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Chloroplasts

Plant cells and algal cells contain chloroplasts , the organelles in which photosynthesis occurs ( [link] ). All chloroplasts have at least three membrane systems: the outer membrane, the inner membrane, and the thylakoid membrane system. Inside the outer and inner membranes is the chloroplast stroma , a gel-like fluid that makes up much of a chloroplast’s volume, and in which the thylakoid system floats. The thylakoid system is a highly dynamic collection of folded membrane sacs. It is where the green photosynthetic pigment chlorophyll is found and the light reactions of photosynthesis occur. In most plant chloroplasts, the thylakoids are arranged in stacks called grana (singular: granum), whereas in some algal chloroplasts , the thylakoids are free floating.

The cholorplast is shown as an oval structure with an outer membrane. The inner membrane folds into pancake like stacks called grana (stacks of thylakoids). One individual stack from the grana is called a thylakoid. The space inside the thylakoid is called the thylakoid lumen. The aqueous fluid outside the thylakoids but inside the inner membrane is the stroma. The space between the inner and outer membranes is the intermembrane space.
Photosynthesis takes place in chloroplasts, which have an outer membrane and an inner membrane. Stacks of thylakoids called grana form a third membrane layer.

Other organelles similar to mitochondria have arisen in other types of eukaryotes, but their roles differ. Hydrogenosomes are found in some anaerobic eukaryotes and serve as the location of anaerobic hydrogen production. Hydrogenosomes typically lack their own DNA and ribosomes. Kinetoplasts are a variation of the mitochondria found in some eukaryotic pathogens. In these organisms, each cell has a single, long, branched mitochondrion in which kinetoplast DNA, organized as multiple circular pieces of DNA, is found concentrated at one pole of the cell.

Many protozoans, including several protozoan parasites that cause infections in humans, can be identified by their unusual appearance. Distinguishing features may include complex cell morphologies, the presence of unique organelles, or the absence of common organelles. The protozoan parasites Giardia lamblia and Trichomonas vaginalis are two examples.

G. lamblia , a frequent cause of diarrhea in humans and many other animals, is an anaerobic parasite that possesses two nuclei and several flagella. Its Golgi apparatus and endoplasmic reticulum are greatly reduced, and it lacks mitochondria completely. However, it does have organelles known as mitosomes , double-membrane-bound organelles that appear to be severely reduced mitochondria. This has led scientists to believe that G. lamblia’ s ancestors once possessed mitochondria that evolved to become mitosomes. T. vaginalis , which causes the sexually transmitted infection vaginitis, is another protozoan parasite that lacks conventional mitochondria. Instead, it possesses hydrogenosomes , mitochondrial-related, double-membrane-bound organelles that produce molecular hydrogen used in cellular metabolism. Scientists believe that hydrogenosomes, like mitosomes, also evolved from mitochondria. N. Yarlett, J.H.P. Hackstein. “Hydrogenosomes: One Organelle, Multiple Origins.” BioScience 55 no. 8 (2005):657–658.

Plasma membrane

The plasma membrane of eukaryotic cells is similar in structure to the prokaryotic plasma membrane in that it is composed mainly of phospholipids forming a bilayer with embedded peripheral and integral proteins ( [link] ). These membrane components move within the plane of the membrane according to the fluid mosaic model. However, unlike the prokaryotic membrane, eukaryotic membranes contain sterols , including cholesterol, that alter membrane fluidity. Additionally, many eukaryotic cells contain some specialized lipids, including sphingolipids, which are thought to play a role in maintaining membrane stability as well as being involved in signal transduction pathways and cell-to-cell communication.

Questions & Answers

Explain Mould
Chinenye Reply
Explain mycoses and it's classification
Chinenye
why do we have hiccups?
Manisha Reply
shakey diaphragm
Curlisse
The antibody binding site is formed primarily by:
Asalla Reply
How many types of MICROORGANISMS do we have?
Hope Reply
Hello friends
Hope
What's pathogenesity
Usman Reply
something that causes disease
Anietie
who is the father of microbiology?
Hope
no it is not it also dealt withe fermentation techniques, downstream processing of isolated products etc
Ramchandra Reply
hy
Abdul
hy
Roshan
you from
Abdul
I'm from Bangalore, India
Shanu
in banglore
Prabhat
what group is Indian
Abdul
I'm from pune
Vitthal
ok
Abdul
Why scientists is not studies the drungs or vaccines of a virus, based on common characterstics of virus as living and non-living organisms?
demisew
what are the examples of viruses and their causing agent
kolawole Reply
coronavirus in the family of Coronaviridae and the causing agent is common cold where it spread easily compared to hot region.you can correct me if I am wrong.
nyakaraitta
👍
Puja
what
nkechi
okay there are major 3 groups (1.Enterovirus=poliovirus, cocksakievirus A&B,echovirus,endovirus etc causing poliomyelities,meningitis, fever,respiratory disease, acute hemorrhagic conjunctivitis, 2.Hepatitis virus- infectious hepatitis , 3.Rotavius incl.coronavius =vomiting, diarrhoea and common co
nyakaraitta
isthe another virus are coronaviridae
anuush
Hai Puja
Shanu
g
Abdul
corona virus is not dangerous but not care is very dangerous..............
Abdul
👍
Puja
he means if we take care we will not be infected
abel
yeah
Abdul
for the question thing first let's classify viruses then it would be easier to deal with zem
abel
Where you all from?
Shanu
Pakistan
Abdul
what are five elements that are needed for bacteria to grow?
Florence
proper acidity (ph)
Abdi-fatah
salt level
Abdi-fatah
Temperature
Bejide
osmotic pressure,oxygen,light
abel
but zey are not only five n we can classify zem as physical and chemical
abel
air in hydrogen and carbon and niterogin
Abdul
1. Possible complications and outcomes for cutaneous anthrax:
Firoj Reply
chlamydia can it be viral disease?
nyakaraitta Reply
noh
Vitthal
what is microbiology
Sohel Reply
is the study of tiny organisms with the use of microscopes
Bejide
Is the study of microorganisms
Usman
is the biological science of identification and charaterization of micro organisms surrounding the environment
Jojo
what are the major groups of archae bacteria
Brian Reply
methanogens, halophiles, thermophiles
Mahalakshmi
Right, mali
vivek
yeah!!
Mahalakshmi
yes
nyakaraitta
right
Jojo
how can get information
Raage Reply
how i study microbiology
Raage
By Reading About It
Rajat
quickest form
Raage
why do our brain needs glucose?
Bijay Reply
b/c our brain works glucose as the other body use insulin
Cabdi
of course why do hairs obtain nutrients yet there is no blood?
nyakaraitta
can I get a diagram of paramicium
nyakaraitta
what is the meaning of the term microbiology
Mary Reply
 study of all living organisms that are too small to be visible with the naked eye.
Nnamdi
yahh it right
Stavan
wow lovely
Psalm
Well said.
Shanu
study of microscopic organism like protozoa, bacteria, fungi, algea ,viruses betc
Dr
what are the career opportunities in microbiology
Anietie
I don't understand the explanation
Nancy Reply
ok
Cabdi
virus can also culture?
anuush
ya same doubt.. virus can also culture?
Prabhat
prabhat explain More
Prince
yes we can culture virus. virus culture is a laboratory test in which samples are placed with a cell type that the virus being tested for is able to infect.
Feby
the topic is telling us on how the first microscope is been invented by van Lee...., & his own still remains the best although he's was a simple one with one lens while the compound one that was invented by Hooke with two lenses is the one commonly used now.
Esumeh
sorry! Hooke didn't invent it rather he used it in the writing of his book .
Esumeh
what is microbiology
Sohel
microbiology is the study of microrganisms (unicellular,multicellular) which can be seen under the microscope
Andrre

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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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