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
Simple diffusion occurs along the _____ gradient
concentration
Movement of water by diffusion is called
osmosis
The type of molecules which require protein to facilitate their transport across membrane are
polar molecules
The proteins required by polar molecules to facilitate their treansport are called
carrier proteins
During active transport, molecules are transported _____ the concentation gradient
against
Active transport occurs with the utilization of ______
ATP
The type of transport during which ATP is utilised is
Active transport
An example of active transport is
Na+/ K+ pump
The non living rigid structure forming the outer covering of plasma membrane in fungi and plants is called
cell wall
Cell wall acts as an outer covering for which membrane?
plasma membrane
_____ forms an outer covering for the plasma membrane of fungi and plants
cell wall
Cell wall protects the cell from _____ and _____
mechanical damage and infection
Cell wall provides barrier to _____
undesirable macromolecules
Algae cell wall is primarily composed of
cellulose, galactans, mannans and mineral like calcium carbonate
Name a mineral component of algal cell wall
calcium carbonate
Plant cell wall is composed of
cellulose, hemicellulose, pectins and proteins
The cell wall of young plants which is capable of growth is
primary wall
The layer of cell which specifically holds different neighbouring cells together in plants is
middle lamella
Middle lamella in plants mainly composed of
calcium pectate
The cell wall and middle lamellae are traversed by _____
plasmodesmata
Cytoplasm of neighbouring cells are connected by _____
plasmodesmata
ER, golgi complex, lysosomes and vacuoles are the part of _____ system
endomembrane system
The organelles whose functions are coordinated, are considered as a part of ____ system
endomembrane
Name three organelles which are not a part of endomembrane system
mitochondria, chloroplast and peroxisomes
The organelle which divides intracellular space into luminal and extra luminal is
endoplasmic recticulum
The recticulum of tiny tubular structures scattered in the cytoplasm is called
endoplasmic recticulum
The region inside ER is called
luminal
The region outside ER is called
extra luminal
The ER often shows _____ attached to their outer surface
ribosomes
The endoplasmic reticulum bearing ribosomes on their surface is called
RER
The ER devoid of ribosomes is called as
SER
The ER involved in active protein synthesis is
RER
RER is _____ and continous with the outer membrane of the _____
extensive; nucleus
The site of lipid syntheisis in ER is
SER
Lipids like steroidal hormones in animals cells are synthesised by
SER
Golgi bodies were first observed by
camillo golgi
Flat, disc-shaped sacs are called
cisternae
The diameter of sacs of Golgi varies from_____ to _____
0.5 um to 1 um
The golgi cisternae around nucleus are arranged _____
concentrically
The forming face of golgi body is called
convex cis
Concave trans is the _____ face of golgi body
maturing
The primary function of golgi apparatus is
packaging of materials
Materials to be packed in the form of vesicles from ER fuse with which face of golgi?
cis
Proteins synthesised by ribosomes are modified by
golgi apparatus
Modified roteins from cisternae are released through ____ of golgi apparatus
trans face
Golgi apparatus is an important site for the formation of _____ and ______
glycoproteins and glycolipids
Membrane bound vesicular structures formed by the process of packing in the golgi apprartus are called
lysosomes
Which organelle forms lysosomes?
golgi apparatus
Lysosomal vesicles are rich in ______
hydrolytic enzymes
The hydrolases present in lysosomes are -
lipases, proteases, carbohydrases
Enzymes of lysosomal vesicles get active at ____ pH
acidic
Carbohydrates, proteins, lipids and nuclei acids in lysosomes are digested by enzymes
Hydrolases
The membrane bound space found in cytoplasm is
vacuole
Water, sap, excretory waste are stored in
vacuoles
The vacuole is bound by a single membrane called
tonoplast
Vacuoles can occupy upto how much volume of plant cell?
90%
The transport of number of ions and other materials against concentration gradients into the vacuole is facilitated by
tonoplast
The vacuole responsible for excretion in Amoeba is
contractile vacuole
Food vacuoles are formed by engulfing food particles in
protists
The number of mitochondria in a cell depends on _____ of the cell
physiological activity
The diameter of mitochondria varies from ____ to _____
0.2 to 1 um
The length of mitochondria varies from ____ to ____
1 to 4.1 um
Each mitochondrion is a ____ structure
double membrane-bound
The inner compartment of mitochondria is filled witha dense homogenous sustance called
matrix
The membrane of mitochondria forming the continous limitiong boundary of the organelle is
outer mitochondrial membrane
The inner mitochondrial membrane forms a number of infoldinds called
cristae
The infoldings increasing the surface area of mitochondria are
cristae
Mitochondria is the site of which respiration?
Aerobic respiration
Energy is released by mitochondria in the form of
ATP
Mitochondria is also called
power house of cell
The ribosomal subunits preesnt in mitochondrial matrix are
70S
Mitochondria divides by
fission
The pigment imparting organelles present in plants and some euglenoids is
plastids
Plastids are classified into chloroplast, leucoplast and chromoplast on the basis of
Pigments
Choroplhyll containing plastids are called
chloroplasts
Along with chlorophyll, chloroplast contains
carotenoids pigments
Light energy trapped by pigments of chloroplats is required for
photosynthesis
Name two fat soluble carotenoids pigments of chromoplasts
carotene and xanthophyll
The three colours provided to plants by chromoplast are
yellow, orange or red colour
The colourless plastids are called
leucoplats
The function of leucoplast is to
store nutrients
Carbohydrates storing leucoplasts are called
amyloplasts
Leucoplast storing oils and fats is called
Elaioplasts
Protein storing leucoplast is known as
Aleuroplasts
Majority of chloroplast of green plants is found in which cells?
Mesophyll cells
Number of chloroplast in Chlamydomonas is ___ per cell
one
Number of chloroplast in a mesophyll cell is _____ per cell
20-40
______ chloroplast membrane is less permeabe
Inner
The space limited by inner membrane of the chloroplast is called
Stroma
Thylakoids are present in
stroma
A number of organised flattened membranous sacs present in the stroma are called
Thylakoids
Thylakoids are arranged in piles called
grana
The flat membranous tubule joining thylakoids of different grana are called
stroma lamella
The stroma of chloroplast contains enzymes required for the synthesis of ____ and ____
carbohydrates and proteins
The pigments present in thylakoids are called
chlorophyll pigments
The ribosomal subunit present in chloroplast is
70S
Ribosomes were first observed under electron microscope by
george palade
Ribosomes are composed of _____ and _____
RNA and proteins
The membrane less, protein syn thesising organelles are called
ribosomes
The eukaryotic ribosome is ____
80S
The prokaryotic ribosome is ____
70S
The two subunits of 80S ribosome are
60S and 40S
The two subunits of 70S ribosome are
50S and 30S
S (Svedberg’s Unit) in ribosomal subunit stands for
Sedimentation coefficient
Sedimentation coefficient is the measure of _____ and _____
density and size
An elaborate network of filamentous proteinaceous structures consisting of microtubules, microfilaments and intermediate filaments present in the cytoplasm is collectively referred to as
cytoskeleton
Cytoskeleton is composed of proteinaceous structures like
microtubules, microfilaments and intermediate filaments
Two hair like outgrowths of the cell membrane are
cilia and flagella
The small structures causing movement of either cell surrounding fluid are called
Cilium
The small structures causing movement of either cell surrounding fluid are called
Cilium
An extension longer than cilia which is responsible for cellular movement is
Flagella
Cilium and flagellum are covered by
Plasma membrane
The core of flagellum or cilium is called
axoneme
Axoneme consists of number of _____ running in parallel to long axis
microtubules
Axoneme has ____ of radially arranged peripheral microtubules
nine doublets
The arrangement of axonemal microtubules is called
9+2 array
Central sheath is connected to one of the tubules of each peripheral doublets by
radial spoke
The number of radial spokes in 9 + 2 arrangement is
Nine
Peripheral doublets are interconnected by
Linkers
The cilium and flagellum emerge from centriole like structure called
basal bodies
An organelle usually containing two cylindrical structures called
centrosome
Centrosomes are surrounded by
amorphous pericentriolar material
Centrioles in centrosome lie _____ to each other
perpendicular
Centrioles are made up of ____ evenly spaced peripheral fibrils of tubulin protein
nine
The protein forming peripheral fibrils in centriole is
Tubulin protein
Each of the _____ in centriole is a triplet
peripheral fibril
The proteinaceous, cental part of proximal region of centriole is called
hub
Hub is connected with tubules of peripheral triplets by
radial spokes
Radial spokes are composed of
Protein
The basal body of cilia or flagella is formed by
Centrioles
The basal body of spindle fibres is formed by
Centriole
Nucleus was first described by
Robert brown
The material of the nucleus stained by the basic dyes was given by the name chromatin by
Flemming
Nucleolus, chromatin and nuclear matrix are characteristics of which nucleus ?
Interphase nucleus
The space between two parallel membrane of nuclear envelope is called
perinuclear envelope
The outer membrane of nucleus remains continous with
endoplasmic reticulum
The outer membrane of nucleus remains continuous with ER and bears
ribosomes
Movement of RNA and protein between nucleus and cytoplasm takes place through
nuclear pores
Some mature cells in mammals lacking nucleus are
Erthrocytes
The plant cells devoid of nucleus are
Sieve tube cells
The nuclear matrix or the nucleoplasm contains _____ and _____
nucleus and chromatin
The spherical structures present in nucleoplasm are called
nucleoli
The site of active ribosomal RNA synthesis in nucleus is
Nucleolus
Chromatin primarily contains
DNA
Basic proteins present in chromatin are
histones
Human beings have _____ pairs of chromosomes
23
The primary constriction on chromosome is called
Centromere
Kinetochores are present on the sides of
Centromere
The disc shaped structures present on the sides of centromere are called
KInetochores
A chromosomes having middle centromere forming two equal arms of the chromosome is called
Metacentric chromosome
A chromosome whose centromere is slightly away from the middle of the chromosome resulting in one shorter and one longer arm is called
sub-metacentric chromosome
The centromere is situated close to its end forming one extremely short and one very long arm in ____ chromosome
acrocentric chromosome
Chromosomes having terminal centromere are called
Telocentric chromosome
Secondary constriction in chromosomes give appearance of __________
satellite
Minute enzyme containing vesicles in both plants and animals are called
Microbodies
Each mitochondrion is a double membrane-bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into _____ compartments.
Two aqueous compartments
