Cells & Tissues Flashcards
what is magnification?
increase in apparent size of an object when seen under microscope.
what is resolution?
minimum distance between two point on an object that can be distinguished as two separate entities.
what is a microscope?
a device used for the magnification of the sample
who developed first compound microscope?
Zacharias Janssen 1595
resolution of human eye is ______.
0.1mm
with the help of ______, resolution can be increased.
lenses
types of microscope?
2 LM EM
LM’s magnification power?
1500X
LM’s resolving power?
0.2 micrometer
what is micrograph?
a photograph taken through a microscope.
what is LM
A light microscope works by passing visible light through a specimen. It uses two glass lenses i.e. eyepiece & objective.
EM’s magnification power?
upto 1,000,000X
EM’s resolving power?
0.2nm
what is EM?
what is TEM?
specimens are cut into extremely thin sections before studying
TEM is used to study the internal cell structure
why EM can’t be used to study life processes?
vacuum chamber
what is SEM?
what did Aristotle contributed to the formation of cell theory?
he presented the idea that all animals and plants are somehow related.
who described cells at first?
British scientist Robert Hooke in 1665.
who saw living cells for the first time?
Dutch naturalist Antonie van
Leeuwenhoek. He observed tiny organisms (from pond water) under his microscope and called
them as “animalcules”.
who discovered the first nucleus?
British botanist Robert Brown
1831
what did Matthias Schleiden contribute to the cell theory?
He stated that all plants are aggregates of individual cells which are fully independent.
who was Theodor Schwann?
1839, a German zoologist
he reported that all animal tissues are also composed of individual cells.
who was Rudolf Virchow?
1855, a German physician, proposed an important extension of cell theory. He proposed that all living cells arise from pre-existing cells (“Omnis cellula e celula”).
who was Louis Pasteur?
In 1862, Louis Pasteur provided experimental proof that microorganisms i.e. bacteria could be be produced from existing bacteria.
what does modern cell theory state?
- All organisms are composed of one or more cells.
- A cell is the structural and functional unit of organisms.
- Cells arise only by divisions in previously existing cells.
who first proposed cell theory?
Schleiden and Schwann proposed cell theory in its initial form.
how many types of eukaryotic cells are there?
2
animal cell & plant cell
what are organelles?
small, subcellular bodies with specific structure and function present within the cytoplasm of a cell.
only eukaryotes have cell membranes. false/true
false
All prokaryotic and eukaryotic cells have a thin and elastic cell membrane covering the cytoplasm.
types of proteins in plasma membrane?
3
integral
peripheral
glycoproteins
How does the cell membrane contribute to maintaining the internal composition of a cell?
The cell membrane is selectively permeable, which means it allows only specific molecules to enter or exit the cell.
cholesterol in cell membrane is used for ______________.
retaining the fluidity, it is present between the phospholipids.
what is cell membrane structure represented by?
fluid mosaic model
what substance are allowed to enter & leave plasma membrane?
oxygen food and water
waste products
where are proteins present in membrane?
protein molecules are embedded in lipid bilayer.
chemically, cell membrane is mainly composed of _______________.
proteins and lipids with
small quantities of carbohydrates.
functions of cell membrane?
structural support
selective permeability
cellular communication
explain fluid mosaic model?
According to this model, there is a lipid bilayer in which the protein molecules are
embedded.
The lipid bilayer gives fluidity and elasticity to membrane. Small amounts of carbohydrates are also found in cell membrane. In eukaryotic cells cholesterol is also present in lipid bilayer.
components of plasma membrane?
Phospholipids
cholesterol
proteins
small quantity of carbs
cell membrane is _________ permeable.
selectively
how many and what are the fundamental types of biomolecules?
plcn
Painted Lilies Create Nature
all of ‘em are macromolecules
carbohydrates, lipids, nucleic acids, and proteins.
what is the fluid inside the nucleus called?
nucleoplasm
why is nucleus in plant cell shifted to side?
due to the formation of large central vacuole.
Nuclear envelope contains many small pores that enable it to act as a ______________.
semi-permeable membrane.
nucleoli
singular: nucleolus
staining region in nucleus is called ____________.
nucleolus/nucleoli (plural)
treated with a stain or dye to enhance the visibility of certain structures.
function of nucleolus
ribosomal RNA are formed and assembled as ribosomes.
in which phase chromatin condenses to form chromosome?
prophase
chromosomes are composed of _________.
DNA & proteins
what is a nucleus?
Eukaryotic cells have a nucleus, which is a double-membraned organelle that contains the cell’s DNA.
The nucleus is located in the center of animal cells, but it may be pushed to the side in plant cells due to the large central vacuole.
The nuclear envelope is the double membrane that surrounds the nucleus. It contains many pores that allow molecules to pass between the nucleus and the cytoplasm.
The nucleoplasm is the fluid inside the nucleus. It contains nucleoli, chromosomes, and other proteins.
Nucleoli are dark spots in the nucleoplasm that are the site of ribosome production.
Chromosomes are thread-like structures made of DNA and proteins. They are only visible during cell division.
Prokaryotic cells do not have a nucleus. Their DNA is in the cytoplasm in the form of a single chromosome.
how does a prokaryotic cell look like?
don’t contain prominent nucleus. Their chromosome is made of DNA only
and is submerged in cytoplasm.
__________ controls all activities of a cell.
nucleus
what is the difference between cell membrane and nuclear envelope?
The nuclear envelope is a double membrane that surrounds the nucleus. It is made up of two lipid bilayers.
The cell membrane is a single membrane that surrounds the entire cell. It is made up of a lipid bilayer
what is a cytoplasm?
the semi-viscous and semi-transparent substance between plasma membrane and nuclear envelope.
name a biochemical reaction that happens in the cytoplasm?
Glycolysis (breakdown of glucose during cellular respiration).
why does cytoplasm contain water?
It contains water in which many organic molecules (proteins,
carbohydrates, lipids) and inorganic salts are completely or partially dissolved.
Cytoplasm provides ______ for the proper functioning of ________ and also acts as the site for various ______________.
space
organelles
biochemical (metabolic) reactions.
ribosomes are found in both prokaryotic and eukaryotic cell. T/F
True
Eukaryotic ribosomes are slightly smaller/larger than prokaryotic ones.
larger
in what forms ribosomes are found?
2
1. attached with ER
2. freely dispersed in cytoplasm
what are ribosomes?
are ribosomes bounded by a membrane?
no
what are ribosomes made of?
equal amounts of rRNA & proteins
Ribosomes are the sites of _______________.
protein synthesis
what is ER?
a network of interconnected channels that extends from cell membrane to nuclear envelope.
function of RER?
protein synthesis
function of SER?
important role in lipid formation
Detoxification of drugs in the liver
it forms vesicles to transport large molecules from one part of a cell to the other.
which one has no ribosomes attached with it? SER or RER?
SER
that’s why it’s called smooth.
who discovered the Golgi complex?
Italian physician Camillo Golgi
what is lumen?
inner open spaces of the cisternae in Golgi apparatus.
what is Golgi apparatus?
series of flattened sacs formed of membranes. It modifies molecules coming
from rough ER and packs them into small membrane bound sacs called Golgi vesicles. These sacs can be transported to various locations in cell or to its exterior, in the form of secretions.
Vesicles are seen at the ________ of the _______of Golgi complex.
stack (cisternae)
edges
explain the process when molecule go from RER into Golgi complex?
The vesicles containing molecules bud off from the ER and carry their cargo to the Golgi apparatus.
explain the process when molecules enter the Golgi complex?
The molecules enter the Golgi apparatus after being transported from the rough ER. As the molecules move through the Golgi cisternae, they undergo modifications, such as having sugars added to them or having other molecules attached. These modifications are essential for the molecules to become fully functional.
explain the process when the molecule is done being modified and ready for departure. (from Golgi complex)
Once the molecules are modified and sorted within the Golgi complex, they are packaged into vesicles. These vesicles bud off from the edges of the Golgi cisternae, containing the modified molecules.
explain the process when the vesicle is transported to its destination.
These vesicles transport the molecules to different destinations within or outside the cell, depending on their type and function. Some vesicles may carry molecules to lysosomes, which are organelles responsible for digesting waste and cellular debris. Some Golgi vesicles, known as secretory vesicles, move towards the cell membrane in the form of secretions.
what are lysosomes?
Lysosomes are small, spherical organelles enclosed by a single lipid bilayer membrane. Lysosomes contain various active hydrolytic enzymes which breakdown molecules.
why is a membrane important in lysosome?
prevents the enzymes and other molecules within the lysosome from leaking into the rest of the cell.
is mitochondria double or single membrane bounded structure?
double membrane bounded
mitochondria is only found in eukaryotes. T/F
True
The outer membrane of a mitochondrion is _________ but the inner membrane forms many __________,
called _______, singular (______)
smooth
infoldings
cristae
crista
why are infoldings in mitochondria important?
to increase the surface area of inner membrane on which membrane-bound reactions can take place, so more ATP will be released.
The ribosomes of mitochondria are more similar
to ______________ than to ________________.
bacterial ribosomes
eukaryotic ribosomes
what is matrix and function of it?
mitochondrial solution where all necessary enzymes are for the production of ATP.
what is mitochondria?
Mitochondria are spherical, elongated tiny, double membrane-bounded structures found only in eukaryotes.
These are the sites of aerobic respiration, and are the major energy production centers.
Mitochondria have their own _________________.
ATP full form?
DNA and ribosomes.
Adenosine Triphosphate
what is the function of centrioles?
to help in the formation of spindle fibers during cell division.
In some cells, centrioles are involved in the formation of cilia and flagella.