Cell - The unit of life Flashcards
The structural and fundamental unit of life is
cell
Living cell was first described by
Anton Von Leeuwenhoek
The nucleus was discovered by
Robert brown
The structural components of a cell were well defined after the discovery of _____
electron microscope
A german botanist who observed that all plants are composed of different kinds of cells which form tissues was
Matthias Schleiden
The thin outer layer of animal cells, now known as plasma membrane, was first reported by
Theodore Schwann
The scientists who together formulated the cell theory were ____ and _____
Schleiden and Schwann
The scientist who first explained that cells divide and new cells form from pre-existing cells was
Rudolf Virchow
The outer boundary of a typical plant cell is _____
cell wall
DNA containing chromosomes are structures located inside _____
nucleus
The cells which possess membrane bound nuclei are called
Eukaryotic
Cells which lack membrane bound nucleus are called
prokaryotic
The cell volume is occupied by semi-fluid matrix is called as
cytoplasm
Majority of cellular activities which keep a cell in living state are performed in ____
cytoplasm
The non-membrane bound organelles found in both prokaryotic and eukaryotic cell is
ribosomes
The organelle which contains ribosomes and is specifically present in plants is
chloroplast
Apart from cytoplasm, organelles containing ribosomes in animals are
Mitochondria and rough ER
The type of ER possessing ribosomes is
rough ER
A non membrane bound organelle which helps in cell division is
centrosome
The smallest living cells are
Mycoplasma
The length of mycoplasmas is
0.3um
The size of bacteria ranges from
3 to 5im
The largest isolated single cell is an egg of _____
ostrich
Diameter of a human RBC is
7um
Name four prokaryotes
bacteria, blue - green algae, mycoplasma and PPLO
PPLO stands for
Pleuro Pneumonia Like organisms
The rod shaped bacteria are generally called
Bacillus
The spherical shaped bacteria are generally called
Coccus
The comma shaped bacteria are generally called
Vibrio
The shape of spirillium bacteria
Spiral
A prokaryote which lack cell wall is
Mycoplasma
The fluid matrix filling a cell is
cytoplasm
Naked nucleus without nuclear membrane are characteristics of
Prokaryotes
A small circular DNA outside genomic DNA in bacteria is
Plasmid DNA
A phenotypic character provided to bacteria by plasmid DNA is
Resistance to antibiotics
The ______ conifers certain unique phenotypic characters to bacteria
Plasmid DNA
Well organised nucleus with a nuclear membrane is the characteristic feature of _____ cells
Eukaryotic
_____ is the only organelle found in both prokaryotes and eukaryotes
ribosomes
A specialised differentiated form of cell membrane called ____ is the characteristic of prokaryotes
mesosomes
Mesosomes are essential infoldings of
cell membrane
Tightly bound three layered structure of bacterial cell envelope consists of
Glycocalyx, cell wall and plasma membrane
The three layered cell envelope of bacteria is ____ in function
protective
The outermost layer of cell envelope in bacteria is
glycocalyx
On the basis of gram staining, bacteria are classified as
Gram positive and gram negative
Bacteria that take up the gram stain are ____ and the others that donot are called _____ bacteria
gram positive; gram negative
The layer of cell envelope whose composition and thickness varies to large extent
Glycocalyx
The loose sheath of glycocalyx in bacteria is called
Slime layer
The thick sheath of glycocalyx in bacteria is called
capsule
Which determines the shape of cell?
cell wall
The structural component of a abcterial cell that prevents bacterium from byrsting or collapsing
cell wall
The selectively permeable membrane of cells is
plasma membrane
The membrane which is structurally similar in prokaryotes and eukaryotes is
plasma membrane
A membranous structure which is formed by the extensions of plasma membrane into the cells is
mesosome
The extensions of cell membrane are in the form of
vesicles, tubules and lamella
One major role of mesosomes is
DNA replication/ cell wall formation/DNA distribution
Which part of cell membrane assists in DNA replication?
Mesosomes
The surface area of plasma membrane gets increased due to the presence of
Mesosome
Pigment containing membranous extensions in cyanobacteria are called
chromatophores
Motile bacteria have thin filamentous extensions from their cell wall, known as
flagella
The three main parts of bacterial flagellum are
filament, hook and basal body
The longest portion of bacterial flagellum is
filament
The two surface structures of bacteria which donot play role in locomotion are
pili and fimbrae
The elongated tubular structures composed of protein in bacteria are
pili
Small bristle like fibres sprouting out of the bacterial cell are
fimbrae
The structures which are known to attach bacteria to rocks in streams or to hosts are
fimbrae
Ribosomes are associated with the _____ of cell in prokaryotes
plasma membrane
The average size of prokaryotic ribosome is
15 nm by 20 nm
The two sub-units of prokaryotic ribosomes are
50S and 30S
50S and 30S subunits of prokaryotic ribosomes together form
70S
Ribosomes are the site of
Protein synthesis
Several ribosomes may attach to a single mRNA and form a chain called ____
Polyribosomes or polysome
The ribosomes of a polysome translate the ____ into _____
mRNA into proteins
Reserve material in prokaryotic cells is stored in the cytoplasm in the form of
Inclusion bodies
Phosphate granule is an example of
Inclusion body
Gas vacuoles are the types of _____ bodies found in blue green and purple and green photosynthetic bacteria
inclusion
Gas vacuoles are found in which bacteria?
blue green, purple and green photosynthetic bacteria
In eukaryotic cells, there is an extensive compartmentalisation of cytoplasm through the presence of _____
membrane bound organelles
The cells possessing complex locomotory and cytoskeletal structures are
Eukaryotic cells
Eukaryotic cells possess and organised nucleus with
nuclear envelope
The genetic material of eukaryoties is organised into
chromosomes
The organelles that are present in plant cell but not in animal cell are
plastids
The characteristic feature of animal cells in the presence of
Centrioles
The chemical studies on the cell membrane, especially in _____,enabled the scientist to deduce the possible structure of plasma membrane
Human red blood cells (RBC)
Cell membrane is mainly composed of
Lipids and proteins
The major lipids in cell membrane are
phospholipids
Phospholipids in cell membrane are arranged in a
bilayer
In a lipid bilayer, the part of lipids that lie towards inside is
hydrophobic tails
In addition to phospholipids membrane also contains _____
cholesterol
Apart from cholesterol and lipids, other biomolecules that make up the cell membrane are
proteins and carbohydrates
The % of proteins in membrane of human erythrocyte is
52%
The % of lipid in membrane of human erythrocyte is
40%
Membrane proteins are classified as
integral and peripheral proteins
The proteins that lie on the surface of membrane are called
peripheral proteins
The protens that are partially or totally buried in membrane are called
integral proteins
The fluid mosaic model was proposed by
singer and nicolson
Fluid mosaic model was proposed in year
1972
According to fluid mosaic model, what nature of lipid enables lateral movement of proteins?
Quasi-fluid nature
The quasi-fluid nature of lipid enables which movement of proteins within bilayer?
lateral movement
The ability of protein to move within membrane is measured as its _____
fluidity
The fluid nature of membrane is important for
cellular functions
Transport of molecules across itself is the most important function of _____
plasma membrane
The nature of permeability of plasma membrane is
selectively membrane
The movement of molecules across the membrane without any requirement of energy is called
passive transport
Neutral molecules move across the membrane by the process of
simple diffusion
