er divide the cell into?
luminal(inside the er) and extra luminal(outsid ethe er) space
what are the components of er?
cisternae
tubule
vesicles
short note on cisternae of er
- flat sac like structures
- helps in protein synthesis so has 80s ribosomes attached
why is the mitochondria called the powerhouse of the cell?
produces atp and helps in its transport as well by taking the help of nadh2 and fadh2
what is the shape of the mitochondria?
cylindrical and sausage shaped
why do we need to stain mitochondria?
which dye is used to dye mitochondria?
because of its small size
janus green
how many membrane does mitochondria have?
name them.
2 membranes. the outer mitochondrial membrane and the inner mitochondrial membrane.
what is the function of outer mitochondrial membrane?
has lipid bilayer and helps in the transport of materials
what is the function of IMM?
why does it have more proteins?
helps in aerobic respiration which helps the electron transport system.
requires high amt of proteins because ets needs it. high amt o fprotein is stored in the cristae and imm and to hold these phospholipids converts into a new form called CARDIOLIPIN
what are oxysomes and where are they?
they are made up of F0 and F1 particles and are embedded in the cristae.
what are the two compartments of the mitohondria.
- outer mitochondrial compartment (inter mitochondrial membranous space)
- inner mitochondrial compartment (matrix)
what all is included in the inner compartment?
it is the gel like substance
1) DNA : ds , circular and has G C (guanine and cytosine) content
2) RNA
3) RIBOSOMES - 70s
4) ENZYMES
what does the matric do?
helps in krebs/tca cycle and link reaction
explain the aerobic reaction in mito
glycolysis- cytoplasm
link formation - matric
tca cycle - matrix
ETS - cristae and imm
what are the functions of the mitochondria?
1) helps in aerobic respiration
2) produces energy and converts it into atp
do plastids need to be dyed?
no as they are large organelles
which all cell organelles have double membrane?
mitochondria, plastids
what are the three types of plastids on the basis of pigments?
1) Leucoplasts - colourless
2) Chromoplasts - coloured
3) Chloroplasts - green coloured
what is the function of leucoplast and what are the three type of luecoplasts ?
luecoplasts helps in the storage of biomolecules.
1) Amyloplast : storage of carbo - eg potato
2) Elioplast : storage of oil - eg castor seed
3) Alueroplast : storage of protein -
eg maize seed - central part - carbo
outer part - has alurone layer where the cells contain aleuroplast
what colour are carotenoids responsible for and what is its relation with water?
yellow red - pink - red
hydrophobic in nature
where are carotenoids present in the cell?
in the membrane of chromoplast
what are anthocyanins? how does it react with water? where are they located?
pigments which give violet color.
hydrophilic
vacuole or cytoplasm
what pigment does chloroplast contain? water relation?position?
chloropyhll
hydrophobic
in the membrane of chloroplast
what all does the stroma include ?
1) gel like structure.
2) thylakoid - group of thylakoid - granum
3) stroma lamella
4) DNA , RNA , 70s ribosome, protein factor
what is the thylokoid?
disc shape structure covered by thylakoid membrane
which all pigments does the thylakoid membrane contain?
CHLOROPHYLL
CAROTENOID
XANTHOPHYLL
what does the stroma lemalla do?
connects two granum
what are ribosomes made up of?
ribonucleic acid and proteins aka r-rna
what is the 70s rna made up of?
30s - 16s plus proteins
50s - 23s + 5s plus proteins
what is 80s rna made up of?
40s- 18s plus proteins
60s- 28s + 5.8s + 5s plus proteins
what is s in 70s and 80s?
it is the sedimentation constant which denote the size and density of the ribosome. it is also k/a swedbergs unit.
what is the largest cell organelle?
in plant cell?
nucleus
vacuole
which all organisms have more than one nucleus ?
PARAMECIUM- two nucleus
one macro for nutrition
one minor for reproduction
OPALINA
permanent multinucleate condn
what all are anucleate?
RBC - matabolism not controlled at maturity and hence a non living object
SIEVE TUBES OF PHLOEM - metabolism controlled by companion cells hence a living being
what all is included in the nuclear envelope?
inner nuclear membrane
outer nuclear membrane
inter nuclear membranous space ka perinuclear space
nuclear pore
describe the inner nuclear membrane
it is smooth
no ribosome
not attached to the er
describe inter nuclear membranous space and how thick it is?
space between the two membranes
20-25nm
describe outer nuclear membrane
it is rough
has 80s ribosomes
connected to er
describe nuclear pore.
highly regulated.
space of attachment of the membranes
what is included in nucleoplasm?
nucleolus and chromatin material
what are chromatin and what dye is used to stain it?
chromatin are coloured components
ACETOCARMINE
what all does chromatin material have?
- dna
- rna
- enzyme factor
- histone and non histone proteins
what are the two colour patterns of dyed chromatin
- heterochromatin
- euchromatin
what is heterochromatin and what does it do?
what is it also called?
it has more colour. Rna synthesis doesnt take place here because the dna here is densely packed.so it is genetically not active
it is aka junk dna
what is euchromatin?
less color
rna synthesis takes place as the dna is loosely packed here
genetically active
what does the nucleolus do?
it is teh active site oof the production of ribosomes by combining the ribosomal subunits and the proteins.
what is cytoskeleton?
filamentous proteinaceous structure made up of microfilaments , microtubules and intermediate filaments.
function of cytoskeleton
- mechanical support
- maintains shape
- motility
- condensation of dna
cilla are small structures which work like ___
oars
what is microtubule?
tubule at micron or very small level.
structure of microtubule
monomers- alpha and beta tubulin proteins —> polymerization —-> protofilament —-> 13 protofilament = 1 microtubule
size of microtubule
25nm and hollow structure - 15nm and protofilament size - 10nm
functions of microtubule ?
- shape of cell
- formation of cilia and flagella
- formation of centriole,spindle fibres,spindle appendages and astral rays
which all cell organelles are membrane less?
centriole and ribosomes
how are two centrioles arranged and what is their combination called?
arranged at 90 degree to each other
-diplosome or centersome
which cell organnelle is present in eukary cells but not in higher plants ?
centrosome
