Video Review 2:The Electron Transport Chain

This was a video i found while doing CAPE biology. My teacher Mr.Martin (who for dome strange reason have always reminded me of Dr.House) presented this to the class. The basics of this 2 part video has stuck with me since.

Introduction:

The speaker begins by defining what is an electron chain? By the name of it, obviosly is a mechanism by which electrons are transported from one region to another. This statement however is misleading since OVERALLY its not the same electron moving from point A to point B.

• The Electron transport chain (ETC) is made up of protein complexes which are embedded within the mitochondrial membrane, specifically the highly folded inner membrane.
• Electrons are thansferred across it together with H+ pumping
• Pumping of H+ creates a concentration gradient which is utilized by ATP synthase

The complexes which make up the ETC are:

1. NADH Dehydrogenase
2. Cytochrome complex
3. Cytochrome Oxidase
4. ATP Synthase

Yhere are two carries located in the ETC, one located between NADH Dehydrogenase and Cytochrome and another between Cytochrome and Cytochrome Oxidase.

Key substances to the system being:

1. NADH + electrons
2. Hydrogen ions
3. Oxygen molecule
4. Water
5. ADP +Pi -> ATP

The Process:

The mechanism as illustrated by the video beigins where 2 electrons from NADH enter NADH Dehydrogenase, together a Hydrogen ion for EACH electron which goes on to enter the intermembrane space. These 2 electrons are then carried to the second complex by the first carrier, “Ubiquinone” . These electrons are then passed on to the third complex, Cytochrome Oxidase, with 2 more H+ ions being transferred.

Within the Cytochrome Oxidase complex, a mechanism which requires a total of 4 electrons, a molecule of oxygen and eight hydrogen ions, where they react with each other to give H20, and pumping the other 4 hydrogen across the membrane and into the intermembrane space.

In total, 8 Hydrogen ions have been pumped across the membrane. This has created a gradient, the potential energy within it is used by ATP synthase to form ATP, by use of the starting material ADP + Pi. One hydrogeb ion now moves from higher concentration to lower, by passage through ATP synthase as well as another hydrogen ion which moves from the matrix space. This movement of the Hydrogen ions causes a shift in the ATP synthase resulting in the bonding of 1ADP + 1Pi.. 3 H+ ions are required to move from the membrane to form 1ATP molecule, as this is occurring the concentration gradient is gradually decreasing and eventually there will be no more energy to produce ATP. *THIS ONLY HAPPENS IN THE VIDEO, in live systems the gradient is always maintained since there would be complexes performing the reaction simultaneously*

The Good:

• Animations made it interesting to watch
• Processes were explained in a simple manner and was easy to follow
• Video was short! 🙂

The Bad:

• I know of a reaction somewhere in thy chain where Succinate goes to Fumarate
• Failure to mention the basic that the membrane is impermeable to H+ ions
• One must note that the conversion of NADH + H -> NAD+ does occur at the first complex

Lipids video rewiew

Here i am finally doing something OTHER than protein, i think i have an obsession with them or something :S

This here is about lipids, now first things first, lipids are basically fat but…….

 

This is not the type of fat I’m talking about…sure they may be related but….. OMG she’s like just eating the whole bloody cake, like wow..ummm yhhh.

The Basics

Anywho, this video firstly begins with the PenguinProf, who by the way makes some of my favorite educational videos 🙂 , speaking about oils.

Now it is pretty important that she began mentioning oils, why? Duh! Oils are made up of lipids!

• Lipids are important molecules in the body and can provide alot of energy when needed.
• All lipids are hydrophobic
• Are used for long term energy storage
• Are building blocks for membranes, and hormones

The PenguinProf starts off with the mentioning of phospho lipids, which are the components of cell membranes. Their structure is made up of a glycerol backbone, a fatty acid chain, a phosphate group and a variable side group.

The second group she begins to mention is Steroids  The most popular being cholesterol. Keep in mind that cholesterol is ONLY produced in animals so basically when products produced like plants say stuff like “100% cholesterol free” umm, its not like the manufactures took it out in the first place! 😛

Glycerides: A glyceride is an organic molecule which has a glycerol backbone attatched to fatty acid chains. Notice anything?

Isn’t that the description you commonly hear (as a bio/chem student) for fats? well when you are speaking of fats you are actually referring to glycerides, specifically Triglycerides, where the “Tri” comes from the fact that the glycerol backbone ha 3 carbons.

Fats/Glycerides can be of two forms, Saturated and Unsaturated. And I am sure you have at some point in time heard of them and asked what is the difference? What is it saturated or unsaturated with?

To be honest about a year ago I asked the same thing and now that I know the answer, I am so ashamed to say that I have been doing biology and chemistry for like…..5 years! T_T

Do you know what glycerides are saturated or unsaturated with?

Dietary Fats:

The PenguinProf mentions that there are 4 types of fats and indicates where they come from. Those being

1. Saturated: commonly found in animal products (dairy, meats) and may be found in plant oils
2. Mono=unsaturated (1 double bond): nuts, avacadoes
3. Omega-6 polyunsaturated
4. Omega-3 polyunsaturated

For the rest of the video she gives a brief ___ on the naming of Omega-3 and Omega-6 polyunsaturated fatty acids, followed by “Artificial Hrdrogenation” or “Partial Hydrogenation”. Now i found this part really interesting since i often end up reading ingredients etc at the back of my snack or whatever is in my hand (i don’t care if its sad i just like to know whats going inside me -_- ). SHe uses an example showing two triglycerieds, The natural one having three fatty acid chains namely linoleic(x2) and oleic acid. And the second triglyceride having stearic acid, oleic acid and oleic acid.

So……….via hydrogenation with H2 and Nickel catalyst (200-400F)

Linoleic acid -> Stearic acid

Linoleic acid -> oleic acid

Oleic acid -> oleic acid

However she did not mention exactly why it is done 😦

Trans Fats:

Trans fat like unsaturated fats have a C=C bond. But why are they different?

Both hydrogens (1 from each of the carbons) are located on the same vertical direction of the C=C (both are either above or below) where as in trans fat, one H is above whereas the other is below

Why does this make trans fat unique?

FInally she closes with how much fat should be consumed on a regular basis, and to save you the trouble of looking for that…

“No more than 7% of calories (15g) if saturated fat per day and avoid ALL trans fats”

Keep in mind of the serving size! 😀

My review:

Like i said at the beginning, this is one of my favoirite channels on Youtube (i actually have like 10) but I am not turn a blind eye to some faults in her work ofcourse

The Good:

• VIdeo and audio quality is clear, i personally hate background noise from echos of the room to static
• She asks alot of questions, and even though she doesn’t answer a few I feel eager to go and look it up while watching the video
• She is NOT boring 🙂

The Bad:

• A few things she could have gone on to explaining instead of doing it in a separate video
• Some of the questions like “why are trans fats bad” could have been answered
• The information being delivered is basic for any biochemist and should ONLY be used as a quick summary or to give general knowledge to someone who is new to biochem

 

Nucleic acids

Nucleic acids are the chemical compounds that make up out genetic data. It comprises of a 5 carbon ribose sugar backbone, a phosphate group and a nitrogenous base.

Nucleic acids can fall under two categories

• Ribonucleic acids (RNA)
• Deoxyrubonucleic acids (DNA)

Deoxyribonucleic acid as the name suggests is in lack of an -OH group, well the O to be specific.

Ofcouse one must remember that DNA and RNA are large macromolecular structures, the individual monomer which make them up an consist of the 5 carbon sugar, nitrogenous base and the phosphate group is singularly called a nucleotide.

The nitrogenous bases:

There are 5 nitrogenous bases which make up nucleic acids:

• Adenine
• Cytosine
• Guanine
• Thymine
• Uracil

Differences between DNA and RNA:

DNA:

• Stores genetic information
• Exists in a helical structure
• Has a long chain of nucleotides
• Adenine-Thymine & Cytosine-Guanine base pairs
• Is self replicating
• Is generally stable because of existence of more C-H bonds

RNA:

• Transfers genetic information for the synthesis of proteins for which it codes for (production is via ribosomes mRNA & tRNA)
• Exists as a single strand
• A shorter chain of nucleotides
• Adenine-Uracil & Cytosine-Guanine base pairs
• Only synthesized then the production of DNA is needed
• Is generally more reactive die to the presence of more C-OH bonds

The helical structure of DNA is cause by the bonding in between the base pairs along the anti parallel strands of the DNA strands. Bases  Adenine and Guanine are referred to as purines whereas Cytosine and Thymine are referred to as pyrimidines. These base pairs are held together via hydrogen bondsAs you can see, the order in which bases are hydrogen bonded to each other is Pyrimidine to Purine and vice versa. Why doesn’t Thymine bond with Guanine or Cytosine to Adenine? This is because for this bond to be stable and efficient  each of the individual bases must have the same number of substituents which are able to undergo a complete hydrogen bond. The manner by which bonds are always C-G & A-T is referred to as Chargaff’s Rules.

“There is not enough space for two purines to fit within the helix and too much space for two pyrimidines to get close enough together for hydrogen bonds to form between them”

References:

http://www.etap.org/demo/biology_files/lesson5/instruction2tutor.html

Robert’s Syndrome

At the end (or the supposed end) of my last post i had mentioned a little something about Robert’s Syndrome.

Robert’s syndrome is a genetic disorder caused by the interruption of cell division during the embryonic stages of an unborn human foetus. This may cause severe deformity in the limbs, face and possibly the internal organs of the individual.

Affected individuals, aside form physical abnormalities can experience slowed growth before and after birth which tend to further worsen their condition.

Common symptoms:

• shortened arms and legs (hypomelia)
• limbs may be so short that they are located very close to the body (phocomelia)
• abnormal or missing fingers and toes
• joint  deformities along elbows and knees
• cleft lip
• wide set eyes
• small nostrils
• abnormalities in hear, kidneys and genitals

These symptoms may are so drastic that in severe cases infants are either still born or dis shortly after birth 😦

Robert’s syndrome is rare and approximately only 150 individuals have been reported to have it.

Robert’s syndrome is primarily cause by a mutation in the ESCO2 gene. This gene is responsible for proper separation of chromosomes during cell division.

Mutation in this gene results the prevention of the cell producing ESCO 2  protein, which results in sister chromatids to not be “stuck” together around the centromere.

Inheritance background:

Roberts syndrome follows an autosomal recessive pattern (both copies of the gene are mutations of the original gene). It is not sex liked and so both mother and father can have the gene. N.B the parents of an indiviual will have ONE autosomal recessive condition, i.e the parents would be heterozygous for that particular gene and only the dominant form (normal ESCO2 protein prodution) is expressed.

References:

http://ghr.nlm.nih.gov/condition/roberts-syndrome

 

Published paper #2 Centrosome, centrioles and a tiny thing on centromere

If you have ever done anything on the cell before I’m sure you have heard of centrosome, centromere and centriole. Don’t get it twisted they are totally different things, and each time I hear of one my expression is always………

Though its not really my choice of vocabulary…….

But before we get into this review lets diferentiate.

Centiole: A centriole is a cylindrical shaped structure located near the nucleus of the cell and it function lies in the development of spindle fibres which play a major role during cell division. Specifially mitosis and cell division.

Centromere: A centromere is the point on a chromosome which holds two sister chromatides together, it is at this region where spidle fibres attatch and pull the genetic material towards the poles of the cell before cytokinesis occurs.

Centrosome:  Its main function is in the organisation of microtubules in animal cells. Which means that this structure is the reason why spidle fibres assort in a specific way for cell division. But not only does it regulate this assortment but it also plays key role in cell motility, signalling, protein trafficking/regulation(via the microtubule cytoskeleton) and signalling. I know that some of these sound similar to that of the centriole but I hope this diagram helps to clear things up.

How centrosomes perform their organizing structure:

MIcrotubules are structers formed by the polymerisation of “Tubulin”. And their active behaviour regulated by proteins. In the cell specific structures have these protiens and as such have the ability to independently control these microtubules. Within the cetrosome lies the cylindrical structures  centrioles  which are in turn surrounded by these proteins, referred to as pericentriolar material (PCM). Regulation proteins (NOT those referred to as PCM) by the centromere rely on the intrinsic polarity of the microtubules and motor proteins associated with them. Controlling the movement of these microtubules thus gives the centromere the ability to rgulate proteins and other substances across it, since it acts like a track along which they will pass. Regulation of this also gives speed of transport at variable quantities, based on the cells requirements.

Centrioles are unlike any other micreobubule assiociated organelle in the cell. It is composed of 0 triplets of stable microtubules aloocated in the well known cylindrical arrangement portrayed way at the very beginning. Centrioles can be mounted on the menbrane of a cell, at which point is it now referred to as”basal bodies” Thes basal bodies produce the stater material known as axoneme which gives rise to  the rigidity and mobility of cillia and flagella. within the centromere there are usually two types of centrioles.

• Mother centriole (older) : microtubules and distal appendages are docked here, i.e this is the point at which it is connected to the cell membrane
• Daughter centriole:

Microtubules produced by centriaoles are highly stable and are resistant to cold temperatue (which usually causes  microtubules to constrict) and are also resistant to alkiline pH changes

Petricentriolar Material:

Somewhere earlier I have mentioned that the PCM is involved in the controlling of microtubules. PCM determines the overall size of the centromere as well as its overall capability and efficiency and is composed of many different proteins, in humans being

• BBS4, Bardet-Biedl syndrome 4 protein
  
• Lck, Proto-oncogene tyrosine-protein kinase LCK
• PCM1, Pericentriolar material 1 protein
• TNKS, Tankyrase-1
• TNKS2, Tankyrase-2
• TUBE1, Tubulin epsilon chain

Importance:

It must be noted that centrosomes are not important in ALL organisms, for example somatic cells and Drosophila (common fruit fly) as well as man other animal cells (red blood cells etc) have no requirement for such a structure. However most animal cells do have a microtubule cytoskeleton.

• The microtubule cytoskeleton provides structural support and shape for the cell and allow for regulation of substances across it (these do not necessarily need to be formed via the centrosome)

Centrosomes are important in cell division and protein regulation and so if there is a malfunction in the centrosome or the centriole, a variety of issues can arise.

Abnormalities in the centriole duplication for instance is likely to be the origin of genome instability which is typically observed in cancer cells.  Centromere abnormality can occur from ear;y stages of human development and it is expected that if there is a fault in the centomere, there is a high probability that  fault would also occur in the PCM and the centioles themselves. Faults in either of these can cause

• Incomplete separation of cells during cytokinesis (can lead to a tumour)
• Incomplete separation of chromosomes
• improper regulation of proteins
• in terms of being a basal body can lead to abnormal development in cillia and flagella
• may totally disrupt reproduction of cells
• Roberts syndrome : a rare genetic disorder caused my the disruption of cell division

References:

http://www.ncbi.nlm.nih.gov/pubmed/22729084

http://www.biomedcentral.com/1741-7007/11/28

Published Paper 1

This is my first published paper review (its gonna need some updating)  and I have to admit, I had no idea of the complexity of enzymes and …my head hurts now so I shall not be going in depth to this article. Ofcourse you are free to read it on your own.

Have you ever heard of a Kinase Inhibitor Disease? I haven’t!

Firstly what is a kinase?

• A kinase is an enzyme which “modifies” a molecule by means of transfer of a phosphate from an ATP molecule to the molecule which takes part in the catalysed reaction.

According to the abstact of the article, Kinases have important roles when it comes to signalling pathways and cell regulation….. So what does this mean for humans, kinases….kinase inhibitirs….cell regulation?

I’m not sure what you are thinking but I do believe if you have a kinase inhibitor, you are basically not going to have proper metabolic mechanisms and therefore you are pretty much dying slowly 😦

Ok that may have been a little harsh.

The article goes on to mention that diseases (cancers, neurological and metabolic) often characterize the ability to deregulate kinase functions and it is expected that these may be a particular target when dealing with drugs. Meaning inhibitors are good…when using them AGAINST the diseases. However problems arise:

• They are large in numbers
• The lack selectivity/ specificity
• They tend to unintentionally interact with multiple protein kinases
• They are unbiased and so would react with the kinases which belong to the body (these are what cause side effects from drugs)

Yi-Yuan Chiu and associates have created a database on a mass number of kinases and inhibitors in order to find which would have been useful. This database is referred to as KIDFamMap.

KIdFamMap is the first database to explore the relationship between kinase-inhibitor-families (KIF’s) andKinase-inhibitor-disease (KID) with reference to the selectivity between enzyme and inhibitor.

SOME OUTSIDE INFO:

“A protein kinase inhibitor is one in which specifally blocks activity of one or more protein kinases.” Most of the kinases known today act on both serine and thysorine. I.e. they have a dual specificity. Kinases cause the phosphorylation of their complementary amino acids and since they can also react with histidine, a kinase may possess the ability to alter, interfere or even repair DNA. The fact that a kinase can affect DNA makes its inhibitor useful in the treatment of cancer.

Here is a list of drugs I found which target kinase inhibitors:

Name	Target	Company	Class	FDA Approval
Bevacizumab	VEGF	Genentech	Monoclonalantibody	2004 Colorectal
BIBW 2992	EGFR/Erb2	Boehringer Ingelheim	Small molecule	Not yet
Cetuximab	Erb1	Imclone/BMS	Monoclonal antibody	2006 Mar (SCCHN)
Imatinib	Bcr-Abl	Novartis	Small molecule	2001 (CML)
Trastuzumab	Erb2	Genentech/Roche	Monoclonal antibody	1998
Gefitinib	EGFR	AstraZeneca	Small molecule	2003
Ranibizumab	VEGF	Genentech	Monoclonal antibody	2006 (AMD)
Pegaptanib	VEGF	OSI/Pfizer	RNA Aptamer	2004 (AMD)

References:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3531076/

http://www.news-medical.net/health/Kinase-Inhibitor-What-is-a-Kinase-Inhibitor.aspx

Hair………and stuff

So what day it was, I was watching the Tube with my mom and all of a sudden, ‘le commercial cosmétique’ comes up  and while the models are showing off how shiny and bouncy their hair is, although I was completely zoned out, I managed to hair (get it, hear…hair?) something about Collagen and Vitamin E. So I asked myself a question, what makes hair shiny? As a matter of fact, we live in a world where both men and women have many different hair types.

Well? I’m a guy, my hair looks nothing like this and I know nothing of hair at all, so I got nothing! But from the last blog, I mentioned that both Keratin and Collagen may be found in hair. Hmmm, that can’t be it, that’s just 2 compounds which can give so many hair types. Without taking genetics and its genotype-phenotype relationship into consideration (since environment changes the later anyway), I managed to find that the following can contribute to hair textures and types.

• Collagen
• Keratin
• Vitamin A
• Vitamin B (complex)
• Vitamin E
• Folic acid

As we know not, collagen and keratin are structural compounds found in many parts of the body. Coupled with is ability of high tensile strength, it would be common sense to make the assumption that the more you have, the stronger your hair is.

Ashraf Khamis, a stylist at Butterfly in Maadi explains that hair is exposed to harsh conditions, chemicals, heat and styling on a regular basis, this damages the outer layer of the hair known as the Follicle. As many women will know, damaged hair equals split ends which are a BIG “no-no!” Breakage in hair follicle can result in abnormal growth rate. Sadly research done on other factors of hair which collagen contributes to are sketchy at best. It is said that treating hair with collagen is an exterior application. Temporary effects which reduces frizz, gives softness, and a smoother touch. Unlike its counterpart Keratin, collagen does not have that straightening ability (expected due to its helical structure).

What makes hair curly?

Personally, in that picture above i see absolutely no difference between curly and kinky hair, if there is a significant difference please let me know.

“Naturally curly” says that curly hair occurs due to the amount of disulphide bonds between hair proteins. Sulphur containing proteins specifically being Methionine and Cysteine. So on a nut shell, the more sulphide linkages the curly the hair! Well that was quickly answered, why do i feel like I’m missing something?

What makes hair straight?

Well this is simply the opposite  Since more disulphide linkages make hair curlier, less disulphide linkages means………. that’s right straighter hair 😛
But here’s some thing extra. Ever noticed that after u take a shower your hair is a lot curlier compared to how it was during the day? Yes? No? Maybe?

Now we remember that proteins can interlink with each other by use of hydrogen bonds. Keratin, a major component of hair does the same thing.These hydrogen bonds between keratin molecules are weak of-course but can be enhanced by the presence of water. This slightly contradicts with what i said earlier about keratin having a straightening ability, but keep in mind that i did say that the hydrogen bonds are weak, the slightest exposure to heat and environmental characteristics would make these minor hydrogen bonds in keratin disappear!

We can take it a little further with respect to hair products. Why do some of them have the caption “Tame your Curls”? How do these chemicals completely remove curly from one’s hair? These shampoos, relaxers and conditioners simply coat your hair with oils which prevent the absorption of water. How? Ever tried mixing oil and water? It’s almost impossible, you simply get two distinct layers. This is because the water is polar and oil is non polar. Hair products utilities these characteristics of these compounds, coating hair with a non polar substance which negates all possibility of moisture entering (and leaving) hair strands and interfering with these hydrogen bonds. Keep in mind that water has no effect on disulphide bonds in curly hair, and by removing these bonds a more permanent situation arises  (i.e it does not naturally go back to its original state)!

What makes hair SHINY?

Firstly one must understand exactly what IS shiny.According to Dictionary.com shiny is the ability to reflect light due to being clean, reflective and polished.

That cant be it? I bathe often, shampoo often, wear grease occasionally, and NEVER has my hair have the slightest glisten of white. The problem with this definition is that it only applies to smooth surfaces. You may ask “isn’t hair smooth?” well……..I hope that answers that question (btw i HATE seeing microscopic images like this, makes me wanna puke! ).

Anyway, assuming that out hair is healthy you can see that it is far from being “smooth”. Again what makes hair shiny……….. well I got nothing on this. Every search i did resulted in “Ladies..how to make your hair shine 🙂 “, so my educated “guess” would be that hair is not naturally shiny, to the extent where it looks like the ones in the first picture.

With the introduction of hair products and a large number of oils present in one’s scalp (whether self secreted or otherwise) fills the microscopic ridges of the individual strands allowing for a temporary smooth texture of a seemingly transparent coating or “cuticle”. This cuticle in turn would have natural light refraction and reflecting characteristics (like cooking oil on your skin) and collectively with it’s host and all other strands it appears shiny o.O

………..or something like that

OH and here’s a remedy, so if there’s any girl brave enough to try this tell me how it goes http://www.wikihow.com/Have-Soft-Shiny-Hair-Inexpensively

 

References:

http://www.egyptindependent.com/news/salons-prescribe-collagen-treatment-unhealthy-hair

http://www.naturallycurly.com/curlreading/retexturizing/keratin/what-makes-curly-hair-curly

http://www.ccmr.cornell.edu/education/ask/?quid=708

https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcR2uACkhVlboxYVwvwHuhXSpHmLvvz76BKmQamOUehA_6UVe3yuWg

Glycolysis questions

To be honest i actually came up with some of these questions while doing biochem during my chem lecture, it a bad habit but oh well now i know where my preference is. So here are my very simple questions 🙂
Btw, #10 is actually a question that I’m unsure about since i have read that it is, but in the glycolytic pathway diagram, no ATP is seen entering/leaving

1)      Which of the options contain ALL of the enzymes which catalyse the irreversible reactions of glycolysis?

a. Phosphoglucose isomerase, aldolase, pyruvate kinase

b. Hexokinase,phosphoglycerate kinase, enolase

c. Phosphofructo kinase, Phosphoglycerate mutase, Pyruvate Kinase

d. Hexokinase, Phosphofructo kinase, Pyruvate Kinase

2)      Why is the conversion of NAD+ -> NADH + H important?

a. To remove excess H ions from the system as it leads to acidity increase in cells

b. Picks up electrons removed from glycolysis and its NADH form makes up the electron transport chain

c. It acts as a reducing agent in the conversion of Glyceraldehyde-3-Phosphate to n1-3 Bisphosphoglycerate

d. None of the above

3)      Which of the following steps does not take place in the 10 steps of glycolysis?

a. NAD⁺ + 2H → NADH + H⁺

b. ADP  + Pi → ATP

c. ATP → ADP

d. Dihydroxyacetonephosphate ↔ GLyceraldehyde-3-phosphate

4)      Why are the three irreversible reactions…….IRREVERSIBLE?

a. The ∆G value for the reactions are too high

b. The ∆G value for the reactions are too low

c. Products which are formed from the reactions are too unstable

d. Reactants disrupt the glycolitic pathway if kept in their initial state for long periods

5)      What is the process by which ATP is formed?

a. Condensation

b. Phosphorylation

c. Oxidation

d. None of the above

6)      Which is the process by which NADH is formed?

a. Oxidation

b. Reduction

c. Condensation

d. All of the above

7)      Enzymes for Glycolysis are located in the mitochondria of all cells.

a. True

b. False

8)      Any 6-Carbon sugar can enter the glycolytic pathway?

a. True

b. False

9)      The Kinase enzymes in glycolysis involves the use of ATP to add a phosphate group to the substrate and can also remove a phosphate group from such a substrate.

a. True

b. False

10)      The step which involves the enzyme Glyceraldehyde-3-Dehydrogenase can be reffered to as a major energy generating step.

a. True

b. False

Biochem quiz

1) Which of the following is the structure for D-Glucose?

 

Questions 2- 5 relates to the following. Glucose in nature exists in the various structures

a)      D- glucose

b)      L- glucose

c)       Alpha (α) -glucose

d)      Beta (β) – glucose

2) Which of these is the straight chained structure which is most abundant in nature?
3) Which is the starting unit for the structure of starch?
4) Which of these is mainly found in cellulose?

5) Which subunit which makes up the illustrated structure?

 

6)  Which of the following is TRUE about the differences between prokaryotic and eukaryotic cells?

a)Eukaryotic cells have vesicles where as Prokaryotic cells do not

b) Both have DNA wrapping on proteins

c) Vacuoles are present in plant eukaryotic cells and in prokaryotic cells which can undergo photosynthesis

d) The cell wall present in eukaryotic cells is much simpler than the cell wall found in prokaryotic cells

7) Motile Cilia and Flagella are structures present on cells and one of their functions is for mobility of the cells. Which of the following is FALSE?

a)Cilia are short structures(compared to flagella) , and there may be many hundreds per cell
b)Flagella moves in a wave like, undulating, sinusoidal movement, propelling the cell forward
c)Cilia is present on eukaryotic cells
d)Flagella may be found both on prokaryotic and eukaryotic cells

8)      For each step in Glycolysis, there is a different enzyme present. Which of the following enzymes is said to be the most “regulating”?

a) Hexokinase
b) Phosphofructokinase
c) Phosphoglucose isomerise
d) Fructose-bisphosphate aldolase

9)      In glycolysis, from the movement from 1 glucose molecule to two pyruvate molecules, a series of molecules is produced or used up. Which of the following is FALSE?

a) At the end of glycolysis there are 4 ATP molecules
b) 2 molecules of NADH are produced
c) 2 molecules of NAD+ are produced
d) The NET change in ATP molecules is +2 ATP

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I am so not pleased with this…needs more words 😦