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a) A small diagram of the cell highlighting the nucleus and endoplasmic reticulum. The nucleus is a large sphere in the cell and the endoplasmic reticulum is a series of webbed membranes just outside the nucleus. B) A micrograph showing these same structures. Outside the nuclear envelope are many lines labeled rough endoplasmic reticulum. A smaller set of lines is labeled mitochondrion overlaying part of the RER.
The rough endoplasmic reticulum is studded with ribosomes for the synthesis of membrane proteins (which give it its rough appearance).

Golgi apparatus

The Golgi apparatus was discovered within the endomembrane system in 1898 by Italian scientist Camillo Golgi (1843–1926), who developed a novel staining technique that showed stacked membrane structures within the cells of Plasmodium , the causative agent of malaria. The Golgi apparatus is composed of a series of membranous disks called dictyosomes, each having a single lipid bilayer, that are stacked together ( [link] ).

Enzymes in the Golgi apparatus modify lipids and proteins transported from the ER to the Golgi, often adding carbohydrate components to them, producing glycolipids, glycoproteins, or proteoglycans. Glycolipids and glycoproteins are often inserted into the plasma membrane and are important for signal recognition by other cells or infectious particles. Different types of cells can be distinguished from one another by the structure and arrangement of the glycolipids and glycoproteins contained in their plasma membranes. These glycolipids and glycoproteins commonly also serve as cell surface receptors.

Transport vesicles leaving the ER fuse with a Golgi apparatus on its receiving, or cis , face. The proteins are processed within the Golgi apparatus, and then additional transport vesicles containing the modified proteins and lipids pinch off from the Golgi apparatus on its outgoing, or trans , face. These outgoing vesicles move to and fuse with the plasma membrane or the membrane of other organelles.

Exocytosis is the process by which secretory vesicles (spherical membranous sacs) release their contents to the cell’s exterior ( [link] ). All cells have constitutive secretory pathways in which secretory vesicles transport soluble proteins that are released from the cell continually (constitutively). Certain specialized cells also have regulated secretory pathways , which are used to store soluble proteins in secretory vesicles. Regulated secretion involves substances that are only released in response to certain events or signals. For example, certain cells of the human immune system (e.g., mast cells) secrete histamine in response to the presence of foreign objects or pathogens in the body. Histamine is a compound that triggers various mechanisms used by the immune system to eliminate pathogens.

A small diagram of the cell outlining the Golgi complex which is a series of stacked membranes in the cell. A more detailed diagram shows the stacked membranes labeled cisternae and the inner regions of the stacks labeled lumen. Small spheres on the top are show transport vesicles from ER fuse with the cis face of the golgi. Small spheres on the bottom show newly formed secretory vesicles emerging from the trans face of the golgi. A micrograph shows the golgi in the cell as a stack of lines forming a semi-circle.
A transmission electron micrograph (left) of a Golgi apparatus in a white blood cell. The illustration (right) shows the cup-shaped, stacked disks and several transport vesicles. The Golgi apparatus modifies lipids and proteins, producing glycolipids and glycoproteins, respectively, which are commonly inserted into the plasma membrane.

Lysosomes

In the 1960s, Belgian scientist Christian de Duve (1917–2013) discovered lysosomes , membrane-bound organelles of the endomembrane system that contain digestive enzymes. Certain types of eukaryotic cells use lysosomes to break down various particles, such as food, damaged organelles or cellular debris, microorganisms, or immune complexes. Compartmentalization of the digestive enzymes within the lysosome allows the cell to efficiently digest matter without harming the cytoplasmic components of the cell.

Questions & Answers

difference between epidermophyton trichophyton and microsporum
Ankita Reply
plz answer the question
Iqra
epidermophyton type of fungi causes superficial and cutaneous mycoses trichophyton is also fungi type including parasitic varieties causes dermatophytosis microsporum is also type of fungi causes dermatophytosis.
Rana
ok
Iqra
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Ankita
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Rana
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Ankita
what is infectious
Fred Reply
Many poeple are die due to covid-19 virus
AMINU Reply
they become sick due to millions bacteria, fungi and some insects that make plants as their host.
charles Reply
what are microbes and what are their effects to humans
charles Reply
they are organism that cannot be seen with the naked eye
Angel
classify microorganisms.
Satarupa Reply
protozoa' bacteria' virus' algai' archea'
Cabdifitaax
protozoa
Ayesha
Thank you
Satarupa
bacteria,fungi, protozoa and virus
Angel
mutant having a requirement for a certain growth factor is called a(n)
Purushoth Reply
what is atome
Marie Reply
is the smallest part of any material that cannot be broken up by chemical means
Feisal
How does forest tree become sick
Emmanuel
Aseptate hyphae are seen in
lab Reply
yes
Ahmed
w
Ahmed
hello
Apdikrim
what is ADT
Feisal
hii
Salman
how does this work bro
Feisal
CHEMISTRY
Apdikrim
biology
Ahmed
I.m student
Ahmed
I.m question what is difference between arthropod and insect?
Ahmed
Arthropod is a large division of jointed-foot Invertebrates such as Insects, centipedes and others so Insect is a part of the division or the phylum
hilina
thanks
Ahmed
ur welcome
hilina
describe binary fission
Queen Reply
in which parent cell devides into two daughter cells
Iqra
single parent cell
Tean
who is the father of microbiology
Mary Reply
Antonie van Leeuwenhoek , he is father of microbiology and Louis Pasteur is father of modern microbioloy.
Arshad
Anton van leeuwenhoek ( He descovered bacteria in 1679)
Satarupa
what is the role of protein in virus genome
Rana Reply
what is microbiological
Apdikrim Reply
Science is a good Subject
AMINU Reply
yes it is
Madrine
what is amoeba
Joy Reply
a single celled organism with finger like extensions
janet
they could either be free living or parasitic
janet
is an organisms with no shape
Joy

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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