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
