All cells share similarities in their basic macromolecular components and chemical reactions. They all use nucleic acids like DNA and RNA to store and access genetic information. Proteins, which are polymers of amino acids, serve as enzymes to catalyze cellular reactions. Lipids form cellular membranes and carbohydrates serve structural and energy roles. The same condensation and hydrolysis reactions are used to form and break down these macromolecules in all organisms, reflecting their shared evolutionary origin.
After reading the text, please describe the 3 types of chemical bond.docxMARK547399
After reading the text, please describe the 3 types of chemical bonds and the four important macromolecules. In addition, describe the types of cells you know and give us a brief description of the cell structure.
TEXT:
The large molecules necessary for life that are built from smaller organic molecules are called biological
macromolecules
. There are four major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids), and each is an important component of the cell and performs a wide array of functions. Combined, these molecules make up the majority of a cell's mass. Biological macromolecules are organic, meaning that they contain carbon. In addition, they may contain hydrogen, oxygen, nitrogen, phosphorus, sulfur, and additional minor elements.
Carbon
It is often said that life is "carbon-based." This means that carbon atoms, bonded to other carbon atoms or other elements, form the fundamental components of many, if not most, of the molecules found uniquely in living things. Other elements play important roles in biological molecules, but carbon certainly qualifies as the "foundation" element for molecules in living things. It is the bonding properties of carbon atoms that are responsible for its important role.
Carbon Bonding
Carbon contains four electrons in its outer shell. Therefore, it can form four covalent bonds with other atoms or molecules. The simplest organic carbon molecule is methane (CH4), in which four hydrogen atoms bind to a carbon atom (
Figure 13
).
However, structures that are more complex are made using carbon. Any of the hydrogen atoms could be replaced with another carbon atom covalently bonded to the first carbon atom. In this way, long and branching chains of carbon compounds can be made (
Figure 14a
). The carbon atoms may bond with atoms of other elements, such as nitrogen, oxygen, and phosphorus (
Figure 14b
). The molecules may also form rings, which themselves can link with other rings (
Figure 14c
). This diversity of molecular forms accounts for the diversity of functions of the biological macromolecules and is based to a large degree on the ability of carbon to form multiple bonds with itself and other atoms.
Carbohydrates
Carbohydrates
are macromolecules with which most consumers are somewhat familiar. To lose weight, some individuals adhere to "low-carb" diets. Athletes, in contrast, often "carb-load" before important competitions to ensure that they have sufficient energy to compete at a high level. Carbohydrates are, in fact, an essential part of our diet; grains, fruits, and vegetables are all natural sources of carbohydrates. Carbohydrates provide energy to the body, particularly through glucose, a simple sugar. Carbohydrates also have other important functions in humans, animals, and plants.
Carbohydrates can be represented by the formula (CH2O)
n
, where
n
is the number of carbon atoms in the molecule. In other words, the ratio of carbon to hydrogen.
Carbohydrates are the sugars, starches and fibers found in fruits, grains, vegetables and milk products. Though often maligned in trendy diets, carbohydrates — one of the basic food groups — are important to a healthy diet.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
2. Cells as chemical reactors
Living organisms obey the laws of
chemistry and physics
Can think of cells as complex chemical reactors in
which many different chemical reactions are
proceeding at the same time
All cells more similar then different if
looked at on the inside!
Strip away the exterior and we see that all cells need
to accomplish similar tasks and in a broad sense they
use the same mechanisms (chemical reactions)
Reflects a singular origin of all extant living things!
3. Similarities among all types of cells
All cells use nucleic acids (DNA) to store information
RNA viruses, but not true cells
(incapable of autonomous replication)
All cells use proteins as catalysts (enzymes) for
chemical reactions
A few examples of RNA based enzymes, which may reflect
primordial use of RNA
All cells use lipids for membrane components
Different types of lipids in different types of cells
All cells use carbohydrates for cell walls (if present),
recognition, and energy generation
All cells use nucleic acids (RNA) to access
stored information
4. Macromolecules
Large Molecules
Macromolecules are formed when
monomers are linked together to form
longer chains called polymers.
The same process of making and breaking
polymers is found in all living organisms.
5. Consider some generic monomers with OH groups on their ends.
These monomers can be linked together by a process called
dehydration synthesis (also called a condensation reaction) in
which a covalent bond is formed between the two monomers while
a water molecule is also formed from the OH groups.
This reaction is catalyzed by a polymerase enzyme.
This same type of condensation reaction can occur to form many
kinds of polymers, from proteins to carbohydrates, nucleic acids to
triglycerides.
Condensation Reaction
6. Hydrolysis Reactions
Polymers of all sorts can be broken apart
by hydrolysis reactions. In hydrolysis the
addition of a water molecule (with the help
of a hydrolase enzyme) breaks the
covalent bond holding the monomers
together.
7. Macromolecules
Biotechnology often concerned with the
manipulation of cells through the manipulation
of the macromolecules contained within those
cells
DNA
Proteins
Lipids & Carbohydrates (indirectly)
8. Biologically important macromolecules are
“polymers” of smaller subunits
Created through condensation reactions
Carbohydrates : simple sugars
Lipids : CH2 units
Proteins : amino acids
Nucleic acids : nucleotides
Macromolecule Subunit
9. Where do the subunits come from?
All cells need a source of the atomic components of the
subunits
(C, O, H, N, P, and a few other trace elements )
Some cells can synthesize all of the subunits given these
atomic components and an energy source
Some cells can obtain these subunits from external sources
Some cells can convert other compounds into these subunits
We will discuss further in section on metabolism and cell
growth
10. Carbohydrates
All have general formula CnH2nOn (hydrates
(H2O) of carbon)
A variety of functions in the cell
Large cross-linked carbohydrates make up the
rigid cell wall of plants, bacteria, and insects
In animal cells carbohydrates on the exterior
surface of the cell serve a recognition and
identification function
A central function is energy storage
and energy production !
11. Carbohydrates
Carbohydrates are always composed of
carbon, hydrogen and oxygen molecules
Monosaccharides typically have five or
six carbon atoms.
Monosaccharides can, such as the ribose
and deoxyribose of RNA and DNA, can
serve very important functions in cells.
12. Carbohydrates
Condensation reactions form covalent
bonds between monosaccharides, called
glycosidic linkages.
Monosaccharides are the monomers for
the larger polysaccharides.
Polysaccharides play various roles, from
energy storage (starch, glycogen) to
structure (cellulose).
13. Carbohydrates
Cell structure:
Cellulose, LPS, chitin
Cellulose in plant cell walls Lipopolysaccharides (LPS)
in bacterial cell wall
Chitin in exoskeleton
15. Carbohydrate Structure
Complex carbohydrates built from simple sugars
Most often five (pentose) or six (hexose) carbon
sugars
Numerous –OH (hydroxy) groups can form many
types of “cross links”
Can result in very complex and highl;y cross
linked structures ( cellulose, chitin, starch, etc.)
17. Carbohydrate Structure
Example of two hexoses
Glucose Galactose
What’s the difference? Both are C6H12O6
They are isomers of one another!
Same formula, but different structure (3D-shape).
18. Carbohydrate Structure
Monosacharides can be joined to one another to form
disaccharides, trisaccharides, ……..polysaccharides
Saccharide is a term derived from the Latin for sugar (origin = "sweet sand")
Carbohydrates classified according to the number of
saccharide units they contain.
A monosaccharide contains a single carbohydrate, over
200 different monosaccharides are known.
A disaccharide gives two carbohydrate units on
hydrolysis.
An oligosaccharide gives a "few" carbohydrate units on
hydrolysis, usually 3 to 10.
A polysaccharide gives many carbohydrates on
hydrolysis, examples are starch and cellulose.
19. Carbohydrate Structure
Ring (cyclic) form
Pentoses and hexoses are capable of forming ring (cyclic) structures.
An equilibrium exists between the ring and open form.
Linear form
21. Complex Carbohydrates
Cellulose
Most abundant carbohydrate on the planet!
Component of plant cell walls
Indigestible by animals
β 1-4 bonds
Starch
Energy storage molecule in plants
Can be digested by animals
α 1-6 bonds
22. Cellulose
Cellulose is a linear
polysaccharide in which some
1500 glucose rings link together.
It is the chief constituent of cell
walls in plants.
Human digestion cannot break
down cellulose for use as a food,
animals such as cattle and
termites rely on the energy
content of cellulose. They have
protozoa and bacteria with the
necessary enzymes in their
digestive systems. Only animals
capable of breaking down
cellulose are tunicates.
23. Starches
Starches are carbohydrates in which
300 to 1000 glucose units join
together. It is a polysaccharide used
to store energy for later use. Starch
forms in grains with an insoluble
outer layer which remain in the cell
where it is formed until the energy is
needed. Then it can be broken down
into soluble glucose units. Starches
are smaller than cellulose units, and
can be more readily used for energy.
In animals, the equivalent of starch
is glycogen, which can be stored in
the muscles or in the liver for later
use.
α-1,6 bonds
24. Complex Carbohydrates
Glycogen
Branched chain polymer of glucose
Animal energy reserve
Found primarily in liver and muscle
α 1-4 & α 1-6 bonds
26. polysaccharides can be linked to other
molecules to form glyco-proteins and glyco-lipids
27. Glycoproteins
Some examples
Polysaccharide component of antibodies has major effect
on antibody function
Polysaccharides attached to proteins on surface of red
blood cells (RBC) determine blood type (A,B,O)
Polysaccharides are attached to proteins in the Golgi
apparatus through a process of post-translational
modification
Different types of cells do different post-tranlational
modifications
More about this later
28. Glycolipids
Polysaccharides can also be attached to lipid molecules
•An outer-membrane constituent of gram negative bacteria, LPS, which includes O-antigen, a
core polysaccharide and a Lipid A, coats the cell surface and works to exclude large
hydrophobic compounds such as bile salts and antibiotics from invading the cell. O-antigen are
long hydrophilic carbohydrate chains (up to 50 sugars long) that extend out from the outer
membrane while Lipid A (and fatty acids) anchors the LPS to the outer membrane.
30. Lipids
Lipids
Fatty acids (Polymers of CH2 units)
Glycerol
Triglycerides
Other subunits (phosphate, choline, etc) may be attached
to yield “phospholipids”
Charged phosphate groups will create a polar molecule with a
hydrophobic (nonpolar) end and a hydrophillic (polar) end
31. Lipids
Lipids constitute a very diverse group of molecules that all share
the property of being hydrophobic.
Fats and oils are lipids generally associated with energy storage.
Fatty acids, which make up fats and oils, can be saturated or
unsaturated, depending on the absence or presence of double
bonded carbon atoms.
Other types of lipids are used for a other purposes, including
pigmentation (chlorophyll, carotenoids), repelling water (cutin,
suberin, waxes) and signaling (cholesterol and its derivatives).
32. Lipids
Lipids are joined together by
ester linkages.
Triglyceride is composed of 3 fatty acid
and 1 glycerol molecule
Fatty acids attach to Glycerol by covalent
ester bond
Long hydrocarbon chain of each fatty acid
makes the triglyceride molecule nonpolar
and hydrophobic
40. Proteins
Proteins serve many essential roles in the cell
Polymers of amino acids
20 naturally occurring amino acids
A few modified amino acids are used
The large number of amino acids allows huge diversity
in amino acid sequence
N = # of amino acids in a protein
N20
= # of possible combinations
41. Proteins
Proteins consist of one or more polymers called
polypeptides, which are made by linking
amino acids together with peptide linkages.
Peptide linkages are formed through
condensation reactions.
All proteins are made from the same 20 amino acids.
Different amino acids have different chemical
properties.
42. Proteins
Protein’s primary structure largely
determines its secondary, tertiary (and
quaternary) structure.
Proteins subjected to extreme conditions
(large changes in pH, high temperatures,
etc.) often denature.
Proteins act as enzymes, and catalyze very
specific chemical reactions.
43. Protein Function
Some examples
Structure- form structural components of the cell including:
Cytoskeleton / nuclear matrix / tissue matrix
Lamins, collagen, keratin…….
Movement - Coordinate internal and external movement of cells,
organells, tissues, and molecules.
Muscle contraction, chromosome separation, flagella………
Micro-tubueles, actin, myosin
Transport-regulate transport of molecules into and out of the cell / nucleus
/ organelles.
Channels, receptors, dynin, kinesin
Communication-serve as communication molecules between different
organelles, cells, tissues, organs, organisms.
Hormones
44. Protein Function
Some examples
Chemical Catalyst – serves to make possible all of the
chemical reactions that occur within the cell.
Enzymes (thousands of different enzymes)
Defense-recognize self and non-self, able to destroy
foreign entities (bacteria, viruses, tissues).
Antibodies, cellular immune factors
Regulatory-regulates cell proliferation, cell growth, gene
expression, and many other aspects of cell and organism
life cycle.
Checkpoint proteins, cyclins, transcription factors
45. Protein Structure
Polymers of 20 amino acids
All amino acids have a
Common “core”
Amino end (N end)
Acid end (C end, carboxy
end)
Linked by peptide bond
20 different side chains
46. Properties of amino acids
amino acids:
acidic
basic
hydrophobic
Amino acids all have
The same basic structure
Chemical properties of the
amino acids yield
properties of the protein!
48. Protein Structure
The 3-D shape and properties of the protein
determine its function.
Shape and properties of protein determined by
interactions between individual amino acid
components.
Four “levels” of protein structure
Primary (Io
), secondary (IIo
), tertiary (IIIo
), and
quaternary (IVo
) (sometimes).
49. Levels of Protein Structure
I0
(primary) structure
Linear order of amino acids in a protein:
1 A A S X D X S L V E V H X X V F I V P P X I L Q A V V S I A
31 T T R X D D X D S A A A S I P M V P G W V L K Q V X G S Q A
61 G S F L A I V M G G G D L E V I L I X L A G Y Q E S S I X A
91 S R S L A A S M X T T A I P S D L W G N X A X S N A A F S S
121 X E F S S X A G S V P L G F T F X E A G A K E X V I K G Q I
151 T X Q A X A F S L A X L X K L I S A M X N A X F P A G D X X
181 X X V A D I X D S H G I L X X V N Y T D A X I K M G I I F G
211 S G V N A A Y W C D S T X I A D A A D A G X X G G A G X M X
241 V C C X Q D S F R K A F P S L P Q I X Y X X T L N X X S P X
271 A X K T F E K N S X A K N X G Q S L R D V L M X Y K X X G Q
301 X H X X X A X D F X A A N V E N S S Y P A K I Q K L P H F D
331 L R X X X D L F X G D Q G I A X K T X M K X V V R R X L F L
361 I A A Y A F R L V V C X I X A I C Q K K G Y S S G H I A A X
391 G S X R D Y S G F S X N S A T X N X N I Y G W P Q S A X X S
421 K P I X I T P A I D G E G A A X X V I X S I A S S Q X X X A
451 X X S A X X A
Single letter code for amino acids, also a three letter code.
Refer to your genetic code handout.
50. Levels of Protein Structure
Primary Structure
Amino acids combine to form a chain
Each acid is linked by a peptide bond
Io
structure by itself does not provide a lot of
information.
51. Protein Structure
II0
(secondary) structure
Based on local interactions between amino acids
Common repeating structures found in proteins. Two
types: alpha-helix and beta-pleated sheet.
In an alpha-helix the polypeptide main chain makes up
the central structure, and the side chains extend out
and away from the helix.
The CO group of one amino acid (n) is hydrogen
bonded to the NH group of the amino acid four
residues away (n +4).
Can predict regions of secondary structure
57. Nucleic Acid
DNA is transmitted
from generation to
generation with
high fidelity, and
therefore represents
a partial picture of
the history of life.
58. Nucleic Acid
Two types of nucleic acids:
DNA
RNA
DNA stores the genetic information of organisms; RNA is used to transfer that
information into the amino acid sequences of proteins.
DNA and RNA are polymers composed of subunits called nucleotides.
Nucleotides consist of a five-carbon sugar, a phosphate group and a nitrogenous
base.
Five nitrogenous bases found in nucleotides:
the purines
adenine (A)
guanine (G)
the pyrimidines
cytosine (C)
thymine (T) (DNA only)
uracil (U) (RNA only)
59. Nucleic Acids
DNA –deoxyribonucleic acid
Polymer of deoxyribonucleotide triphosphate (dNTP)
4 types of dNTP (ATP, CTP, TTP, GTP)
All made of a base + sugar + triphosphate
RNA –ribonucleic acid
Polymer of ribonucleotide triphosphates (NTP)
4 types of NTP (ATP, CTP, UTP, GTP)
All made of a base + sugar + triphosphate
So what’s the difference?
The sugar (ribose vs. deoxyribose) and one base (UTP vs.
TTP)
60.
61. Function
Nucleic Acids
Information Storage
DNA / mRNA
Information transfer / Recognition
rRNA / tRNA / snRNA
Regulatory
microRNA ?
62. DNA
Information for all proteins stored in DNA
in the form of chromosomes or plasmids.
Chromosomes (both circular and linear)
consist of two strands of DNA wrapped
together in a left handed helix.
The strands of the helix are held together
by hydrogen bonds between the individual
bases. The “outside” of the helix consists of
sugar and phosphate groups, giving the DNA
molecule a negative charge.
66. DNA Structure
1 atgatgagtg gcacaggaaa cgtttcctcg atgctccaca gctatagcgc caacatacag
61 cacaacgatg gctctccgga cttggattta ctagaatcag aattactgga tattgctctg
121 ctcaactctg ggtcctctct gcaagaccct ggtttattga gtctgaacca agagaaaatg
181 ataacagcag gtactactac accaggtaag gaagatgaag gggagctcag ggatgacatc
241 gcatctttgc aaggattgct tgatcgacac gttcaatttg gcagaaagct acctctgagg
301 acgccatacg cgaatccact ggattttatc aacattaacc cgcagtccct tccattgtct
361 ctagaaatta ttgggttgcc gaaggtttct agggtggaaa ctcagatgaa gctgagtttt
421 cggattagaa acgcacatgc aagaaaaaac ttctttattc atctgccctc tgattgtata
Because of the base pairing rules, if we know one
strand we also know what the other strand is.
Convention is to right from 5’ to 3’ with 5’ on the left.
67. Chromosomes and Plasmids
Chromosomes are composed of DNA and
proteins.
Proteins (histone & histone like proteins) serve a
structural role to compact the chromosome.
Chromosomes can be circular, or linear.
Both types contain an antiparallel double helix!
Genes are regions within a chromosome.
Like words within a sentence.
For an animation of the organization of a human chromosome see:
http://www.dnalc.org/ddnalc/resources/chr11a.html
68. RNA
Almost all single stranded (exception is
RNAi).
In some RNA molecules (tRNA) many of the
bases are modified (i.e. psudouridine).
Has capacity for enzymatic function.
One school of thought holds that early
organisms were based on RNA instead of
DNA (RNA world).
69. RNA
Several different “types” which
reflect different functions
mRNA (messenger RNA)
tRNA (transfer RNA)
rRNA (ribosomal RNA)
snRNA (small nuclear RNA)
RNAi (RNA interference)
70. RNA function
mRNA – transfers information from DNA to
ribosome (site where proteins are made)
tRNA – “decodes” genetic code in mRNA, inserts
correct A.A. in response to genetic code.
rRNA-structural component of ribosome
snRNA-involved in processing of mRNA
RNAi-double stranded RNA, may be component of
antiviral defense mechanism.
71. RNA
A - hairpin loop
B- internal loop
C- bulge loop
D- multibranched loop
E- stem
F- pseudoknot
Complex secondary structures can form in linear molecule
72. mRNA
Produced by RNA polymerase as product of transcription
Provides a copy of gene sequence (ORF) for use in
translation (protein synthesis).
Transcriptional regulation is major regulatory point
Processing of RNA transcripts occurs in eukaryotes
Splicing, capping, poly A addition
In prokaryotes coupled transcription and translation can
occur
Editor's Notes
This image shows the primary structure of glycophorin A , a glycoprotein that spans the plasma membrane ("Lipid bilayer") of human red blood cells. Each RBC has some 500,000 copies of the molecule embedded in its plasma membrane. Fifteen carbohydrate chains are "O-linked" to serine (Ser) and threonine (Thr) residues. One carbohydrate chain is "N-linked" to the asparagine (Asn) at position 26. Two polymorphic versions of glycophorin A, which differ only at residues 1 and 5, occur in humans. These give rise to the MN blood groups The M allele encodes Ser at position 1 (Ser-1) and Gly at position 5 (Gly-5) The N allele encodes Leu-1 and Glu-5 Genotype to Phenotype Individuals who inherit two N alleles have blood group N. Individuals who are homozygous for the M allele have blood group M. Heterozygous individuals produce both proteins and have blood group MN . Glycophorin A is the most important attachment site by which the parasite Plasmodium falciparum invades human red blood cells.
Black alpha carbon. Grey carbon, red oxygen, blue nitrogen