XI: Chapter 8- Cell the unit of life Flashcards
Who is the father of cytology?
Robert Hooke
Who is the father of microscopy?
A.V. Leeuwenhook
Who coined the term cell?
Robert Hooke
Who discovered the first living cell?
A.V. Leeuwenhook
Which botanist contributed to the cell theory?
M. Schledein
Which zoologist contributed to the cell theory?
T. Schwann
Who proposed the cell lineage theory?
Rudolf Virchow
Who discovered the nucleus?
Robert Brown
Which is the largest plant cell?
Acetabularia
Which is the largest animal cell?
Ostrich egg cell
Sterols are present in which prokaryote?
Mycoplasma
What is the difference between the structure of pili and fimbriae?
Pili- hollow filament
Fimbrae- solid filament
What is the glycocalyx made of?
Oligosaccharides
What is the difference between the golgi bodies of animals and plants?
A single large golgisome is present in animal cells near the nucleus while dictyosomes are minute, many and scattered.
Which cells have more mitochondria- animal cells or plant cells?
Animal cells
Are centrosomes present in plants?
No
What is deutoplasm?
Non living inclusion bodies in a eukaryotic cell
What is hyaloplasm?
Cytoplasm-organelles-deutoplasm
In which plant cells are cell walls absent?
In gametes of plants
What is the constitution of plant cell wall?
Plant cell wall is made of cellulose macrofibrils embedded in matrix of hemicellulose, pectin and lignin.
What is the constitution of algal cell wall?
Cellulose macrofibrils embedded in matrix of hemicellulose, pectin, galactans and mannans
What is the constitution of fungal cell wall?
Chitin and cellulose macrofibrils embedded in matrix of hemicellulose and pectin
What is the precursor of middle lamella, and what is the middle lamella a precursor of?
Cell plate is the prescursor of middle lamella while middle lamella is the precursor of cell wall.
What makes fruits soft on ripening?
Dissolution of middle lamella (pectinase enzyme)
At which angle are the cellulose microfibrils situated to each other in the cell wall?
120`
What makes the primary cell wall more flexible than the secondary cell wall?
Primary cell wall- more of pectin
Secondary cell wall- more of lignin
Which cell wall is deposited uniformly?
Primary cell wall
What is the tertiary cell wall made of?
Xylans
What are desmotubules of plasmodesmata made of?
Endoplasmic reticulum
What is the tonoplast in a plant cell?
The living semi-permeable single membrane of a vacuole
Does the transport of material across the tonoplast occur against or along the concentration gradient?
Against
Where are anthocyanins stored in a plant cell?
Vacuole
Who discovered the plasma membrane?
Schwann
What is the composition of cell membrane?
40% lipids
52% proteins
8% carbohydrates
Who proposed the sandwhich theory of plasma membrane?
Danielli and Davson
What is the width of the plasma membrane according to the sandwhich theory?
20 Å Protein layer
35 Å lipid bilayer
20 Å Protein layer
Which is the most common phospholipid found in cells?
Lecithin
Who proposed the fluid mosaic model?
Singer and Nicolson
What is the difference in the amount of cholesterol find in plant and animal cell membranes?
Plant cell membranes have less cholesterol or sometimes no cholesterol as compared to animal cell membranes.
What is the function of cholesterol in plasma membrane?
Cholesterol provides stability to the cell membrane.
Lateral movements happen between which layers of cell membrane?
Same layers
What regulates the permeability of cell membrane?
Calcium ions
Sodium potassium pump is the example of which type of active transport?
Direct active transport
SGLT (intestinal mucosa sodium glucose transport) is the example of which type of active transport?
Indirect active transport
GLUT is an example of which type of transport?
Facilated transport
What type of membrane binds the endoplasmic reticulum?
Single membrane
Who discovered the endoplasmic reticulum?
Porter
In which cells is endoplasmic reticulum poorly developed?
In rapidly dividing cells- sperms, ovum and RBCs
What are the structural forms of ER?
Vesicles, tubules and cisternae
How is the larger unit of ribosome attached to RER?
With glycoproteins= ribophorin I and II
Which cell organelle is responsible for detoxification of toxins in liver?
SER
Which cell organelle forms enzyme precursors of lysosomes to be made by golgi bodies?
RER
How is SER able to detoxify toxins in liver?
Because of cytochrome 450
In which cell organelle are calcium ions store in muscle cells?
SER (sarcoplasmic reticulum)
Which organelle forms the cell endoskeleton?
Endoplasmic reticulum
What are the cytoplasmic bridges between two adjacent plant cells?
Plasmodesmata
Which organelle helps in reformation of nuclear membrane at the end of cell division?
ER
What is the functional unit of golgi body?
Cisternae
How many golgiosomes are present in animal cells?
4 to 8
In which human cells are golgi bodies absent?
Mature RBCs
Which is the convex face of golgisome?
Cis face/forming face
Which is the concave face of golgisome?
Trans face/maturing face
Which cell organelle synthesises carbohydrates?
Golgi body
Which cell organelle synthesises glycoproteins and glycolipids?
Golgi body
Which enzyme helps in glycosylation of proteins and lipids in golgibodies?
Glycosyl transferase enzyme
Which organelle is responsible for the formation of cell plate?
Golgi body
Which organelle is responsible for the repairing of cell wall?
Golgi body
Which organelle is responsible for the formation of yolk in egg?
Golgi body
Who discovered lysosomes?
Christian-de-duve
What is the pH of lysosomes?
4 to 5
What is the marker enzyme for lysosome?
Acid phosphatase
Lysosomes are absent in which human cell?
RBCs
Lysosomes are found in which plant cell?
Maize root, tobacco endosperm
How are primary lysosomes formed?
Primary lysosomes form from golgi bodies.
WHat do primary lysosomes contain?
Inactive enzymes
How are secondary lysosomes formed?
Primary lysosomes + food vacuole
What do secondary lysosomes contain?
Active enzymes
What are tertiary lysosomes?
Contain undigested waste
What is the function of an autophagosome?
Recycling of old worn out cell organelles
How are lysosomes related to Tay-Sachs and Gaucher’s disease?
These diseases occur because of the accumulation of tertiary lysosomes
What make lysosomes rupture?
Membrane labilizers
Give examples of membrane labilizers.
Vit A, vit B, sex hormones, bile salts etc
Give examples of membrane stabilizers.
Cortisol, cholesterol, heparin
Can a lysosome rupture on its own?
No
What kind of membrane surrounds the microbodies in a cell?
Single membrane
Which microbody is found in plant cells only?
Sphaerosome
What is the function of sphaerosome?
Lipid storage
Which microbody is known as plant lysosome?
Sphaerosome
Where are glyoxisomes found?
Seeds of plants and fungi
What is the function of glyoxisome?
Conversion of oil/fat to sugar/carbohydrate
Which is the main class of enzymes found in peroxisomes of plants?
Glycolate oxidase
Which is the main class of enzymes found in peroxisomes of animals?
Purine/urate oxidase
Can double membrane bound organelles stay alive outside a cell?
Yes
Which organelles are known as cell within a cell?
Double membrane bound organelles
Which is the largest organelle of an animal cell?
Mitochondria
Aquaporins are present on which membrane of mitochondria?
Outer membrane
Where is succinic dehydrogenase enzyme located in a mitochondria?
Inner membrane
Where are the enzymes of Kreb’s cycle present in a mitochondria?
In the matrix
Where does the β oxidation of fatty acids occur in a cell?
Mitochondria
Which is the largest organelle of a plant cell?
Plastids
Which leucoplast stores starch?
Amyloplast
Which leucoplast stores proteins?
Aleuroplast
Which leucoplast stores fats?
Elaioplast
What are known as Palade particles?
Ribosomes
What is known as organelle within organelle?
Ribosomes
Which is the smallest cell organelle?
Ribosome
At what concentration of Mg2+ ions, the dimer of ribosomes is formed?
0.001 M
How many types of proteins are found in prokaryotic ribosomes?
55 types of proteins
Which RNA form the 50s ribosomal unit?
23s rRNA, 5s rRNA
Which RNA forms the 30s ribosomal unit?
16s rRNA
How many types of proteins form the eukaryotic ribosome?
73 types of proteins
Which RNA form the 60s ribosomal unit?
28s rRNA, 5s rRNA, 5.8s rRNA
Which RNA form the 40s ribosomal unit
18s rRNA
Which rRNA are ribozymes?
23s rRNA and 28s rRNA
Which RNA is extranuclear in origin?
5s rRNA
Which cytoskeletal fibres are thin, solid and contractile?
Microfilaments
Which protein forms microfilaments?
Actin proteins
Which cytoskeletal fibre is responsible for pseudopodia formation and cytolpasmic streaming?
Microfilaments
Which cytoskeletal fibre is strong, solid and contractile?
Intermediate protein fibre
Which protein forms the intermediate protein fibre?
Keratin
Which cytoskeletal fibres are present in desmosomes?
Intermediate protein fibres
Which cytoskeletal fibres form the nuclear basket?
Intermediate protein fibres
Which cytoskeletal fibre is hollow, broad and non contractile?
Microtubules
Which protein forms the microtubules?
1 α-tubulin + 1 β-tubulin
How many protofilaments come together to form a singlet microtubule?
13 protofilaments
What is centrosphere?
It is the amorphous cytoplasm surrounding centrioles
Where are centrosomes located?
Near the nuclear membrane
Which organelle forms the basal body?
Centrosome
What microtubular arrangement is present in centrioles?
9+0
Oocytes lack which cell organelle?
Centriole
What do the linker proteins link in a centriole?
Adjacently placed A and C microtubules
What is the core of cilia/flagella of eukaryotes called?
Axoneme
What is the difference between the peripheral microtubules of centriole and flagella?
Centriole- peripheral triplets
Flagella- peripheral doublets
What links the adjacent peripheral microtubule doublets in flagella/cilia?
Nexin protein
What are the radial spokes of cilia/flagella made of?
Nexin protein
What is the central sheath of axoneme made of in cilia/flagella?
Dyenin protein
What are the inner and outer arms of peripheral microtubules made of in cilia/flagella?
Dyenin protein
What acts as ATPase enzyme in cilia/flagella?
Dyenin protein
What is the pH of nucleoplasm?
7.2 to 7.5
What makes the nucleoplasm basic in nature?
Presence of large amounts of nucleosides
How many histone proteins are present in a nucleosome?
5 types of histone proteins
Which histone protein is called the linker protein?
H1
Which is more condensed- euchromatin or heterochromatin?
Heterochromatin
Which gets lightly stained- euchromatin or heterochromatin?
Euchromatin
What is the shape of heterochromatin?
Solenoid
Which type of chromatin is present in nucleolus?
Heterochromatin
What is the ribosomal factory of cell?
Nucleolus
Which animal has maximum number of chromosomes?
aulacanthus
Which plant has maximum number of chromosomes?
Ophioglossum
Which animal has minimum number of chromosome?
Ascaris
How many chromatonemata are present in a chromosome?
2
What is NOR?
Nuclear organizing region, aka secondary centromere
In which chromosomes is primary constriction located?
All chromosomes
Which nitrogenous bases are the chromosomal constrictions rich in?
Adenine and thymine
What is a v-shaped chromosome?
Metacentric chromosome
What is a L-shaped chromosome?
Sub-metacentric chromosome
What is a J-shaped chromosome?
Acrocentric chromosome
What is an i- shaped chromosome?
Telocentric chromosome
Polytene chromosomes are found in
Salivary glands of insects
WHat is the function of polytene chromosomes?
Synthesise proteins required for metamorphosis
Who discovered polytene chromosome?
Balbiani
Lamp brush chromosomes are found in
Oocytes of insects/amphibians
Which is bigger- giant chromosome or lampbrush chromosome?
Lamp-brush chromosome
What is the function of lamp-brush chromosomes?
Contain yolk producing genes
Which multiply faster- prokaryotes or eukaryotes?
Prokaryotes
Mesosomes occur in the form of
Vesicles, tubules and lamellae
Inclusion bodies in prokaryotes are bound to
They are free
Which part of cell envelope of plant cell helps in cell to cell recognition?
Cell wall
Can the primary cell wall grow?
Yes
What happens to the primary cell wall as it matures?
It diminishes
Are vacuoles a part of endomembrane system?
Yes
Where is the luminal compartment of cells?
Inside ER
Which ER is continuous with the nuclear membrane?
RER
The cis and trans face of golgi bodies are similar. True or false?
False
How do mitochondria divide?
Fission
How many chloroplasts are present in a mesophyll cell?
20 to 40
Which tubules connect grana?
Stroma lamellae
What does the ‘Svedberg’ unit signify?
Density and size
Which dyes stain the chromatin?
Basic dyes
Who coined the term ‘chromatin’?
Flemming
