Cell The Unit Of Life Flashcards
Unicellular organisms are capable of (i)………. (ii) ………..
independent existence
performing the essential functions of life
……………….first saw and described a live cell
Anton Von Leeuwenhoek
Robert Brown later discovered the……….
nucleus
1838,………….a………….botanist, examined a large number of plants
Matthias Schleiden
German
……………..(1839), a British………….studied different types of animal cells
Theodore Schwann
Zoologist
……………..concluded, based on his studies on plant tissues, that the presence of cell wall is a unique character of the plant cells
Theodore Schwann
Rudolf Virchow in ………..first explained that cells divided and new cells are formed from pre-existing cells aka………….
1855
Omnis cellula-e cellula
The………….is the main arena of cellular activities in both the plant and animal cells.
cytoplasm
Animal cells contain another……….bound organelle called………..which helps in cell division
non-membrane
centrosome
Mycoplasmas, the smallest cells, are only………µm in length while bacteria could be……..µm
0.3
3 to 5
human RBC are about……. µm in diameter
7.0
Assertion: Cells also vary greatly in their shape.
Reason: They may be disc-like, polygonal, columnar, cuboid, thread like, or even irregular
four basic shapes of bacteria are……/……/……/……
bacillus (rod like), coccus (spherical), vibrio (comma shaped) and spirillum (spiral).
Specialised differentiated form of cell membrane called……..is the characteristic of prokaryotes.
mesosome
These extensions are in the form of vesicles, tubules and lamellae.
They are essentially infoldings of cell membrane.
The cell envelope consists of a tightly bound three layered structure i.e., the outermost……..followed by the……and then the………
glycocalyx.
cell wall
plasma membrane
Assertion: Glycocalyx could be a loose sheath called the slime layer in some, while in others it may be thick and tough, called the capsule.
Glycocalyx differs in composition and thickness among different bacteria.
Plasma membrane of prokaryotes is similar structurally to that of the eukaryotes.
True or false?
True
Mesosome extensions are in the form of……/……/…….
vesicles, tubules and lamellae
Mesosomes help in……../……../……..They also help in………./……………. processes to increase the surface area of the plasma membrane and enzymatic content
cell wall formation, DNA replication and distribution to daughter cells
respiration, secretion
The filament is the longest portion and extends from the…………to the outside.
cell surface
Besides flagella, Pili and Fimbriae are also surface structures of the bacteria and play a role in motility
True or false
False
They don’t play any role in motility
Prokaryotic ribosomes is……….in size and are made of two subunits -……..&……….units which when present together form 70S
15 nm by 20 nm
50S and 30S
Reserve material 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 free in the cytoplasm,
True or false
True
Examples: phosphate granules, cyanophycean granules and glycogen granules.
Gas vacuoles are found in………/………./…………..bacteria.
blue green and purple and green photosynthetic
In some bacteria, they are known to help attach the bacteria to rocks in streams and also to the host tissues.
Guess me???
Fimbriae
Plant cells possess………/………/………which are absent in animal cells
cell walls, plastids and a large central vacuole
The human erythrocyte membrane has approximately …….per cent protein and ………per cent lipids.
52
40
Integral proteins are partially or totally buried in the membrane.
True or false
True
An improved model of the structure of cell membrane was proposed by Singer and Nicolson in ………… widely accepted as……….
1972
fluid mosaic model
Fluid nature of the membrane is also important from the point of view of functions like ……./……./……./……./…….etc.
cell growth, formation of intercellular junctions, secretion, endocytosis, cell division
Algae have cell wall, made of ……/……/……and minerals like…….
cellulose, galactans, mannans calcium carbonate
Secondary wall is formed on the outer side of the cell.
True or false??
False
It is formed on the inner (towards membrane) side of the cell
Functions of ……/……/……are not coordinated with the other components, these are not considered as part of the endomembrane system.
Mitochondria, chloroplast and peroxisomes
Camillo Golgi……..first observed …………stained reticular structures near the nucleus.
Who am I??
- densely
Golgi bodies
Golgi consist of many flat, disc-shaped sacs or cisternae of ….to…..diameter
0.5µm to 1.0µm
Golgi apparatus principally performs the function of………to be delivered either to the intra-cellular targets or secreted outside the cell.
packaging materials
membrane bound vesicular structures formed by the process of packaging in the Golgi apparatus.
Who am I?
Lysosomes
Vacuole is the…………bound space found in the cytoplasm.
membrane
contains water, sap, excretory product and other materials not useful for the cell.
In plant cells the vacuoles can occupy up to……….per cent of the volume of the cell
90
Amoeba the contractile vacuole is important for……. &……..
osmoregulation and excretion
Mitochondria sausage-shaped or cylindrical having a diameter of……….(average………) and length …………
0.2-1.0µm
0.5µm
1.0-4.1µm.
The membranes of mitochondria divide its lumen distinctly into two non aqueous compartments
True or false?
False
Two aqueous compartments
Inner compartment is filled with a dense homogenous/heterogenous substance called the matrix?
homogeneous
Assertion: Mitochondria is a semi autonomous organelle.
Reason: Matrix possesses single circular DNA molecule, a few RNA molecules, ribosomes (70S) and the components required for the synthesis of proteins
The chloroplasts are generally much larger then mitochondria
True or false
True
Based on the type of pigments plastids can be classified into……/……/……
chloroplasts, chromoplasts and leucoplasts.
In the chromoplasts fat……………/…………….pigments like carotene, xanthophylls and others are present
soluble. carotenoid
……………… are lens-shaped, oval, spherical, discoid or even ribbon-like organelles
Chloroplasts
Chloroplast size length……. and width …………
5-10µm
2-4µm
Chloroplasts number is variable with…….. in per cell chlamydomonas & ………… in mesophyll cells.
1
20-40
The space limited by the inner membrane of the chloroplast is called the………
stroma
The stroma of the chloroplast contains enzymes required for the synthesis of carbohydrates only.
True or false
False
Carbohydrates and proteins
Chloroplasts also contains small, ………..circular DNA molecules and ribosomes.
double-stranded
Ribosomes are granular structures first observed under the electron microscope as dense particles by George Palade in……
1953
S’ (Svedberg’s Unit) stands for…………it is indirectly a measure of ………. and size.
sedimentation coefficient
density
Centrosome is an organelle usually containing two cylindrical structures called……….
centrioles
Centrioles in centrosome are surrounded by………materials.
amorphous pericentriolar
The central part of the proximal region of the centriole is also……….and called the………
proteinaceous
hub
Material of the nucleus stained by the…….dyes was given the name chromatin by……..
basic
Flemming
Nuclear membrane is double and space between ie perinuclear space is………..nm.
10 to 50
Many membrane bound minute vesicles called microbodies that contain various enzymes, are present in both plant and animal cells.
True or false?
True
Eukaryotic cells have a variety of simple locomotory and cytoskeletal structures. Their genetic material is organised into chromosomes.
False
complex
Mesosome function
They help in cell wall formation, DNA replication and distribution to daughter cells.
They also help in respiration, secretion processes, to increase the surface area of the plasma membrane and enzymatic content.
A thin filamentous extensions from their cell membrane is called flagella.
False
Extension from cell wall
Statement 1: Also, the lipids are arranged within the membrane with the polar head towards the outer sides and the hydrophobic tails towards the inner part.
Statement 2: This ensures that the nonpolar tail of unsaturated hydrocarbons is protected from the aqueous environment
Statement 1 is correct and 2 is incorrect
Saturated hydrocarbons
Statement 1: The Golgi cisternae are concentrically arranged near the nucleus with distinct convex cis or the forming face and concave trans or the maturing face.
Statement 2: The cis and the trans faces of the organelle are entirely different, but interconnected.
Both are correct
The flip flop movement is shown by
Lipids and not the proteins also the lipids show it rarely
The presence of chloroplasts and mitochondria in eukaryotic cells is explained by the endosymbiotic theory.
True
This theory suggests that these organelles originated as free-living prokaryotic organisms that were engulfed by an ancestral eukaryotic cell. Over time, a symbiotic relationship developed, and the engulfed organisms evolved into organelles, providing essential functions such as energy production through photosynthesis in chloroplasts and cellular respiration in mitochondria.
Protoplast is ……..
A plant or bacterial cell without a cell wall
