Molecular B2 Flashcards
Transcription
Carbs
Replication
Ucc stuff
UCC
Proteins are composed of amino acids. How many amino acids are there?
How are different proteins made?
How are proteins made?
How does RNA polymerase know where to start from?
20 amino acids
Different proteins are made by combining these 20 amino acids in different combinations
Step 1- transcription
Part of DNa temporarily unzips and is used as a template to assemble complementary nucleotides into messenger RNA(mRNa)
Nucleotides are added into a complimentary strand of mRNa based on the DNA code
This mRNa strand leaves the nucleus and goes to the ribosome for translation
Translation steps:
mRNaa is read by rRNA
rRNa makes up the ribosome
mRNa is read three bases at a time
Every three bases on mRNa codes for one amino acid and is called a codon
A codon refers to three bases on mRNa that codes for one amino acid
Amino acids are brought until the entire mRNa is read.
Each tRNA drops off one amino acid then goes into the cytoplasm to grab another
The Ribosome bonds each amino acid together using a peptide bond creating a polypeptide
Eventually the stop codon is reached and the final amino acid is added
It knows because mRNa has a start codon which is a specific three letter nucleotide sequence that says begin here
The start codon on mRNA is the three letters AUG
Remember how big DNA is
The entire molecule is not used to make mRNa just a small portion
Stop codon tells RNA polymerase to stop making the protein
UCC
What is cellular reproduction specifically binary fission and give examples of organisms that reproduce by binary fission
Give types of binary fission
From 1 cell to 2 cells
Example Amoeba,bacteria,euglena,paramecium
So I’m binary fission the DNA undergoes replication and then cytokinesis into two identical daughter cells
Binary fission is a type of asexual reproduction
The prokaryotic chromosome duplicates or replicates
There is continued cell growth
Cells divide into two identical daughter cells
Prokaryotes have cell wall
Longitudinal binary fission:divides the cells into left and right
Transverse binary fission :divide into up and down
Irregular binary fission
UCC
Explain the cell cycle
A cell cycle is thus a sequence of events that a cell goes through as it grows and divides to produce new cells. Therefore, it can be called the life cycle of a cell.
True or false
Chromosome is made up of DNA which is made up of a gene true or false
A single chromosome has a chromatid and a centromere
A duplicated chromosome has sister chromatids and a centromere true or false
What’s a homologous chromosome
What is an allele?
What is meiosis
What’s the difference between meiosis I and meiosis II
Explain how meiosis occurs
Explain the role of growth factors in cell cycle
Gnot or G subscript 0 is the phase where there is cell cycle arrest
G1 the cellular contents excluding the chromosomes are duplicated or there hs cell growth
S phase each of the 46 chromosomes is dubplicated by the cell or there is DNA replication
G2 phase the cell “double checks” the duplicated chromosomes for error making any needed repairs or there’s progressive mitosis
All true
A homologous chromosome are chromosomes that all have the same genes in the same places along their length
An allele is different forms of chromosome on the same gene
Meiosis takes place only in the reproductive cell types (sperm and egg cells) of sexually reproducing organisms, including humans. For a cell to undergo meiosis, it must have a diploid (2n) chromosome number.
In meiosis I, a pair of homologous chromosomes separate to produce two diploid daughter cells, each having half the number of chromosomes as the parent cell. In contrast, during meiosis II, sister chromatids separate to produce four haploid daughter cells. Also, unlike meiosis I, no genetic recombination by crossing over occurs in meiosis II.
Interphase :
Cell replicates it’s chromosomeS
Each chromosome has two sister chromatids held together by a centromere
Prophase 1:
Chromosome could up and a spindle forms
Homologous chromosomes come together to form a tetrad
Crossing over May occur resulting in variations
Metaphase 1:
Centromere of each chromosome becomes attached to a spindle fiber
Spindle fibers pull the tetrads to the equator of the spindle
Homologous chromosomes line up side by side as tetrads
Anaphase 1:
Homologous chromosomes separate and move to opposite ends of the cell
Centromeres do not split
This ensures that each new cell will receive only one chromosome from each homologous pair
Telophase 1:
Spindle breaks down and chromosomes uncoil
Cytoplasm divides to yield two new cells
Each cell has half the genetic information of the original cell because it has only one homologous chromosome
Prophase II:
A spindle forms in each of the two new cells and fibers attach to the chromosomes
Metaphase II:
The chromosomes line up randomly at the equator
Anaphase II:
The centromere of each chromosome splits
The sister chromatids separate and move to opposite poles
Telophase II
Nuclei are formed
Spindles break down
The cytoplasm divides (cytokinesis)
Meiosis II is identical to mitosis
Growth factors such as serum are hugely specific proteins required in very low concentrations for effective running of the cell cycle
It is known that cultured cells deprived of serum stop proliferating and arrest in Gnot or G0
Ucc
Explain how mitosis occurs in the cell cycle
What checkpoints are there in the cell cycle
Ucc
What are labile cells,stable cells,permanent cells
What is quiescence
A eukaryotic cell cycle consists of two main parts: 1) interphase and 2) mitotic (M) phase, and an alternative part called the G0-phase.
1) Interphase
It is the first phase of the cell cycle, recognized by the growth period where the chromosome gets duplicated as the cell prepares for division. Interphase happens between one cell division or mitotic (M) phase and the next. It is the longest part of the cell cycle involving three sub-phases. The typical duration of this phase is 23 hours.
G1-phase: Also known as the first-gap phase, during this period, the cells grow in size, synthesize cell organelles and other macromolecules such as proteins that serve as the building block of the cell. The cells also accumulate sufficient energy required for division.
S-phase: Also known as the synthesis phase, the existing DNA is copied within the nucleus. This process of DNA synthesis is also known as DNA-replication. The centrosome is also duplicated during this phase and gives rise to spindle fibers. The entire S-phase requires energy expenditure to proceed.
G2-phase: This is the second gap phase and is somewhat similar to the G1-phase. During this period, the cells grow further in size, making more proteins and organelles. All preparations for mitosis get completed before the cells enter the mitotic phase.
2) Mitotic (M) Phase
This period is also known as the cell division phase and occurs just after the G2-phase. Here, the cell divides its genetic material (DNA) and cytoplasm to form two new cells. The M-phase involves two different critical processes that unfold in the following order:
a) Mitosis or Karyokinesis
It is the nuclear division period and consists of four phases: prophase, metaphase, anaphase, and telophase. During this phase, the cell divides the nucleus and gets separated into two daughter cells, where each daughter cell receives a complete set of chromosomes. The details of its different phases are discussed in the mitosis article.
b) Cytokinesis
It is the process by which the cytoplasm of the cell splits to form two independent cells. The phase of cytokinesis begins towards the end of mitosis such that the two processes overlap. Cytokinesis is the shortest phase of the cell cycle that occurs differently in plants and animals.
The division in plant cells occurs by forming a cell plate structure in the middle of the cell. The cell plate is made of components made of the cell membrane and cell wall.
The division in animal cells happens when a band of cytoskeletal fibers known as contractile rings forms just below the cell membrane in the metaphase plate’s position. The contractile rings contract inwards, thus creating a depression or crack, called cleavage furrow. The cracks increase, and slowly the membrane cleaves to form two daughter cells at the end of the cell cycle.
End Result
Two individual daughter cells are formed, each having identical copies of the genetic material.
G0-phase
Some cells do not immediately enter another round of preparatory phase or interphase following the division or mitosis. Instead, they exit the G1 growth phase and enter a resting stage called G0-phase. Thus, G0 is also called the alternative phase of the cell cycle. Some cells enter the G0-phase temporarily until an outside signal triggers the onset of G1. In contrast, other cells that either never divide or seldom divide, such as nerve cells or cardiac cells, remain in G0-phase permanently.
The main checkpoints are:
- G1-checkpoint: Present just before the entry into S-phase, it makes the critical decision whether the cell will enter the S-phase. The decision is based on whether the cell is big enough and has synthesized proteins necessary for DNA synthesis.
- G2-checkpoint: Checks errors in the DNA-synthesis phase and, based on the result, bars the entry into the M-phase. This checkpoint helps to prevent the occurrence of cancer in higher animals. Suppose there is an error in DNA replication. In that case, the G2 checkpoint prevents the cell from progressing further in the cell cycle and checks the error in the newly formed DNA.
- M-checkpoint: This occurs near the end of the metaphase stage. It checks whether all sister chromatids are correctly attached to the spindle fibers. The M-checkpoint ensures that equal division of chromosome occurs between the two daughter cells.
In cellular biology, labile cells are cells that continuously multiply and divide throughout life. This continual division of labile cells allows them to reproduce new stem cells and replace functional cells that are lost in the body
Example hematopoietic stem cells
Labile cells multiply continuously, and are found in bone marrow, various tissues, skin, and in the linings of most hollow organs in the body. Stable cells only multiply when needed or if another cell is destroyed or damaged, and are found in the liver and many other glands.
In cellular biology, stable cells are cells that multiply only when needed. They spend most of the time in the quiescent G0 phase of the cell cycle but can be stimulated to enter the cell cycle when needed. Examples include the liver, the proximal tubules of the kidney and endocrine glands.
3) the permanent cells, incapable of multiplication in the adult—only the permanent cells are incapable of regeneration. These are the brain cells and the cells of the skeletal and heart muscles.
Quiescence is the reversible state of a cell in which it does not divide but retains the ability to re-enter cell proliferation. Some adult stem cells are maintained in a quiescent state and can be rapidly activated when stimulated, for example by injury to the tissue in which they reside
Ucc What are Carbohydrates State the classification of carbs How are monosaccharides classified ? What are enantiomers State the differences between D and L sugars
They contain element sCHo and the chem structure is C6H12O6
Monosaccharides:cannot be hydrolysis further into smaller units
Disaccharides
Polysaccharides
Carbs usually end with the suffix -Ose
Example gluc-Ose,malt-Ose,cellul-Ose
Monosaccharides are classified based on the number of carbon atoms
Number of carbon atoms:3
Type of monosaccharides is triose
4-tetrose
5-pentose
6-hexose
They are also classified according to the type of carbonyl group they contain
Example:aldehyde=Aldose:aldohexose
Ketone=ketose:ketohexose
There are two simple classes of the carbonyl group: Aldehydes and Ketones. Aldehydes have the carbon atom of the carbonyl group is bound to a hydrogen and ketones have the carbon atom of the carbonyl group is bound to two other carbons.1
Those monosaccharides that contain an aldehyde functional group are called aldoses; those containing a ketone functional group on the second carbon atom are ketoses.
To understand better,look at the structure of glucose and fructose and see the difference
Use this link https://chem.libretexts.org/Courses/Sacramento_City_College/SCC%3A_Chem_309_-General_Organic_and_Biochemistry(Bennett)/Text/14%3A_Carbohydrates/14.2%3A_Classes_of_Monosaccharides
Thus, monosaccharides are described as aldotetroses, aldopentoses, ketopentoses, ketoheptoses, and so forth. Glucose and fructose are specific examples of an aldohexose and a ketohexose, respectively
So monosaccharides can only be classified as either aldoses or ketoses then you add the number of carbons
Molecules that are nonsuperimposable (nonidentical) mirror images of each other are a type of stereoisomer called enantiomers (Greek enantios, meaning “opposite”).
a) D- and L-glyceraldehyde are mirror images of each other and represent a pair of enantiomers
Sugars whose Fischer projections terminate in the same configuration as D-glyceraldehyde are designated as D sugars; those derived from L-glyceraldehyde are designated as L sugars. The main difference between D and L Glucose is that D-Glucose rotates plane polarized light clockwise whereas L-Glucose rotates plane polarized light anticlockwise. The main difference between L and D isomers is that the OH- group of the penultimate carbon is positioned on the right side of the D isomer whereas, in L isomer, it is located on the left side. D-Glucose is the enantiomer of L-Glucose, for example.
D sugars-dextrorotatory
L-levorotatory
Look at pictures of l and d sugars
UCc:
What is stereogenecity or stereogenic/chiral Centre
Give examples of Naturally occuring D sugars
Look at pictures of stereogenic centers in the examples of naturally occuring D sugars
The ability of a C atom to exhibit enantiomerism
An atom, or a grouping of atoms, is considered to be a stereogenic center if the interchange of two ligands attached to it can produce a new stereoisomer. All chiral centers are stereogenic centers but all stereogenic centers are not chiral centers.23 Jun 2017
Stereo center is a point in a molecule which can give rise to stereoisomers. Chiral center is a carbon atom to which four different atoms or groups of atoms are bonded. Nature. A stereocenter is a point in a molecule, not necessarily an atom. A chiral center is a carbon atom.
D -fructose
D-glucose
D-ribose
D-glyceraldehyde
Ucc:
Explain ring formation and mutarotation: alpha and beta forms
Give examples
Mutarotation is the change in the optical rotation because of the change in the equilibrium between two anomers, when the corresponding stereocenters interconvert. Cyclic sugars show mutarotation as α and β anomeric forms interconvert.
When β-D-glucopyranose is dissolved in water, it rotates a plane-polarized light by +18.7°. Some amount of β-D-glucopyranose undergoes mutarotation, to give α-D-glucopyranose and it turns a plane-polarized light by +112.2°.
The mutation occurs when the anomeric position (C1) changes its configuration between α and β form in the solution. As a result, carbohydrates undergo ring-opening to form hemiketal (aldehyde form) and reforms into a hemiacetal (closed ring).
The mutation occurs when the anomeric position (C1) changes its configuration between α and β form in the solution. As a result, carbohydrates undergo ring-opening to form hemiketal (aldehyde form) and reforms into a hemiacetal (closed ring).
Alpha is better for humans and beta is better for animals (ruminants)
Ucc:
What are disaccharides
Explain anomerism or acetal or hemiacetal formation in disaccharide
Why is it that reducing sugars can be metabolized in humans, but non-reducing sugars cannot?
Difference between acetal / hemiacetal formation or anomerism
Explain pyrans and furans and give examples
Difference between alpha anomers and beta anomers with regards to cis and trans
Two monosaccharides: glucose + glucose = maltose
Glucose + fructose= sucrose
Glucose + galactose = lactose
C-1 of glucose become chrial carbon and has two possible arrangements of H and OH group around itThese two arrangements of glucose which differ only in the orientation of hydroxyl group at C-1 are called anomers. Eg:- α-D-Glucose and β-D-Glucose.
We can conclude that the Sucrose is not a reducing sugar because it does not have a hydroxyl group in the ring. Hence, sucrose does not show mutarotation. All other disaccharides are reducing sugars
Because reducing sugars can open their cyclic structure into the straight chain form, whereas non-reducing sugars cannot
Explanation:
When it comes to metabolizing sugars, only reducing sugars are able to undergo breakdown. This is because reducing sugars are able to be converted from their closed chain form into their open chain form. It is only in the open chain form that sugars such as glucose can be metabolized.
Only reducing sugars can be converted into their open chain form. The reason for this is that the anomeric carbon for these sugars is not occupied
Anomers are cyclic monosaccharides or glycosides that are epimers, differing from each other in the configuration of C-1 if they are aldoses or in the configuration at C-2 if they are ketoses. The epimeric carbon in anomers are known as anomeric carbon or anomeric center.
Example 1: α-D-Glucopyranose and β-D-glucopyranose are anomers.
Hemiacetal is formed as an intermediate product between acetal formation. Hemiacetal and acetal are acknowledged as functional groups. The critical difference between hemiacetal and acetal is that hemiacetal contains one -OH and one -OR group while acetal contains two -OR groups.
Acetal: Acetal is a group of atoms that is represented by a central carbon atom bonded to two –OR groups, -R group and a –H group. Hemiacetal: Hemiacetal is a group of atoms composed of a central carbon atom bonded to four groups; an –OR group, -OH group, -R group and a –H group.
Where R is the carbon group
furanose compounds have a chemical structure that includes a five-membered ring system containing four carbon atoms and one oxygen atom whereas pyranose compounds have a chemical structure that includes a six-membered ring structure consisting of five carbon atoms and one oxygen atom.
Aqueous glucose-pyranose
Aqueous fructose- furanose
the research group of Walter Haworth, who conclusively determined that the hexose sugars preferentially form a pyranose, or six-membered, ring. Haworth drew the ring as a flat hexagon with groups above and below the plane of the ring – the Haworth projection.
When an open chain monosaccharides cyclizes to a furanose or pyramids form,a new stereogenic center is formed at what used to be the carbonyl carbon.
The two stereomers produced are called Anomers and the hemi-acetal carbon atom is called an anomerism Centre
Alpha-anomer (α-anomer): A carbohydrate in which the group bonded to the anomeric carbon is trans to the CH2O group on the other side of the pyranose or furanose ring ether oxygen atom. In α-D-glucopyranose the anomeric OH is trans to the CH2OH. In β-D-glucopyranose the anomeric OH is cis to the CH2OH.
The key difference between alpha and beta anomers is that in alpha anomer, the hydroxyl group at the anomeric carbon is cis to the exocyclic oxygen at the anomeric centre, whereas in beta anomer, the hydroxyl group is trans to the exocyclic oxygen.
Ucc:
What’s the structural importance of polysaccharides
What do Aldoses react with tk yield oxidized sugars?
Why are Aldoses reducing sugars?
Cell walls
Chitin : a fibrous substance consisting of polysaccharides, which is the major constituent in the exoskeleton of arthropods and the cell walls of fungi.
Lignin : a complex organic polymer deposited in the cell walls of many plants, making them rigid and woody.
Polysaccharides are complex sugars example amylase,cellulase,starch
Aldoses react with Tollen’s,Fehling’s,Benedict’s reagents to yield oxidized sugars
They are reducing sugars because the sugar reduces the oxidizing agent
Some diabetic test kits use Benedict’s test that gives a reddish precipitate as a positive sign
Other oxidizing agents include the earth metals example formic acid,oxalic acid and sulphite compounds
Ucc:
What is an epimer,a carbonyl group,furanose,pyranose,glycoprotein,glycoside formation,acetal,
What are the two kinds of starch,what’s the major difference between amylose and amylopectin,what’s the basic chemical difference between starch and cellulose,what’s the chemical nature that makes it impossible for humans to digest cellulose,what’s the biological nature of humans that makes it impossible to digest cellulose,what is cellobiose,partial hydrolysis of cellulose?
What are glycosides,homoglycans,heteroglycans,epimerism,enolization,oxazone,proteiglycan,Pataus syndrome,klinefelters syndrome
Epimer:one of a pair of stereoisomers that differ in configuration at only one stereogenic Centre
Carbonyl group: a carbon atom with a. Double bond to oxygen and a single bond to hydrogen atoms or alkyl group
Furanose: five members cyclic hemiacetal structure
Pyranose: six membered rings
Glycoprotein:
Carbohydrate with a protein part (conjugated protein)
Glycoside formation: reaction of monosaccharides with alcohol with and acid catalyst. They form glycosidic linkages
Acetal: a functional group consisting of two ether type oxygen atoms bound to the same carbon
Types of starch:
Starch consists of glucose molecules. It can occur in two forms: amylose and amylopectin. Amylose is a linear or straight-line polymer that scientists describe as amorphous or solid. Amylopectin forms a branched chain and is crystalline. Or The main difference between amylose and amylopectin is that amylose is a straight chain polymer whereas amylopectin is a branched chain polymer
Amylopectin is more in starch than amylose and is more soluble in water than amylose and it forms a gel wben hot water is added and the amylose doesn’t do that
Starch and cellulose: There is only one difference. In starch, all the glucose repeat units are oriented in the same direction. But in cellulose, each succesive glucose unit is rotated 180 degrees around the axis of the polymer backbone chain, relative to the last repeat unit. Starch contains alpha glucose, while cellulose is made of beta glucose
The presence of beta acetal linkages in cellulose makes it different from starch and is a deciding factor in its digestibility. Humans lack the enzyme required to break down the linkages.
Humans can digest starch but not cellulose because humans have enzymes that can hydrolyze the alpha-glycosidic linkages of starch but not the beta-glycosidic linkages of cellulose.
The reason is due to the different types of bonding between cellulose and starch. Cellulose has beta-1,4 bonds that are not digested by our enzymes (which can digest alfa-1,4 and alfa-1,6 bonds that are present in starch and glycogen).
The key difference between cellobiose and cellulose is that cellobiose is a disaccharide, whereas cellulose is s polysaccharide. Moreover, cellobiose is a reducing sugar while cellulose is a non-reducing sugar.
Definition of cellobiose
a faintly sweet disaccharide C12H22O11 obtained by partial hydrolysis of cellulose.
Glycosides are naturally occurring substances composed of a sugar that is linked to another functional group via a glycosidic bond. They are colorless, amorphous, solid, non-volatile compounds. They give a positive test with Molisch and Fehling’s solution test. They have solubility in water but are insoluble in organic solvents.
The glycosidic bond joining these two components is usually through an oxygen (O), sulfur (S) or a nitrogen atom (N).
Homoglycan: A polysaccharide is called a homoglycan when it contains only one type of monosaccharide unit, for example, cellulose,glycogen are all composed of glucose subunits .A large number of plant products belong to this particular category, namely, honey, starch,
Heteroglycan: A polysaccharide is known as a heteroglycan when it involves more than one kind of monosaccharide unit, for example, d-gluco-d-mannose is made up of d-glucose and d-mannose.
Epimers are carbohydrates which vary in one position for the placement of the -OH group. The best examples are for D-glucose and D-galactose
Epimerization is a process in stereochemistry in which there is a change in the configuration of only one chiral center. As a result, a diastereomer is formed. The classical example of this in medicine is tetracycline.
Enolization or a keto-enol-tautomerism is a process of converting a ketone kr an aldehyde to a corresponding enol (in acidic conditions) or an enolate (in basic conditions)
An enol is an organic compound that contains a hydroxyl group bonded to a carbon atom having a double bond and that is usually characterized by the grouping C=C(OH)
Osazone test is a chemical test used to detect reducing sugars. This test even allows the differentiation of different reducing sugars on the basis of the time of appearance of the complex. This test is also termed Phenyl hydrazine test based on the reagent used for this test.
Osazones are a class of carbohydrate derivatives found in organic chemistry formed when reducing sugars are reacted with excess of phenylhydrazine at boiling temperatures
glycoprotein: any of a class of proteins which have carbohydrate groups attached to the polypeptide chain. lycoproteins are proteins which contain oligosaccharide chains covalently attached to amino acid side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. Example of glycoproteins are antibodies
There are three types of glycoproteins based on their structure and the mechanism of synthesis: N-linked glycoproteins, O-linked glycoproteins, and nonenzymatic glycosylated glycoproteins. Glycoproteins are always found on the outside of the plasma membrane, with the sugar facing out.
Proteoglycans are glycosylated proteins which have covalently attached highly anionic glycosaminoglycans.
in proteoglycans, one or more glycosaminoglycan chains are attached to the protein while in glycoproteins, oligosaccharide chains are attached to proteins. The largest in size and most abundant by weight is aggrecan, a proteoglycan
Patau syndrome: A condition in which a person has an extra chromosome 13.
Patau syndrome is the result of trisomy 13, meaning each cell in the body has three copies of chromosome 13 instead of the usual two. The most common cause is nondisjunction of chromosome 13 during meiosis.
Klinefelter syndrome
Also called: XXY syndrome
A genetic condition in which a male is born with an extra copy of the X chromosome
Due to maternal nondisjunction cases are caused by meiosis I errors,
Ucc:
Explain the history of cells
Explain the cell theory
Cells must’ve able to divide,they vary in size and shape,some cells are organisms onto themsekves(unicellular example bacteria) and they’re the simplest form of life. Others only fu croon when they ar w part of a large organisms (multicellular) such as cells making up the human body true or false
The nucleus and cytoplasm is made up of?
Give some examples of membranous organelles and define them
Give some examples of non membranous organelles and define them
Is the cell wall membrane bound or non membrane bound
What are the characteristic of the nucleus
State the types of cells and state the charac of prokaryotic cells and eukaryotic cells
In the 17 th century 1670,Robert Hooke upon examining cork with a microscope observed that it was made of tiny chambers.
With his knowledge of small rooms or chambers found in monasteries at that time called in Latin Cella,he names these chambers cells
Similar compartments were seen in animal tissue
In 1838,Schleiden and Schwann: hypothesized that all plant and animal tissues were made up of cells
Robert Remak and Rudolf Virchow: how are living things reproduced?
All organisms are composed of one or more cells
The cell is the basic building block of all organisms
Cells arise form pre existing cells
Cells were then deemed the ultimate units of living organisms because cells are the smallest potential Independent unit of a living organism
Later,cells were found to contain smaller structures such as nucleus in their cytoplasm
Nuclear envelope
Chromatin
Nucleolus
Cytoplasm:
Inclusions(non living cytoplasmic materials . Structures not usually surrounded by a plasma membrane example lipids,glycogen,pigment granules) and organelles(little organs. A specialized sub unit within a cell that has a specific function. Types of organelles include membranous or membrane limited compartments and non membranous example microtubules
Membranous organelles:
Plasma(cell) membrane:
A lipid bilayer that forms the cell boundary and boundaries of many organelles in the cell
Rough surfaced endoplasmic reticulum:
Associated with ribosomes and site of protein synthesis and modification of newly synthesized proteins
Smooth surfaced endoplasmic reticulum:
Involves in lipid and steroid synthesis
Golgi apparatus:
Has multiple flattened cisternae for modifying,sorting and packaging proteins and lipids for intracellular or extracellular transport
Endosomes:
Sorting proteins delivers to them via endocytotic vessels and redirecting them to different cellular compartments for their final destination
Lysosomes:
Contain digestive enzymes,digest invaders,breakdown of old cell parts.
Mitochondria:
Provision of most energy to the cell by producing adenosine triphosphate (ATP) in the process of oxidative phosphorylation
Peroxisomes: degradation of molecules like fatty acids,amino acids and foreign substances
Non membranous organelles:
Microtubules- form part of the cytoskeleton and continuously elongate( by adding Tubulin dimers ) and shorten
Ribosomes: responsible for protein synthesis and composed of ribosomal RNA
Filaments: form part of the cytoskeleton and are of actin filaments and intermediate filaments
The organelles that are non-membranous include ribosomes, the cytoskeleton, the cell wall, centrosomes, and the centrioles. These organelles are not contained by a membrane, unlike membrane-bound organelles.
The nucleus is the most prominent organelle in the eukaryotic cell
It’s a double membrane structure and contains the genetic information of the cell and contains the chromosomes and nucleolus(direct synthesis of RNA and forms ribosomes)
Prokaryotes: capsule,cell wall,plasma membrane,cytoplasm,ribosomes,plasmid,pill
Prokaryotes don’t have a nucleus,are spherical,rod like shaped and small,presence of cell wall,simple and limited in structure,have circular or linear DNA,has nucleoid that is a region of DNa concentration and is lived mostly as a single celled organism but some join to form chains or clusters or other organized multicellular structures example bacteria,archaea
Spiral shape: treponema pallidum,
Rod shaped: escherichia coli
Spherical:streptococcus
Eukaryotes: possess nucleus,have organelles and other sub cellular structures
Bigger and more elaborate ,some live as independent and singe celled organisms such as amoebae and yeast
Example yeast,fungus,protozoan,plant and animal
What are the types of biological molecules
Name the four types of non covalent or weak interactions among bio molecules in aqueous solvent
Weak interactions are crucial to macromolecular structure & function true or false
Types of biological molecules
– Proteins (all synthesized from the same 20 species of amino acids)
– Nucleic acids (made from 8 types of nucleotides) – Polysaccharides (made from 8 commonly
occurring types of sugars)
– Lipids (made up of alcohols and fatty acids)
Hydrogen bonds between neutral groups and between peptide bonds
Ionic interactions:attraction and repulsion
Hydrophobic interactions
Van der Waals
What is the formula for pH?
Name four acidic and neutral and basic examples
Why is pH important and what happens if it alters?
Weak Acids are the acids that do not completely dissociate into their constituent ions when dissolved in solutions.
What’s the pH of trypsin
What the relationship between acid,Ka and pKa
State the Henderson-Hasselbalch equation
What’s the use of this equation
When will pH be equal to pKa
pH+pOH=14
pOH= -log[OHraised to the power -]
Acidic:lemon juice,gastric juice,black coffee,milk,saliva,beer,tomato juice,vinegar,red wine
Basic:seawater,egg white,household bleach and household ammonia,solution of baking soda
What happens if it alters?
E.g. Blood pH constant at ~7.4
– If pH <7.3 CO2 not removed from cells—– acidosis
– In severe diabetes, pH can fall to 6.8 coma and death
Intracellular pH ~7.4
– Enzymes and metabolic processes sensitive to pH
– How is pH maintained? Neutral solution pH is 7
Not an arbitrary number Derived from ionic product of water
Neutral:human blood and tears (pH of 7 is neutral)
Trypsin:around 6,
Pepsin: around 2
Weak acids and bases have characteristic dissociation constants:
CH3COOH can dissociate to form CH3COO- + H+
HA can dissociate to form A- + H+
Keq = [A-] [H+] divided by [HA] = Ka(dissociation constant)
K_a = acid dissociation constant [A^-] = concentration of the conjugate base of the acid [H+] = concentration of hydrogen ions [HA] = concentration of chemical species HA
pKa= -logKa = log
1 divided by Ka
Stronger the acid ,Higher the Ka ,Lower the pKa
pH=pKa + log [A raised to the power -] / [HA]
The Henderson-Hasselbach equation is used to
• Calculate pKa, given pH and molar ratio of proton donor and acceptor
• Calculate pH, given pKa and molar ratio of proton donor and acceptor
• Calculate the molar ratio of proton donor and acceptor, given pH and pKa
pH= pKa+ log
[proton acceptor] / [proton donor]
When [proton acceptor] = [proton donor], pH= pKa
When [A]=[HA] or at the midpoint of titration then pH=pKa
Explain buffers
Buffers work from 1 pH unit below to 1 pH unit above. So if the pKa is 4.76, the buffering region will be between 5.76-3.76
their pKa true kr false
Buffers
• Buffers are solutions that resist changes in pH as acid and base are added
• Most buffers consist of a weak acid and its conjugate base
• Note in titration figure how the plot of pH versus base added is flat near the pKa
• Buffers can only be used reliably within a pH unit of their pKa
How many sugars do the chains of the types of carbohydrates contain
State the functions of carbs
State the types of carbs
Monosaccharides under organic chemistry can be classified into what and what?
Monosaccharide (1)
Oligosaccharide (2-20)
Polysaccharide (>20)
Main role of “carbo” (Carbohydrates) in nature Storage of energy Structural support Lipid and protein modification recognition by IgG /cell cell communication
Carbohydrates are hydrates of carbon Chemical composition (C . H2O)n n>3 • Monosaccharides (simple sugars) • Oligo = "a few" - usually 2 to 10 • Polysaccharides are polymers of the simple sugars
Types
Carbohydrates
• Monosaccharides (simple sugars)
• Disaccharides
• Oligosaccharides(short-chain carbohydrates)
• Polysaccharides (long chain carbohydrates)
Monsaccharides
An organic chemistry review
• Aldoses and ketoses contain aldehyde and ketone functions, respectively
• Triose, tetrose, etc. denotes number of carbons
• Aldoses with 3C or more and ketoses with 4C or more are chiral
polyhydroxy: Aldehydes Ketones are aldoses are
ketoses
Number of carbons:
3=triose 4=tetrose 5=pentose 6=hexose
What’s re the types of monosaccharides with regards tk the number of carbons and with regards to polyhydroxyl
Look at examples of stereoisomers of glyceraldehyde and how they differ r
Triose - Smallest monosaccharide
Has three carbon atoms Tetrose (4C)
Pentose (5C) Hexose (6C) Heptose (7C) etc…
Name :triose -Formula- C3 H6 O3 tetrose -formula-C4 H8 O4 pentose-formula-C5 H1 0 O5 hexose-C6 H1 2 O6 heptose -C7 H1 4 O7 octose-C8 H1 6 O8
Aldoses (e.g., glucose) have an aldehyde group at one end
Ketoses (e.g., fructose) have a keto group, usually at C2
Aldehydes and Ketones. Both aldehydes and ketones contain a carbonyl group, a functional group with a carbon-oxygen double bond.
Propanal is an example of an aldehyde functional group. R−CHO is a general structural formula for Aldehyde.
What are enantiomers
What does D mean in D aldoses
What are epimers and give example
Cyclic form of glucose and fructose is called?
Read about what ucc talked about concerning carbs
Mirror image configurations(read UCc definition)
D-aldoses
D refers to configuration at chiral center most distance
from carbonyl carbon
Two Sugars that only differ in configuration around one carbon atom
Cyclic monsaccharide structures and anomeric forms
• Glucose (an aldose) can cyclize to form a cyclic hemiacetal
• Fructose (a ketose) can cyclize to form a cyclic hemiketal
• Cyclic form of glucose is a pyranose • Cyclic form of fructose is a furanose
Cyclization leads to pair of diasteromers known as anomers
• Hemiacetal or the hemiketal C is known as
• For D-sugars, alpha has OH down, beta up
What are reducing sugars
Why do ketoses act as reducing sugars
Sugars on mild reaction produce what?
Monosaccharide Derivatives
• Reducing sugars: sugars with free anomeric carbons - they will reduce oxidizing agents, such as peroxide, ferricyanide and some metals (Cu and Ag)
• These redox reactions convert the sugar to a sugar acid
• Glucose is a reducing sugar - so these reactions are the basis for diagnostic tests for blood sugar
Sugars as reducing agents
(Ketoses isomerize to aldoses under the conditions used for these oxidation reactions with copper ions and thus also act
as reducing sugars.)
Produce sugar alcohol
Example sorbitol,mannitol and xylitol
Used to sweeten sugarless food products
Name three important monosaccharides and why they’re important
What are disaccharide
Give examples
What links two monosaccharides?
Important monosaccharides
• Glucose - Aldose. Preferred source of energy for brain cells and cells without mitochondria
• Fructose – ketose. Sperm use this as major sugar/energy source for motility
• Galactose - important for lactose (milk sugar) production
Disaccharide - two monosaccharides linked together
Linked via a glycosidic linkage
• Examples:
– Sucrose (table sugar) : • Glucose + fructose
– Maltose:
• Glucose + Glucose
– Lactose (milk sugar) : • Glucose + Galactose
This ring can’t open up and is no longer reducing This ring can open up to an aldehyde and is still reducing
Sugars bearing anomeric C that has not formed glycosidic bonds are called reducing sugars
Because they reduce mild oxidizing agents
Why can’t people hydrolyze lactose ?
Take note of this: Oligosaccharides and other carbs
Don’t memorize structures, but know the important features
• Be able to identify anomeric carbons and reducing and nonreducing ends
• Sucrose is NOT a reducing sugar
• Note carefully the nomenclature of links! Be able to recognize alpha(1,4), beta(1,4), etc
Hydrolysis of dietary Lactose
• Some people don’t produce enough lactase, the enzyme that hydrolyzes lactose, and so can’t digest lactose
• Many adults become lactose intolerant
What are polysaccharides
State functions
What’s their nomenclature
Polysaccharides
(also known as glycans)
Functions: storage, structure, recognition
• Nomenclature: homopolysaccharide vs. heteropolysaccharide(look at the difference on the slides)
• Starch and glycogen are storage molecules
• Chitin and cellulose are structural molecules
• Cell surface polysaccharides are recognition molecules
What are structural polysaccharides
What’s the model of cellulose
Structural Polysaccharides
Composition similar to storage polysaccharides, but small structural
differences greatly influence properties
• Cellulose is the most abundant natural polymer on earth
• Primary structural component of plant cell walls
• Cellulose can also be soft and fuzzy - in cotton
• Linear polymer of up to 15,000 D-glucose residues
Model of Cellulose
Highly cohesive, H-bonded structures give cellulose
fibers exceptional strength & make them water
insoluble despite their hydrophilicity
Wood and bark are insoluble formed from cellulose
