Chapter 1 - Cell Flashcards
_______ was an outstanding figure in the field of protein structure and as also the founder of madras school .
Als discovered triple helical structure of collagen ..
G.N.Ramachandran
At Cambridge , G.N.Ramachandan met _______ .
Linus Pauling
Who first saw and described a LIVE cell ?
Anton Von Leeuwenhoek
______ discovered nucleus .
Robert brown
_____ in the year ______ observed -all plants are composed of different kinds of cells which form the tissues of the plant .
Matthias Schleiden - a GERMAN BOTANIST
Year 1838
_____ in the year ______ studied different types of animal cells and reported that cells have a PLASMA MEMBRANE .
Theodore Schwann-British zoologist
1839
Presence of cell wall is a unique character of plant cells - was given by ?
Theodore Schwann
______ proposed the hypothesis that the bodies of animals and plants are composed of cells and products of cells .
Theodore Schwann
Echo formulated the cell theory ?
Schleiden and Schwann
Out of Schleiden and Schwann , who was German and who was British and who was a zoologist and who a botanist ?
Schleiden - German botanist
Schwann - British zoologist
Omnis cellula -e cellula was given by ______ in the year _________ .
Rudolf Virchow
1855
Who modified the hypothesis of Schleiden and Schwann to give the cell theory a final shape ?
Rudolf Virchow -new cells arise from pre-existing cells
2 postulates of cell theory -
1- all living organisms are composed of cells and products of cells
2-all cells arise from pre-existing cells
The _____ is the main arena of cellular activities in both plant and animal cells .
Cytoplasm
Various _____ reactions occur in the cytoplasm to keep the cell in the living state.
Chemical
_____ cells lack membrane bound organelles .
Prokaryotic cells
_____ are NON-MEMBRANE BOUND organelles found in both eukaryotic and prokaryotic cells .
Ribosomes
Animal cells contain _____ which helps in cell division .
Centrosome - non membrane bound
Centrosomes have membranes or not .
Non-membrane bound
Size of mycoplasma =
0.3 um in length (micrometer )
Size of bacteria in micrometer =
3 to 5 um
1-2 um given in the diagram
Diameter of human RBCs -
7 um
Longest cells=
Nerve cells
PPLO and mycoplasma are Pro or eukaryotic ?
Prokaryotic
Size of a typical eukaryotic cell =
10-20 micrometer
Size of viruses .
0.02-0.2 micrometer
Size of PPLO-
0.1 um
All prokaryotes have a ______ surrounding the cell membrane .
Cell wall
Exception-mycoplasma
The naked genetic material of prokaryotic cell is -
Genomic DNA - single chromosome/circular DNA 🧬
Many ______ have a small circular DNA outside the genomic DNA 🧬 called PLASMID .
Bacteria 🧫
The plasmid DNA confers certain unique ______ characters to bacteria 🧫.
Phenotypic
Example- resistance to antibiotics
_____ is used to monitor bacterial transformations with foreign DNA .
Plasmid DNA
Prokaryotes have something unique in the form of -
Inclusions
Mesosome is a differentiated form of -
Plasma membrane
Mesosome is a characteristic of-
Prokaryotes
A specialised differentiated form of cell membrane called ______ is a characteristic of prokaryotes .
Mesosome
Infoldings of cell membrane found in prokaryotes-
Mesosome
Although each layer of the cell envelope performs a distinct function , they act together as a ________ unit .
Single PROTECTIVE unit
On what basis can bacteria be divided into 2 groups ?
1 -difference in the cell envelope
2 - how they respond to staining procedure
Those bacteria which take up gram stain are called _______ and those which do not are called ________ .
Gram positive
Gram negative
GLYCOCALYX differs in ______ and _________ among different bacteria 🧫.
Composition
Thickness
Glycocalyx may be a loose sheath called ______ in some , while in others it may be thick and tough called _______ .
Slime layer
Capsule
______ determines the shape of the cell and prevents it from bursting or collapsing .
Cell wall
Plasma membrane is ______ permeable .
Selectively -interacts with the outside world 🌍
______ is similar structurally to that of the eukaryotes .
Cell wall/membrane
Cell membrane
________ interacts with the outside world and is selectively permeable .
Cell membrane
Membranous structure called mesosome is formed by the extension of plasma membrane into the ______ .
Cell
The extensions called mesosomes are in the form of ___ ,_____ and ______.
Vesicles
Tubules
Lamellae
Functions of mesosomes -
Cell wall formation
DNA replication and distribution to daughter cells
Respiration and secretion , to increase the surface area of the plasma membrane and enzymatic content .
Mesosomes help in _______and ________ processes to increase the surface area of the plasma membrane and enzymatic content .
Respiration
Secretion
Bacterial cells are motile/non-motile.
May be motile or non-motile
Bacteria show a range in the _____ and ______ of flagella .
Number
Arrangement
Bacterial flagella is composed of how many parts ?
3
Filament
Hook
Basal body
In the bacterial flagella , _____ is the longest portion and extends from the cell surface to the outside .
Filament
_____ and _____ are surface structures but do not play a role in motility . They attach the bacteria to rocks in streams and to the host tissues
Pili
Fimbrae
___ are elongated tubular structures made of special proteins .
______ are small bristle-like fibres sprouting out of the cell .
Pili
Fimbriae
Apart from mesosomes , other membranous extensions into the cytoplasm seen in CYANOBACTERIA are called -
Chromatophores-pigmented
Chromatophores and mesosomes are ______ extensions in PROKARYOTES .
Membranous
In prokaryotes , ribosomes are associated with the _______ of the cell .
Plasma membrane
Ribosomes in prokaryotes are __________ in size .
15nm by 20nm
Ribosomes in prokaryotes are made of _____ and _____ units which when present together form _____ ribosomes .
50S and 30S
70S
In prokaryotes , several ribosomes may attach to a single mRNA and form a chain called -
Polyribosome / polysome
The ribosomes of a ______ translate the mRNA into proteins .
Polysome
Reserve materials in PROKARYOTIC cells are stored in the cytoplasm in the form of -
Inclusion bodies
Inclusion bodies are not bound by any membrane system and lie freely in the cytoplasm . T/F
T
Examples of inclusion bodies .
Phosphate granules
Cyanophycean granules
Glycogen granules
(Gas vacuoles -maybe )
Gas vacuoles are found in -
Blue green , purple and green photosynthetic bacteria
Or
BGA
Purple and green photosynthetic bacteria
In ______ cells , there is a extensive compartmentalisation of cytoplasm through the presence of membrane bound organelles .
Eukaryotic
The genetic material of eukaryotes is organised into -
Chromosomes
The detailed structure of cell membrane was studied only after the advent of ______ in the ______ .
Electron microscope 🔬
1950s
Chemical studies on the cell membrane in ________ enabled the scientists to deduce the possible structure of cell membrane. .
Human RBC
Studies on human RBC showed that cell membrane is mainly composed of ______ and ______ .
Lipids
Proteins
The major lipid of plasma membrane is arranged in a -
Bilayer
Major lipid-phospholipid
The lipids are arranged within the membrane with the ________ towards the outer side and ______ towards the inner part.
Polar head -outer
Hydrophobic / non-polar tail -inner
The non-polar tail of SATURATED hydrocarbons is protected from __________ ( in the plasma membrane structure ).
Aqueous environment
In addition to phospholipids , the plasma membrane also contains -
Cholesterol
Later , BIOCHEMICAL investigation clearly revealed that the cell membrane also possess _____ and _____ .
Proteins
Carbohydrates
The ratio of _____ and ____ vary in different types of cells membranes in cells .
Proteins
Lipid
In the cell membrane of human RBCs _____ % of proteins and ______ % of lipids are found .
52% proteins
40% lipids
Depending on the ease of EXTRACTION , membrane proteins can be classified as ______ and ______ .
Integral
Peripheral
_____ proteins are partially or wholly buried in the cell membrane .
Integral
While peripheral proteins lie on the surface
An improved model of the structure of cell membrane was proposed by _____ and ______ in the year _______ .
Singer and nicolson
1972
According to fluid mosaic model , ________ nature of lipid enables lateral movement of proteins within the overall bilayer .
Quasi-fluid
The ability of lipid and proteins to move within the membrane is measured as its _______.
Fluidity
The FLUID nature of the membrane is important from the point of view of functions like-
Cell growth Formation of intercellular junctions Secretion Endocytosis Cell division
One of the MST important functions of plasma membrane is -
Transport of molecules across it
neutral molecules move across the plasma membrane by the process________ .
Simple diffusion -along the conc gradient ( from high conc to low )
The ______ molecules cannot pass through the _______ lipid bilayer .
(Polar/non-polar)
Polar
Non-polar
How are polar molecules transported across the plasma membrane through which process?
They require a carrier protein of the membrane to facilitate their transport across the membrane . Facilitated transport .
Some ions are transported across the membrane against their conc gradient . This process is energy dependent and utilises ATP and is called -
Active transport
Na / K pump
Active transport across plasma membrane is an ______ dependent process .
Energy
Cell wall is living or not ?
Non-living
Cell wall forms the outer covering for the ______ in plants and animals .
Cell membrane
______ helps in cell-to-cell interaction and provides barrier to undesirable MACROMOLECULES .
Cell wall
Algae have a cell wall made of -
Cellulose
Gala tans
Mannans
Calcium carbonate
Generally , in plants , cell wall is made up of -
Cellulose
Hemicellulose
Pectins
Proteins
The cell of a young plant , the ________ wall is capable of GROWTH which gradually diminishes as the cell matures and the _____ wall is formed .
Primary
Secondary
Secondary wall of the CELL WALL is formed on the ______ side of the cell .
Inner side-towards membrane
Function of middle lamella -
Holds or glues the different neighbouring cells together
The middle lamella is a layer of _____ .
Calcium pectate
The ______ and _______ may be traversed by plasmodesmata which connect the cytoplasm of neighbouring cells .
Cell wall
Middle lamella
Many MEMBRANOUS organelles are considered together as an endomembrane system because -
Their functions are coordinated
Organelles which are a part of an endomembrane system -
4 ER Golgi apparatus Lysosomes Vacuoles
_____ divides the intracellular space into 2 parts compartments ( luminal and extra luminal )
ER
ER divides the INTRACELLULAR space into which distinct compartments .
Luminal - inside ER
Extra luminal -cytoplasm
The ER often shows ribosomes attached to the _____ surface .
Outer
In the absence of ______ ,ER appears smooth .
Ribosomes
RER is frequently observed in cells actively involved in ________ and _______ .
Protein synthesis
Secretion
______ are EXTENSIVE and continuous with the outer membrane of the nucleus .
RER
