Cell Flashcards
First cell discovered by ____ in ____
Robert hooke, Cork cells- Quercus suber
Father of microbiology
Anton van luewanhoek
1st living cell discovered (bacteria) but- called it Animalcules
_____ named animalcules bacteria
Ehrenburg
Robert brown discovered
nucleus
schleiden proposed that
All plants are composed of different kind of cells which form the plant tissue
It is the —- that emphasised the unity underlying this diversity of forms, i.e., the cellular organisation of all life forms.
cell theory
Cell theory also created a sense of mystery around living phenomena, i.e., —-and —- processes. This mystery was the requirement of —- of cellular organisation for living phenomena to be demonstrated or observed.
physiological and behavioral
integrity
In studying and
understanding the physiological and behavioural processes, one can take a —- approach and use — systems to investigate. This approach enables us to describe the various processes in —- terms.
physico-chemical
cell-free
molecular
The approach is established by analysis of — for elements and compounds. It will tell us what types of organic
compounds are present in living organisms.
living tissues
In the next stage, we answer the question, what is the —- of all physiological processes?
It can also explain the —processes that occur during any diseased condition.
molecular basis
abnormal
This physico-chemical approach to study and
understand living organisms is called —-. The concepts and techniques of physics and chemistry are applied to
understand biology.
‘Reductionist Biology’
When you look around, you see both — and —things.
living and non-living
what is it that an inanimate thing does not have which a living thing has?
presence of the basic unit of life – the cell in all living organisms.
All —- are composed of cells. Some are composed of a single cell and are called —organisms while others, like us, composed
of many cells, are called —organisms.
organisms
unicellular, multicellular
Unicellular organisms are capable of (i)—- and
(ii) —-.
-independent existence
-performing the essential functions of life
Anything less than a —–does not ensure independent living. Hence, cell is the — structural and functional unit of all living organisms.
complete structure of a cell
fundamental
The invention of the microscope and its improvement leading to the —- revealed all the
structural details of the cell.
electron microscope
In —-, Matthias Schleiden, a —–, examined a large number of plants and observed that all plants —- which form the tissues of the plant.
1838, German botanist
are composed of different kinds of cells
At about the same time, Theodore Schwann (—), —-, studied different types of animal cells and reported that ——.
1839, a British Zoologist
cells had a thin outer layer which is today known as the‘plasma membrane’
—- also concluded, based on his studies on plant
tissues, that the — is a unique character of the plant cells.
Schwann, presence of cell wall
On the basis of this, —-proposed the hypothesis that the bodies of animals and plants are composed of cells and —-
Schwann
products of cells.
Schleiden and Schwann together formulated the —-.
cell theory
The cell theory however, did not explain as to —-.
how new cells were formed
Rudolf Virchow (—) first explained that cells divided and new cells are formed from pre-existing cells (—-).
1855, Omnis cellula-e cellula
—- modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape.
Rudolf Virchow
Cell theory as understood today is:
(i) all living organisms are composed of cells and products of cells.
(ii) all cells arise from pre-existing cells.
The onion cell which is a typical plant cell, has a — as its outer boundary
and just within it is the cell membrane.
distinct cell wall,
The cells of the human cheek have an outer membrane as the —structure of the cell.
delimiting
Inside each cell is a —membrane bound structure called nucleus.
dense
This nucleus contains the chromosomes which in turn contain the —-, DNA.
genetic material
Cells that have membrane bound nuclei are called
— whereas cells that lack a membrane bound nucleus are prokaryotic.
eukaryotic
In both prokaryotic and eukaryotic cells, a — matrix called cytoplasm occupies the volume of the cell. The cytoplasm is the main—- in both the plant and animal cells. Various chemical reactions occur in it to keep the cell in the —–
semi-fluid,
arena of cellular activities
‘living state’
Besides the nucleus, the —- cells have other membrane bound
distinct structures called organelles like the endoplasmic reticulum (ER), the golgi complex, lysosomes, mitochondria, microbodies and vacuoles. The prokaryotic cells lack such —-.
eukaryotic
membrane bound organelles
Ribosomes are —- found in all cells – both eukaryotic as well as prokaryotic.
non-membrane bound organelles
two
chloroplasts (in plants) and mitochondria and on rough ER.
Animal cells contain another non-membrane bound organelle called
centriole which helps in —.
cell division
Schwann and schleiden claimed origin of cell to be
Denovo- Spontaneous
Omni cellula e cellula followed by all cells except
RBCs (formed in bone marrow)
Virus
Neurons
Rhizopus
Cells differ greatly in —,—- and—-
shape, size and activities
—, the smallest cells, are only — in length
Mycoplasmas, 0.3 µm
Bacteria size could be —.
3 to 5 µm
The largest isolated single cell is the —-.
egg of an ostrich
Among multicellular organisms, human red blood cells are about —-.
7.0 µm in diameter
Nerve cells are some of the — cells.
longest
Cells also vary greatly in their shape. They may be —like, polygonal, columnar, cuboid,
—-, or even irregular. The shape of the cell may vary with the
——
disc, thread like,
function they perform
Animal cell and plant cell size
10-20 um
30-50um
round and oval cells are
mesophyll cells
a trachied is — shaped
spindle, elongated
The prokaryotic cells are represented by bacteria, blue-green algae, mycoplasma and—-.
PPLO (Pleuro Pneumonia Like Organisms)
Prokaryotic cells are generally — and multiply more rapidly than the eukaryotic cells
smaller
The prokaryotic cells may vary greatly in — and —.
shape and size
The four basic shapes of bacteria are — (rod like), coccus (spherical), vibrio (—shaped) and spirillum (spiral).
bacillus, comma
The organisation of the prokaryotic cell is —- even though prokaryotes exhibit a wide variety of shapes and functions. All
fundamentally similar
All prokaryotes have a cell wall surrounding the
cell membrane except in —.
mycoplasma
There is no — nucleus. The genetic material is
basically naked, not enveloped by a —
membrane.
well-defined
nuclear
In addition to the — DNA (the single chromosome / — DNA), many
bacteria have small circular DNA outside the
genomic DNA. These smaller DNA are called
—.
genomic, circular
plasmids
The plasmid DNA confers certain unique — characters to such bacteria. One such character is —-
phenotypic
resistance to antibiotics.
This plasmid DNA is used to monitor —- with foreign DNA.
bacterial transformation
No organelles, like the ones in eukaryotes, are found in prokaryotic cells except for —-.
ribosomes
Prokaryotes have something unique in the form of —.
inclusions
A specialised differentiated form of cell membrane called mesosome is the —-
of prokaryotes. They are essentially —- of cell membrane.
characteristic
infoldings
Most prokaryotic cells, particularly the — cells, have a chemically
complex —–.
bacterial, cell envelope
The cell envelope consists of a— three
layered structure i.e., the outermost — followed by the —- and then the plasma membrane.
tightly bound
glycocalyx , cell wall
Although each layer of the cell envelope in bacteria performs distinct function, they act together as a single —- unit.
protective unit
Bacteria can be classified into two groups on the basis of the differences in the —- and the manner in which they respond to the staining procedure developed by — viz., those that take up the gram stain are — and the
others that do not are called Gram negative bacteria.
cell envelopes, Gram
Gram positive
Glycocalyx differs in — and — among different
bacteria. It could be a loose sheath called the —- in some, while in others it may be —-, called the capsule.
composition and thickness
slime layer, thick and tough
The — determines the shape of the cell and provides a strong structural support
to prevent the bacterium from — or collapsing.
cell wall \, bursting
The plasma membrane is semi-permeable in nature and interacts with —-. This membrane is similar structurally to that of the
eukaryotes.
the outside world
A special — structure is the mesosome which is formed by the extensions of plasma membrane into the cell. These extensions are in the form of —,—-and—.
membranous
vesicles, tubules and lamellae
Mesosomes help in —formation, —- and distribution to daughter cells, —-, secretion processes, to increase the surface area of the plasma membrane and — content.
cell wall, DNA replication
respiration, enzymatic
In some prokaryotes like
—-, there are other membranous extensions into the cytoplasm
called chromatophores which contain —-.
cyanobacteria, pigments
Bacterial cells may be motile or non-motile. If motile, they have — extensions from their cell wall called flagella.
thin filamentous
Bacteria show a range in the — and — of flagella.
number and arrangement
Bacterial flagellum is
composed of three parts – —-, — and —-.
filament, hook and basal body
The — is the longest portion of flagella and extends from the cell surface to the outside.
filament
Besides flagella, — and — are also surface structures of the bacteria but do not play a role in —.
Pili and Fimbriae
motility
The pili are elongated — structures made of a special protein. The fimbriae are small —-sprouting out of the cell.
tubular
bristle like fibres
In some bacteria, — are known to help attach the bacteria to rocks in streams and also to the —tissues.
Fimbriae, host
Glycocalyx layer is made of
Complex polysaccharides
____ causes human diseases
Glycocalyx (GC also helps prevent desiccation- loss of water)
___ enzyme can remove GC layer to form —- form bacteria
Lysozyme, Lister/L
Bac cell wall made of
Murin/Peptidoglycon
(Polysaccharides + AA)
Double layer —- is present in gram -ve bac
Cell wall
Bac are stained by —- for gram procedure
Crystal violet soln
____ is analogous to mito and lysosome respectively
mesosome
periplasmic space
nucleoid in prokaryo is also called
genophore
In prokaryotes, ribosomes are associated with the — of the cell.
plasma membrane
Prokaryotic ribosomes are about —- in size and are made of two subunits - — and – units which when present together form 70S prokaryotic ribosomes.
15 nm by 20 nm
50S and 30S
Ribosomes are the site of — synthesis. Several
ribosomes may attach to a single — and form a chain called polyribosomes or —.
protein, mRNA
polysome
The ribosomes of a polysome translate the
mRNA into —.
proteins
— in prokaryotic cells are stored in the cytoplasm in the form of inclusion bodies. These are not bound by any membrane system and — in the cytoplasm,
Reserve material
lie free
Ex of inclusion bodies of prokaryos —,— and—
phosphate, cyanophycean and glycogen granules (Valutin also wrt notes)
Gas vacuoles are found in —-, —– n—– bacteria.
blue green,
purple and green photosynthetic
____ in PM of prokaryos provide stability
Hapanoides
The eukaryotes include all the protists, plants, animals and fungi. In
eukaryotic cells there is an extensive —- of cytoplasm through the presence of membrane bound organelles.
compartmentalisation
Eukaryotic cells possess an — nucleus with a nuclear envelope. In addition, eukaryotic cells have a variety of complex — and — structures.
organised
locomotory and cytoskeletal
Genetic material of eukaryo is organised into —.
chromosomes
All eukaryotic cells are not —.
Plant and animal cells are different as the former possess cell walls, — and a —- vacuole which
are absent in animal cells. On the other hand, animal cells have centrioles which are absent in —– plant cells
identical
plastids, large central
almost all
The detailed structure of thecell membrane was studied only after the — of the electron microscope in the —s.
advent, 1950
Meanwhile, chemical studies on the cell membrane, especially in human —–, enabled
the scientists to deduce the possible structure of plasma membrane.
red blood cells (RBCs)
The studies of RBC’s showed that the cell membrane is composed of lipids that are arranged in a —. Also, the lipids are arranged within the
membrane with the —- towards the outer sides and the — towards the inner part.
bilayer
polar head, hydrophobic tails
This ensures that the nonpolar tail of —-hydrocarbons is protected from the —environment
saturated, aqueous
The lipid component of the membrane mainly consists of —–.
phosphoglycerides
Later, —- clearly revealed that the cell membranes also possess protein and carbohydrate.
biochemical investigation
The ratio of protein and lipid —- in different cell types.
varies considerably
In human beings, the membrane of the
erythrocyte has approximately—- per cent protein and — per cent lipids.
52, 40
Depending on the ease of extraction, membrane proteins can be
classified as — or —.
integral or peripheral
Peripheral proteins lie on the surface of membrane while the integral proteins are —- buried in
the membrane.
partially or totally
An improved model of the structure of cell membrane was proposed
by —– and — (—) widely accepted as fluid mosaic model
Singer and Nicolson- 1972
According to this, the quasi-fluid nature of lipid enables — movement of proteins within the overall bilayer. This ability to move within the membrane is measured as its —-.
lateral, fluidity
The fluid nature of the membrane is also important from the point of view of functions like cell growth, formation of —-, —, endocytosis, cell division etc
intercellular junctions, secretion
One of the most important functions of the plasma membrane is the —– across it. The membrane is selectively permeable to some molecules present on — side of it.
transport of the molecules
either side
Many molecules can move briefly across the membrane without any requirement of energy and this is called the —transport.
passive
—- solutes may move across the membrane by the process of simple diffusion along the concentration gradient, i.e., from — concentration
Neutral
higher to lower
Water may also move
across this membrane from higher to lower concentration. Movement of water by diffusion is called —.
osmosis
As the — molecules cannot pass through the nonpolar lipid bilayer, they require a —— to facilitate their transport across the membrane.
polar, carrier protein of the
membrane
A few ions or molecules are transported across the membrane against their —- gradient, i.e., from lower to the higher concentration. Such
a transport is an —- process, in which ATP is utilised and is called active transport, e.g., ——
concentration
energy dependent
Na+/K+ Pump.
A —-, —- structure called the cell wall forms
an outer covering for the plasma membrane of fungi and plants.
non-living rigid
Cell wall gives shape to the cell and protects the cell from —- damage and —. It also helps in —- and provides barrier to undesirable —.
mechanical, infection
cell-to-cell interaction
macromolecules
Algae have cell wall, made of cellulose, —-, —and minerals like —-, while in other plants it consists of cellulose, hemicellulose, —-and —–.
galactans, mannans,
calcium carbonate
pectins, proteins
The cell wall of a young plant cell, the —– is capable of growth,
which gradually diminishes as the cell matures and the secondary wall is formed on the —- side of the cell.
primary wall
inner (towards membrane)
The middle lamella is a layer mainly of —- which holds or glues the different neighbouring cells together.
calcium pectate
The cell wall and middle
lamellae may be traversed by —- which connect the —- of neighbouring cells.
plasmodesmata, cytoplasm
Electron microscope discovered by
Knoll and rusca
Trilamellar model was given by
Damielle and davson
Trilamellar model is seen in
Mycoplasma
75 armstrongs in height (Protien in both sides, lipid bilayer in centre.. but doesnt explain selective permeability)
Sugars on PM are called
Oligosaccharides- made of glycoprotein and glycolipid
(helps in cell recognition)
____ in eukaryo Pm gives stability
cholestrol
____ provides fluidity to PM
Phospholipids- rich in unsat fatty acids
___ proteins help in enzymatic activity
Extrinsic/peripheral
ER tubules ===? help in connection b/w cell as it passes thro plasmodesmata
desmotubules
Secondary cell wall made of
Ergastic substance deposition- Pectin with lignin, suberin or cutin
____ have tertiary cw
Gymno
While each of the membranous organelles is distinct in terms of its
structure and function, many of these are considered together as an —- system because —-.
endomembrane, their functions are coordinated
The endomembrane system include —, —, — and —
endoplasmic reticulum (ER), golgi complex, lysosomes and vacuoles.
Since the functions of the mitochondria, chloroplast and —- are not coordinated with the above components, these are not considered as part oft he endomembrane system
peroxisomes
Protoplast==
PM+Cyto
Protoplasm==
Cyto+Nucleus
Tropoplasm (cell organelles) has non living inclusions called —
Duetoplasm
Electron microscopic studies of eukaryotic cells
reveal the presence of a network or reticulum of
tiny tubular structures scattered in the cytoplasm that is called the —-
endoplasmic reticulum (ER)
Hence, ER divides the intracellular space into two distinct compartments, i.e., —-(inside ER) and —(cytoplasm)
compartments.
luminal , extra luminal
ER is abundantly found in
Pancreas and Liver- RER
Muscles- SER
The ER often shows —attached to their outer surface.
ribosomes
The endoplasmic reticulum bearing ribosomes on their surface is called rough
endoplasmic reticulum (RER). In the absence of
ribosomes they appear — and are called
smooth endoplasmic reticulum (SER).
smooth
RER is frequently observed in the cells actively involved in — synthesis and secretion.
protein
The ____ are extensive and continuous with the outer membrane of the nucleus
Rough ER
The smooth endoplasmic reticulum is the major
site for synthesis of —.
lipid
In animal cells —-hormones are synthesised in SER.
lipid-like
steroidal
Camillo Golgi (—) first observed densely stained
— structures near the nucleus. These were
later named — after him.
1898, reticular
Golgi bodies
Golgi body consist
of many flat, —shaped sacs or cisternae of
—- diameter
disc, 0.5µm to 1.0µm
Cisternae of golgi are
stacked — to each other. Varied number of
cisternae are present in a Golgi complex.
parallel
The Golgi cisternae are concentrically arranged near the nucleus with distinct —- or the forming face and — or the maturing face
convex cis
concave trans
The cis and the trans faces of the organelle are entirely different, but
—-.
interconnected
The golgi apparatus principally performs the function of —– to be delivered either to the intra-cellular targets or secreted outside the cell.
packaging materials,
Materials to be packaged in the form of —- from the ER fuse with the — face of the golgi apparatus and move towards the maturing face. This explains, why the golgi apparatus remains in close association with the —-.
vesicles, cis
endoplasmic reticulum
A number of proteins
synthesised by ribosomes on the endoplasmic reticulum are —- in the cisternae of the golgi apparatus before they are released from its
trans face.
modified
Golgi apparatus is the important site of formation of
—- and —-
glycoproteins (glycosilation) and glycolipids (glycosidation).
Hence- forms PM
RER has more cisternae
True
SER has more tubules
Ribosomes attached to rer are —- with help of
60s
ribophorin 1 and 2
____ synthesize precursors of hydrolytic enzymes
RER
___ help in detoxification of drugs
SER
Space around golgi is called
Zone of exclusion
Formation of acrosomes in sperms by
Golgi
formation of lysosomes and middle lamella by
golgi
golgi secretes — in root tips
lubricants
—- are membrane bound — structures formed by the process of packaging in the golgi apparatus.
Lysosomes, vesicular,
The isolated lysosomal vesicles have been found to be very rich in almost all types of —- enzymes (––, —, —, —-) optimally
active at the acidic pH (5).
hydrolytic
hydrolases, lipases, proteases, carbohydrases +nucleases (wrt notes)
The hydrolytic enzymes are capable of digesting
carbohydrates, proteins, lipids and —-
nucleic acids.
____ are the suicidal bags of the cells
Lysosomes
The —- is the membrane-bound space found in the cytoplasm.
vacuole
Vacuole contains
water, —, — and other materials not useful for the cell.
sap, excretory product
The vacuole is bound by a single membrane called —.
tonoplast
In plant cells the
vacuoles can occupy up to —per cent of the volume of the cell.
90
In plants, the tonoplast facilitates the transport of a number of —
and other materials against concentration gradients into the vacuole, hence their concentration is significantly —- in the vacuole than in the
cytoplasm.
ions, higher
In Amoeba the — vacuole is important for excretion. In many cells, as in protists, —vacuoles are formed by engulfing the food particles.
contractile, food
membrane of lysosome has ____ to maintain acidic ph
H+ pump
pleomorphic organelle is
lysosome
prim lysosome===?
storage granules- no active enzyme
secondary lysosome?
fuses with pino/phagosome
==HETEROPHAGOSOME
____ enzyme in lysosome digests tadpoles tail
Cathepsin
Digestion of foreign particles, old cell organelle, extra bone growth by lysosome are each called
heterophagy, autophagy, osteoclast
destruction of cell by lysosome==?
Autolysis==cellular atombombs
Tonoplast facilitates — transport and helps in —-
active
osmoregulation
cell sap of vacuole has water soluble pigment called
anthocyanin
—- unless specifically stained, are not easily visible under the microscope.
Mitochondria
The number of mitochondria per cell
is variable depending on the —- activity of the cells. In terms of shape and size also, considerable degree of variability is observed.
physiological
Typically mitochondria is —-shaped or cylindrical having a diameter of — (average 0.5µm) and length —-.
sausage, 0.2-1.0µm
1.0-4.1µm
Each mitochondrion is a double membrane-bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into two — compartments, i.e., the outer compartment and the inner compartment.
aqueous
The inner compartment of mito is called the —-. The outer membrane forms the continuous limiting boundary of the organelle.
matrix
The inner membrane of mito forms a number of infoldings called the — towards the matrix
cristae
The cristae increase the —
surface area
The two membranes
have their own —-associated with the mitochondrial function.
specific enzymes
Mitochondria are the sites of — .
aerobic resp
mito produce cellular energy in the form of —, hence they are called ‘power houses’ of the cell.
ATP
The matrix also possesses — DNA molecule, a few
RNA molecules, ribosomes (–) and the components required for the synthesis of —.
single circular, 70S
proteins
The mitochondria divide by —.
fission
___ are called endosymbionts of the cell
Mito
mito was discovered by
kollekar
Prokaryotic cell within eu is
mito and chloro
1 cell can have — mito
60k
group==chondrisome
—- has only 1 mito
chlorella fusca
stain used to see mito is
janus green
— membrane of mito is selectively permeable because of
inner, cardiolipids
fernandez particles are present on
inner lining of mito
also called: atp synthetase, oxysomes or elementary particles
oxidative phosphorylation takes place in
F1 in matrix of fernandes particle of mito
inner membrane of mito has electron carrying —- which forms the electron transport system
cytochromes
Plastids are found in all plant cells and in —. These are easily
observed under the microscope as they are —.
euglenoides, large
Plastids bear some specific —, thus imparting specific colours to the plants. Based on the
type of pigments plastids can be classified into —,— and —-
pigments
chloroplasts, chromoplasts and leucoplasts.
The chloroplasts contain chlorophyll and — pigments which
are responsible for trapping light energy essential for —.
carotenoid, photosynthesis
In the chromoplasts — carotenoid pigments like carotene, xanthophylls and others are present. This gives the part of the plant a — — or —- colour.
fat soluble
yellow, orange or red
The leucoplasts are the colourless plastids
of varied— and — with stored nutrients:
shapes and sizes
Amyloplasts store
—- (starch), e.g., potato; —store oils and fats whereas the aleuroplasts store —.
carbohydrates
elaioplasts
proteins
Majority of the chloroplasts of the
green plants are found in the — cells of the leaves.
mesophyll
Chloroplasts are —shaped, oval, spherical, —or even ribbon-like
organelles having variable length (—) and width (–).
lens, discoid
5-10µm, 2-4µm
The number of chlroplast varies from 1 per cell of the —, a green alga to – per cell in the mesophyll.
Chlamydomonas
20-40
The inner —- membrane is relatively less permeable than the inner membrane of —-.
chloroplast , mito
The space limited by the inner membrane of the chloroplast is called the —.
stroma
A number of organised —- called the thylakoids,
are present in the stroma
flattened membranous sacs
Thylakoids are arranged in stacks like the piles of coins called — or the —.
grana, intergranal
thylakoids
In addition, there are flat membranous tubules called the s— connecting the thylakoids of the different grana. The
membrane of the thylakoids enclose a space called a lumen.
stroma lamellae
The stroma of the chloroplast contains enzymes required for the synthesis of — and —.
carbohydrates and proteins
Chlorophyll pigments are
present in the —-. The ribosomes of the chloroplasts are smaller
(—-) than the cytoplasmic ribosomes (80S).
thylakoids
70S
chlro also contains small, — circular DNA molecules and ribosomes.
double-stranded
Dark rean and light rean occurs in the — of chloro
stroma, granum
—- is the worlds most abundant enzyme found in the stroma of chloro
rubisco- ribulose bisphosphate carboxylase oxygenase
(Participates in carboxylation and oxygenation)
functional unit of chloro
quantasome-
chl a,b, caratenoids and xanthophylls
(present in interthylakoidal space)
dense structures called ribosomes were discovered by
george palade- 1953
hence called palade granules
ribosomes are
composed of ribonucleic acid (RNA) and — and are not surrounded
by any membrane.
proteins
‘S’ (—-) stands for the sedimentation coefficient;
it indirectly is a measure of — and —.
Svedberg’s Unit
density and size
Both 70S and 80S ribosomes are composed of — subunits
2
—- is a organelle within a organelle
ribosomes
workbenches of proteins===
ribosomes
for 2 subunits of ribosome to join and form diamer, —- is req
0.001 molar Mg +2 is req
Cilia and flagella are —like outgrowths of the cell membrane. Cilia are small structures which work like –, causing the movement of either the cell or the —. Flagella are comparatively longer and responsible for —movement.
hair
oars, surrounding fluid
cell
The cytoskeleton in a cell are involved in many functions such as — support, —, maintenance of the shape of the cell.
mechanical, motility
An elaborate network of filamentous —- structures present in the cytoplasm is collectively referred to as the cytoskeleton.
proteinaceous
The prokaryotic bacteria also possess flagella but these are structurally
— from that of the eukaryotic flagella.
different
The electron microscopic study of a cilium or the flagellum show that
they are covered with plasma membrane. Their core called the —–,
possesses a number of —- running parallel to the long axis.
axoneme, microtubules
The axoneme usually has — pairs of doublets of radially arranged
peripheral microtubules, and a — of centrally located microtubules.
Such an arrangement of axonemal microtubules is referred to as the —
array
nine, pair
9+2
The central tubules are connected by — and is also enclosed by a central sheath, which is connected to one of the tubules of each peripheral doublets by a —-. Thus, there are nine radial
spokes. The peripheral doublets are also interconnected by linkers.
bridges, radial spoke
Both the cilium and flagellum emerge from —-like structure called the
—–.
centriole, basal bodies
Centrosome is an organelle usually containing two cylindrical structures called —-. They are surrounded by amorphous —- materials.
centrioles
pericentriolar
Both the centrioles in a centrosome lie — to each
other in which each has an organisation like the —.
perpendicular, cartwheel
The centriole is made up of nine evenly spaced peripheral fibrils of — protein. Each of the peripheral fibril is a —.The adjacent triplets are also linked.
tubulin, triplet
The central part of the proximal region of the centriole is also —
and called the —, which is connected with tubules of the peripheral triplets by radial spokes made of protein.
proteinaceous, hub
The centrioles form the basal body of cilia or flagella, and —that give rise to spindle apparatus during cell division in animal cells.
spindle fibres
Nucleus as a cell organelle was first described by Robert Brown as early as —. Later the material of the nucleus stained by the — dyes was given the name chromatin by —-.
1831
basic, Flemming
The — nucleus (nucleus of a cell when it is not dividing) has highly
extended and elaborate —called chromatin, nuclear matrix and one or more spherical bodies called —
interphase
nucleoprotein fibres
nucleoli
Electron microscopy has revealed that the nuclear envelope, which consists of two —- membranes with a space between (—) called the perinuclear space, forms a — between the materials
present inside the nucleus and that of the
cytoplasm.
parallel, 10 to 50 nm
barrier
The outer membrane of nucleus usually remains continuous with the —- and also bears —- on it.
endoplasmic reticulum
ribosomes
At a number of places the nuclear envelope is interrupted by minute
pores called—-, which are formed by the — of its two membranes.
Anulus, fusion
These nuclear pores are the passages through which movement of — and — molecules takes place in both directions between the nucleus and the cytoplasm.
RNA and protein
Normally, there is only —nucleus per cell, variations in the number of nuclei are also frequently observed.
one
Some mature
cells even lack nucleus, e.g., —- of many mammals and — of vascular plants.
erythrocytes , sieve
tube cells
The nuclear matrix or the nucleoplasm contains — and —.
nucleolus and chromatin
The nucleoli are spherical structures present in the
nucleoplasm. The content of nucleolus is — with the rest of the nucleoplasm as it is —structure.
continuous, not a membrane bound
Nucleolus is a site for active—- synthesis.
ribosomal RNA
Larger and more numerous nucleoli are
present in cells actively carrying out — synthesis.
protein
But during different stages of cell division, cells show structured — in place of the nucleus.
chromosomes
Chromatin contains DNA and some basic proteins called —, some non-histone proteins and also RNA.
histones
A single human cell has approximately — long
thread of DNA distributed among its forty six (twenty three pairs) chromosomes.
two metre
Every chromosome essentially has a —- or the centromere on the sides of which disc shaped structures called — are present
primary constriction
kinetochores
Based on the position of the —-, the chromosomes can be classified into four types
centromere
The — chromosome has middle centromere forming two equal arms of the chromosome.
metacentric
The sub-metacentric chromosome has centromere —- of the chromosome resulting
into one shorter arm and one longer arm.
slightly away from the middle, L shape
In case of —chromosome the centromere is situated close to its end forming one extremely short and one very long
arm, whereas the telocentric chromosome has a —-
acrocentric ( J shape), terminal centromere
(I shape)
Sometimes a few chromosomes have — secondary constrictions at a constant location. This gives the appearance of a small fragment called the —.
non-staining, satellite
Many membrane bound — called microbodies that contain various enzymes, are present in both plant and animal cells.
minute vesicles
Peroxisomes also called —- have enzyme —- which help in?
uricosomes,
catalase or peroxidase
conversion of h2o2 to h2o + o
Glyoxysomes are present in — cells and participate i —- cycle
plants, glyoxilate cycle (hydrolases fats, converts fats to carbs)
Spherosomes act as —- and help in storage of —
lysosomes, lipids
coenocytic condition is seen in — cells
rhizopus and muscle cell
nuclear membrane is also called
karyotheca/karyolemma
Darkly strained, lightly packed, transcriptionally inactive chromatin is
heterochromatin
proteinaceous layer around chromosome==
pellicle
Telomere- end of chromosomes have more —-
guanine
isobrachial chromose shape is
metacentric, v shape
Clearly visible chromosomes that are useful for karyotypic studies are found in — stage of cell cycle
Metaphase
Nucleolus + Secondary constriction is called
Nucleolar organization region
In humans —- chromosomes have secondary constrictions and therefore a nucleolus?
13, 14, 15, 21 and 22
Ribosomal factory is
Nucleolus
At maturity tracheids have cell wall but no —
PM
