MICR 2420 Lecture 4: MICR 2420 Lecture 4

56 views15 pages

mauvemacaw936

27 Jun 2018

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

What is an archaea?

These microbes (archaea; singular archaeon) are prokaryotes, they have no cell nucleus

or any other membrane-bound organelles in their cells

Archaea is derived from the Greek word archaios, meaning “ancient” or “primitive”

Despite the morphological similarity to bacteria, archaea possess genes and several

metabolic pathways that are more closely related to those of eukaryotes, notably the

enzymes involved in transcription and translation

Archaea have more complex RNA polymerases than Bacteria, similar to Eucarya

Unlike bacteria, archaea cell walls do not contain peptidoglycan

Archaea have different membrane lipid bonding from bacteria and eukarya.

Archaea found in soil and water habitats in symbiosis with plants and animals and in

extreme environments

No Archaea is yet to known to cause diseases, but archaea do interact with our innate

immune system

Archaea look like bacteria but are NOT bacteria

They are as closely related to bacteria as we are!

Although they can be found in many different environments, many species live under

extreme conditions

Overall, they grow within a wider range of temperature and other environmental

conditions than either bacteria or eukaryotes

Archaeal cell membrane traits

Cell membranes very different from bacteria & eukaryotes

Archaea use L-glycerol linked to side chains using ether links

Bacteria use D-glycerol linked to side chains using ester links

oEther links are much more stable than ester links

oL- and D-forms of glycerol have similar properties but require completely

different sets of enzymes for synthesis

Isoprene subunits link together to form isoprenoid (imparts membrane stability)

-Overall lipid is diphytanylglycerol diether

find more resources at oneclass.com

Unlock document

This preview shows pages 1-3 of the document.
Unlock all 15 pages and 3 million more documents.

Already have an account? Log in

In some extremophiles, the ends of the side chains link up covalently with each other or

to other lipids, or even form a cyclic structure

Strengthens the membrane considerably

Allows some of the more weird Archaeal shapes(e.g.squares!)

Two pairs of lipid chains cross linked across the membrane form a tetraether

Archaeal lipids lack the fatty acids found inBacteria and Eukaryotes and instead have

side chains composed of repeating units of isoprene

In some Archaea, the lipid’s methyl branches cyclize, forming cyclopentane rings

oCyclopentane rings strengthen membranes at high temperature

find more resources at oneclass.com

Unlock document

This preview shows pages 1-3 of the document.
Unlock all 15 pages and 3 million more documents.

Already have an account? Log in

Archaeal cell wall

The cell wall of some methanogens is actually very similar to that of bacteria

Instead of peptidoglycan, a molecule, pseudopeptidoglycan (pseudomurein) is used

oInstead of N-acetyl muramic acid, there is N-acetylalosaminuronic acid

• Pseudopeptidoglycan is not affected by either lysozyme or penicillin

find more resources at oneclass.com

Unlock document

This preview shows pages 1-3 of the document.
Unlock all 15 pages and 3 million more documents.

Already have an account? Log in

Document Summary

These microbes (archaea; singular archaeon) are prokaryotes, they have no cell nucleus or any other membrane-bound organelles in their cells. Archaea is derived from the greek word archaios, meaning ancient or primitive . Despite the morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably the enzymes involved in transcription and translation. Archaea have more complex rna polymerases than bacteria, similar to eucarya. Unlike bacteria, archaea cell walls do not contain peptidoglycan. Archaea have different membrane lipid bonding from bacteria and eukarya. Archaea found in soil and water habitats in symbiosis with plants and animals and in extreme environments. No archaea is yet to known to cause diseases, but archaea do interact with our innate immune system. Archaea look like bacteria but are not bacteria. They are as closely related to bacteria as we are!

Related Questions

1) Protists are eukaryotes and possess which of the following characteristics? (select ALL correct answers)

A	are found only in the digestive tracts of animals

B	all have flagella

C	a nuclear envelope

D	reproduction by binary fission

2) Protists are eukaryotic organisms that are often unicellular, but some species are multicellular, and some are more closely related to ___ than they are to other protist lineages.

archaea

aliens

C	plants, animals, or fungi

bacteria

3) In a protist lifecycle where do you expect meiosis to occur?

A	just prior to fertilization

B	in a diploid cell

C	in a haploid cell

D	in the gametes

QUESTION 1

Which of the following statements about the bacterial cytoplasmic membrane is false?

	a.	It resists attachment of the bacterial chromosome to its inner surface.
	b.	It contains a protein complex that drives ATP synthesis.
	c.	It is asymmetric.
	d.	It consists of relatively equal amounts of phospholipids and proteins.

1 points

QUESTION 2

Which of the following statements regarding Mycobacteria is false?

	a.	The genome has relatively low Guanine (G) and Cytosine (C) content.
	b.	The cytoplasmic membrane is surrounded by a polymer (peptidoglycan) consisting of alternating N-Acetylglucosamine (NAG) and N-Acetylmuramic (NAM) acid units.
	c.	It infects approximately one-third of the global human population.
	d.	It has a Gram-positive cell wall with an additional waxy lipid layer of mycolic acid.

1 points

QUESTION 3

Which of the following outer membrane porins enables Mycobacteria to adapt to acidic and intracellular environments, and shows homology to outer membrane porin A?

	a.	OmpATb.
	b.	OmpA.
	c.	MspA.
	d.	Lipid A.

1 points

QUESTION 4

Based on your understanding of bacterial membranes, which of the following is not likely to be found in an E. coli outer membrane?

	a.	Membrane-anchored enzymes.
	b.	Mycolic acid.
	c.	Lipopolysaccharide.
	d.	Porin channels.

1 points

QUESTION 5

Based on the conclusions of this paper, which of the following statements would the author most likely disagree with?

	a.	Some archaeon do not contain all of the genes essential for life.
	b.	The membrane structures of prokaryotes show far greater diversity than those of eukaryotes.
	c.	As demonstrated in this definitive report, scientists have a great understanding of the majority of basic functions and evolution of bacterial membranes.
	d.	The outer membrane (and its associated components) of archaea, Gram-negative bacteria, and Gram-positive bacteria likely evolved independently of one another.

1 points

QUESTION 6

Which of the following is not true for Gram-negative, acid-fast, and archaeal membranes?

	a.	They modify their lipid content in response to environmental changes.
	b.	They have co-evolved the same outer membrane composition and structure.
	c.	They all have a cytoplasmic membrane.
	d.	Membrane transport proteins regulate nutrient uptake and waste removal.

1 points

QUESTION 7

Compared to Mycobacteria, Gram-negative bacterium contain:

	a.	More mycolic acid.
	b.	Pores of increased length.
	c.	Less peptidoglycan.
	d.	50-fold-lower numbers of porins.

1 points

QUESTION 8

Archaea are found to survive in strongly acidic lakes compared to bacteria and Eukaryotes. Which of the following supports this claim according to the study?

	a.	The presence of L-glycerol ether linked lipids in Archaea membranes.
	b.	The presence of D-glycerol ether linked lipids in Archaea membranes.
	c.	The presence of L-glycerol ester linked peptidoglycans in Archaea membranes.
	d.	The presence of L-glycerol ester linked lipids in Archaea membranes.

1 points

QUESTION 9

Based on your understanding of the symbiotic relationship between Nanoarchaeum equitans and Ignicoccus, which of the following below is not true?

	a.	The membrane lipids of N. equitans are synthesized by Ignoccocus.
	b.	In exchange for membrane lipids, N. equitans provide Ignicoccus with many essential cytoplasmic enzymes.
	c.	N. equitans lack enzymes capable of catalyzing lipid biosynthesis.
	d.	Intraperiplasmic vesicles produced by Ignicoccus allow for lipid transfer to N. equitans.

1 points

QUESTION 10

What is the role of hydrogen bonds in bacteria, as mentioned in the article?

	a.	They mediate transmembrane electron flow.
	b.	They mediate lipid biosynthesis.
	c.	They help to stabilize the cytoplasmic membrane.
	d.	They are responsible for the selective permeability of the cytoplasmic membrane.

1.This week, you will be conducting Gram stains of bacteria.Which of the following statements are true? (Mark all thatapply)

		Gram-negative bacteria do not stain purple because they do nottake-up crystal violet or iodine
		The peptidoglycan in the walls of Gram-positive bacteria bindsto the crystal violet stain more easily than walls of Gram-negativebacteria do
		Gram-positive bacteria have cell walls with a thickerpeptidoglycan layer than walls of Gram-negative bacteria
		Gram-negative bacteria do not stain purple, because their cellwall structure allows purple-colored iodine-dye complexes to washout of the cells more easily than the cell wall structure ofGram-positive bacteria does
		Gram-negative bacteria have an outer membrane (outside thepeptidoglycan layer in their wall) that Gram-positive bacterialack

What evidence is used to inform our understanding ofrelationships among species? (mark all that apply)

		Biochemical similarities between existing species
		Fossils
		Morphological similarities between existing species (presence ofhair, backbones, etc.)
		DNA sequences and molecular clocks

For each of the groups of organisms below, indicate whether theybelong in (A.) Archaea, (B.) Bacteria, or (C.) Eukarya

- A. B. C.	Methanogens (prokaryotes that produce methane)
- A. B. C.	Gram-positive bacteria
- A. B. C.	Fungi
- A. B. C.	Animals
- A. B. C.	Cyanobacteria
- A. B. C.	Green algae
- A. B. C.	Red algae
- A. B. C.	Amoebas
- A. B. C.	Thermophiles (prokaryotes of hydrothermal vents)
- A. B. C.	Plants
- A. B. C.	Free-living relatives of mitochondria
- A. B. C.	Single-celled organisms with a circular strand of DNA, without anuclear envelope and without peptidoglycan in their cell walls

Select all true statements about the relative diversity ofdifferent groups of organisms from among the followingstatements:

		There are more species of plants on Earth than species ofmolluscs
		There are more plant species on Earth than mammal species
		There are more species of plants on Earth than species offungi
		There are more species of fungi on Earth than mammal species
		There are more species of plants on Earth than species ofarthropods
		There are more flatworm species on Earth than mammal species

beigegerbil183

MICR 2420 Lecture 4: MICR 2420 Lecture 4

Document Summary

Get access

Related Documents

MICR 2420 Lecture Notes - Lecture 5: Desulfurococcales, Crenarchaeota, Cyclopentane

MICR 2420 Lecture Notes - Lecture 3: Pyrococcus Furiosus, Sulfate-Reducing Microorganisms, Ferroplasma

MICR 2420 Study Guide - Midterm Guide: Protist, Protozoa, Peptidoglycan

Related Questions