Cell- The basic unit of life Flashcards
the main arena for all activities to take place within the cell.
Cytoplasm
What are the cell organelles found in both eukaryotic and prokaryotic cells?
Ribosomes (no cell membrane)
Non membrane bound cell organelle present in animals which helps in cell division
Centriole
The smallest cells are
Mycoplasma
Largest isolated cells are
Ostrich eggs
Longest human cells are
Nerve cells
Only prokaryotes without a cell wall
Mycoplasma
The small DNA which are present in prokaryotes? What function do they perform
Plasmids-confer special phenotypic characters to the individual organisms. eg. resistance against antibiotics
Define Mesosomes
Infoldings or invaginations from the cell membrane into the cell.
Name the types of mesosomes
Vesicles, Tubules and lamellae
The cell wall in prokaryotes is made of how many layers
3- they are the glycocalyx, cell wall and the cell membrane
Give one function of the cell wall in prokaryotes
Gives shape and support, protects the cell and prevents it from bursting or collapsing in unfavourable conditions
Give some functions of mesosomes
cellular respiration, DNA replication and distribution to daughter cells, secretion processes, increases the surface area of the cell membrane
Chromatophores are present in
Cyanobacteria; contain pigments
The non- membranous cell organelle in animal cells except for ribosomes
centroid- helps in cell division
Ribosomes are associated with the……………….. of the cell
plasma membrane
What is the type of ribosome present in prokaryotes
70s which is made up of two sub units- 50s and 30s
Define polysomes
Several ribosomes attach to a single mRNA and form long chains of polysomes and polyribosomes.
Gas vacuoles are present in
Blue-green algae and purple and green bacteria
Give the composition of cell membrane
Phospholipids and cholesterol, proteins and carbohydrates
The ratio of proteins and lipids in human erythrocytes is
52% proteins and 40% lipids
Differentiate between the two types of proteins based on the ease of extraction
Integral proteins are buried partially or completely into the cell membrane while peripheral proteins lie on the surface
Fluid MosAIC MODEL WAS GIVEN BY
Singer and Nicholson
State the fluid mosaic model
THE QUASI FLUID NATURE OF THE LIPIDS ALLOWS THE LATERAL MOVEMENT OF PROTEINS ALONG THE OVERALL BILAYER. THIS MOVEMENT IS MEASURED AS ITS FLUIDITY.
fluid nature of the plasma membrane is important for
endocytosis, cell growth, cell division, formation of intercellular junctions and secretion
The algal cell wall is made of
mannans, galactans, cellulose and calcium carbonate
The plant cell wall is made of
Cellulose, hemicellulose, proteins and pectins
Cell wall in eukaryotes helps in
Gives shape and support to the cell, allows the cell to cell interactions, the barrier to undesirable macromolecules, protects the cell from mechanical damage and infection
Middle lamella is made of
Calcium pectate
Middle lamella is used in
glueing the neighbouring cells together
Plasmodesmata is?
Connects the cytoplasms of different cells together
The Endomembrane system is composed of
ER, Golgi apparatus, Lysosome, vacuoles
define the ER
a network or reticulum of tubules that lie scattered in the cytoplasm of the cell
The Er divides the intracellular space into
Luminal and extraluminal compartments
………………….. is present in the cells which are actively involved in secretions and synthesis.
RER
Secretion of steroidal hormones in animal cells is done by
SER
Define Golgi apparatus
Many flat disc-shaped structures or cisternae which are arranged parallel to each other
The COnvex face is called
Cis face
Golgi apparatus main function is
Packaging materials and sending them to intra cellular targets or outside the cell
What are synthesised in the golgi apparatus
glycolipids and glycoproteins
