PSL 250 Exam 1 AQs

Can you explain how a plasma membrane, solely constituted of phospholipids, is inherently semipermeable?

The plasma membrane is inherently semipermeable due to its hydrophobic interior and hydrophilic surfaces (i.e., P and E faces). The plasma membrane is permeable to small, non-polar substances and gases, but is impermeable to polar/charged molecules/ions.

Can you explain the process by which cholesterol enters your body cells?

Cholesterol enters into cells via receptor-mediated endocytosis. During this process the LDL receptors in the cell membrane will recognize and bind LDL. The plasma membrane will invaginate forming a vesicle that contains the LDL molecules. Cholesterol will then be released into the cytosol of the cells from the LDL molecules.

In terms of the concentration of hydrogen ions in solution, what is the difference between a pH of 7.0 and a pH of 4.0?

1000x... 3 fold difference

During high intensity exercise, you can easily lose 1 liter of water per hour of exercise. Let's say a man lost 5 liters of water during one workout. How many cups of water would he have to drink to replace this volume of water lost?

20 cups... 4 cups in a liter

What is the stoichiometry (i.e., numbers and direction of ions transported) of the Na+/K+ pump? Can you provide a detailed explanation of secondary-active transport?

3 Na+ out, 2 K+ in... Secondary transport occurs due to a chemical gradient that is generated by primary active transport. One example of this is the entrance of glucose into the small intestine. The entrance of glucose into intestinal cells is coupled with the entrance of Na+ ions into the cells. SGLTs are the transporters. So, the concentration gradient of Na+ (created by the actions of the Na+/K+ pump - a primary active transporter) drags glucose into the cell. Since the SGLT does not directly use the energy of ATP, but rather the gradient of Na+ created by Na+/K+ pump, it is considered to be a secondary-active transporter.

If you eat a meal that contains 40 g glucose, 16 g protein, and 15 g fat, how many total calories?

359 kcal

How is it that all cells of your body (except gametes) have the same DNA yet there are approximately 200 different types of cells?

Differential gene expression. In other words, a cheek cell has the same genes as a liver cell, but the two cells are very different from one another. They are different because each cell has a different set of genes turned on/off.

What is a mesentery? What are its functions?

A mesentery refers to the double layer of visceral peritoneum... the peritoneum surrounds organs of the gut. The mesentery is the suspension of two layers of visceral peritoneum coming together before enveloping the organ. It contains blood vessels that carry nutrients from the organ to the body

What are two things that are required for anything to cross the plasma membrane?

A pathway and an energy source

What is Pitocin and how does it work?

A pharmaceutical version of oxytocin that is administered through an intravenous drip and stimulates the contraction of the uterine muscles when labor must be induced.

What is the difference between a primary lysosome and a secondary lysosome?

A primary lysosome is a vesicular organelle formed by the golgi. It contains acid hydrolase but they are not functional as the pH is too high. A secondary lysosome is formed by the fusion of a lysosome and an endosome or phagosome. A secondary lysosome has a pH of 5 (which is the ph that acid hydrolase functions optimally at)

What literally are ABO blood group antigens? How does A differ from B, AB and O?

ABO blood antigens are sugars that are attached to proteins (make up the glycocalyx)

What are the three components of the cytoskeleton? What are the subunits that comprise each? Which cytoskeletal filaments support microvilli? Cilia? Which are responsible for mediating pseudopodial movement?

Actin filaments (G actin OR F actin-- not both... two subunits form one dimer), intermediate filaments, microtubules Actin supports microvilli. Microtubules support cilia Actin is responsible for pseudopodial movement

What is the difference between active and passive transport? What is the difference between simple diffusion and facilitated diffusion?

Active transport utilizes the energy of ATP. Passive transport utilizes the energy of a concentration gradient. In simple diffusion molecules cross the membrane on their own (i.e., the plasma membrane itself is the pathway). In facilitated diffusion, molecules require a transport protein to assist their movement across the bilayer (i.e., the transport protein is the pathway). In both circumstances, a concentration gradient is required as the energy source.

With an understanding of the central dogma of life, can you explain how elucidating the sequence of the protein insulin allowed scientists to ultimately clone the human insulin gene?

After discovering the protein sequence for insulin, scientists were able to encode the RNA that was complementary to the protein sequence. From there they could find out which amino acids made up the polypeptide chain (protein)

What two functional groups do all amino acids have? What makes one amino acid structurally unique from another? What are the two functional groups that interact between two individual amino acids to form a dipeptide. What is the specific name of the bond that links two amino acids together?

Amino groups and carboxyl groups. R groups make them unique. Amino group and carboxyl group interact to form peptide bond (covalent)

What is the difference between a resting membrane potential (RMP) and a transmembrane potential (TMP)? What is the primary mechanism responsible for a RMP?

An RMP is the transmembrane potential at which the cell is at rest. K+ leaks channels are primarily responsible for establishing a RMP.

What is the difference between an integral membrane protein and a peripheral membrane protein? How does a carrier protein differ from a channel protein?

An integral membrane is embedded in the membrane, whereas a peripheral membrane protein is loosely associated with the membrane (they are either on the P or E side, but do not go through the membrane to both sides). A carrier protein binds to a particle, changing conformation so that the particle can be carried across the membrane into the cell. A channel protein is a pore on the membrane that opens and closes to allow solutes through.

What is cellulose? Why can't humans digest it? Does it contain calories?

Cellulose is the structural support molecule in plants. It is a linear polymer of glucose monomers that makes up the plant cell wall. It contains calories, however humans do not have the capacity to extract its calories. Humans cannot digest it because they do not produce cellulase. Cows have a rumen stomach containing bacteria that cuts up cellulose. They can swallow grass into their rumen stomach, ferment it with bacteria, regurgitate the clump, and then swallow it into their normal stomach to extract calories.

What is the primary mechanism by which water crosses the lipid bilayer? What are a few good examples of molecules that freely can pass the lipid bilayer?

Aquaporins. Lipids and gases. In general, small, hydrophobic molecules.

Why are virtually all cells of the human body within 20 µm of a capillary?

Because diffusion is distance limited.

Can you explain how a phospholipid is structurally similar to a triglyceride? Phospholipids are amphipathic molecules. What does amphipathic mean and what unique properties do amphipathic molecules have? How does a micelle differ from a lipid bilayer membrane?

Both phospholipids and triglycerides consist of fatty acids attached to glycerol. Triglycerides have 3 fatty acid tails, while phospholipids only have 2. Amphipathic means there are polar and nonpolar region (semipermeable). Micelles are a single layer of lipids, whereas the membrane is a double layer

Can you write out the bicarbonate buffer equation? What is the name of the enzyme that catalyzes this reaction? If a patient has a blood pH of 7.0, what medical condition do they have? Will their respiratory rate increase or decrease to try to correct for this condition? What might their kidneys do?

CO2 + H2O ←-> H2CO3 ←-> HCO3- + H+ Carbon dioxide + water ←-> carbonic acid ←-> bicarbonate ion + hydrogen ion Catalyzed by carbonic anhydrase Blood pH lower than 7.4 is acidosis Respiratory rate will increase and kidneys will excrete H+ ions.

Can you explain how ATP is the link between catabolic and anabolic reactions in the human body?

Catabolism is the breaking down of a molecule, accompanied by the release of energy. Anabolism is the formation of a complex molecule from simpler molecules, utilizing energy. When food is consumed, our bodies first begin to break the food down into simpler molecules. By breaking the food down, energy is released. This energy is used to add phosphate to ADP, forming ATP. ATP is then hydrolyzed; when the bonds are broken, energy is released that can be used to convert the simple molecules into complex macromolecules that our bodies need (such as carbs, fats, proteins)

How does cholesterol in the membrane affect membrane fluidity? If cholesterol is so important in maintaining the integrity of membranes, why is it often seen as bad for you?

Cholesterol maintains the integrity of the membrane. When the environment is too warm, the phospholipids tend to spread apart. When the environment is too cold, they pack together tightly. Cholesterol prevents these changes from becoming too drastic. Cholesterol is often seen as bad because it is mistaken for LDL. Low density lipoproteins are responsible for carrying cholesterol to the cells that need it, however high levels of LDLs can lead to arterial plaque buildup.

Can you explain how distance, size of solute, steepness of gradient, temperature and electrical forces can influence the rate of diffusion?

Concentration gradient gets weaker with increasing distance. Larger solutes diffuse slower than smaller solutes. The steeper the gradient, the faster the rate of diffusion. Higher temperature increases the rate of diffusion. Electrical forces influence the rate of diffusion if the diffusing solute is polar or charged. For example, if Na+ is diffusing into the cell, it has both a chemical gradient (more Na+ on the outside of the cell than the inside and an electrical gradient (the inside of the cell is negative and Na+ is positive).

What are the two components of the cytoplasm? What is the difference between intracellular fluid and extracellular fluid? What is the difference between extracellular fluid and interstitial fluid?

Cytosol and organelles Intracellular fluid is inside the cell. Extracellular fluid is outside of the cell... includes interstitial fluid and intravascular fluid Extracellular fluid is interstitial fluid + plasm

What are the three germ layers of an embryo and which of the four principal tissue types do each give rise to?

Ectoderm → external lining of the body (i.e., the skin) and the nervous system. Mesoderm → muscle tissue, connective tissue and the inside lining of blood vessels (endothelium). Endoderm → internal linings of the body.

What is glycogen? Where is it stored in humans? What molecule is glycogen structurally and functionally similar to in plants?

Glycogen is the polysaccharide that is the major energy store in humans. It is stored in the liver and skeletal muscle. It is highly branched so it is structurally similar to amylopectin (starch)

HDL and LDL are often erroneously referred to as "good" and "bad" cholesterol, respectively. What does a physician actually mean when they say that HDL is "good cholesterol"?

HDL and LDL are carrier micelles that transport cholesterol. LDL is considered bad cholesterol because it carries cholesterol to tissue and can cause arterial plaque buildup. HDLs are considered good cholesterol because it carries cholesterol to the liver to be destroyed. Cholesterol itself is not bad, but too much can be associated with cardiovascular disease.

A cell is hypertonic to its environment. Will the cell crenate or swell? Which has a lower osmotic potential, the cytosol of the cell or the interstitial fluid?

If a cell is hypertonic to its environment, the cell will swell up, and potentially lyse. The cytosol of the cell has lower osmotic potential (i.e., more dissolved solute).

If a patient is hypertensive, a physician may prescribe a low-salt diet. Can you explain how this would be a potentially effective mechanism for lowering a persons' blood pressure?

If a patient is hypertensive, their blood pressure is too high. By consuming less salt, there will be less salt in the bloodstream. This means that the environment outside of the vessels will have a higher solute concentration by comparison, so water will diffuse out of the blood vessels to dilute the extracellular environment. This lowers the volume of fluid in the blood vessels, and therefore lowers blood pressure.

What is/are the effector(s) in the positive feedback regulation loop of parturition? What is the afferent information? How is efferent information transmitted to the effector(s)?

In parturition, the effectors are the uterine smooth muscle cells. Nerve impulses that the head of the baby is pushing against the cervix are sent as nerve impulses to the brain (afferent). The brain stimulates the pituitary glands to secrete oxytocin (efferent). Oxytocin is carried to the uterus through the blood stream and stimulates uterine contractions so that the head of the baby is pushed further into the cervix.

is a lipid a type of fat or a fat a type of lipid

fat is a type of lipid. all fats are lipids, but not all lipids are fats (steroids, phospholipids, etc.)

One human cell can synthesize a fully functional insulin molecule? With recombinant DNA technology, why are two bacterial cells required to make a fully functional human insulin molecule?

Insulin is a quaternary protein, meaning it consists of two subunits (an alpha chain and a beta chain)... this requires two bacterial cells because each makes one subunit. Bacterial cell cannot perform post translational modifications, so the subunits must be brought together in a test tube

Is insulin hydrophobic or hydrophilic? Is cholesterol hydrophobic or hydrophilic? If either of these are hydrophobic, how are they transported in the bloodstream?

Insulin is hydrophilic. Cholesterol is hydrophobic, which is why it is carried in LDL's and HDL's (amphipathic molecules)

Why is insulin such an important protein, historically and physiologically?

Insulin was the first protein to ever be sequenced and the first human recombinant protein

How are intermediate filaments involved in cell-cell attachment?

Integral membrane proteins that bind and communicate with one another are tethered to intermediate filaments that wrap around the cell

Can you explain how the high specific heat of water relates to body temperature regulation via vasodilation and vasoconstriction?

It takes a lot of energy to increase or decrease water temp by just one degree.... This means water can carry a lot of energy, but not be very hot itself (if our blood was too hot, proteins would be denatured). During vasodilation, blood vessels swell so that blood circulation increases and heat can be released through the skin. During vasoconstriction, blood vessels constrict so that warmth stays near the internal organs.

What are the 3 different ways in which channels are gated in the human body?

Ligand gated: open in response to a specific ligand binding to the receptor Voltage gated: open as a result in the electrical membrane potential Mechanical gated: open and close in response to mechanical pressure or vibration (such as sound waves)

What is the general name of the enzyme that degrades triglycerides? What is the name of the type of reaction this enzyme catalyzes? What is the specific name of the bond that this enzyme cleaves?

Lipase degrades triglycerides... breaks ester bonds through hydrolysis

What are the two main types of microtubule-associated proteins (MAPs)? If a cell makes a protein near the nuclear membrane and needs to transport this protein towards the plasma membrane, which of these two MAPs would mediate this transport?

MAPs are proteins that hydrolyze ATP in order to move along the microtubule and transport material throughout the cell. Kinesin (plus/anterograde... from nucleus to plasma membrane) and dyenin (negative/retrograde... from plasma membrane to nucleus)

Cigarette smoking can decrease the motility of cilia in the respiratory tract. What complications could this cause?

Mucus cannot be cleared away and ends up plugging the respiratory tract. This leads to restriction of airflow and respiratory infections.

All naturally occurring elements are electrically neutral. Therefore, sodium (Na) and chloride (Cl) are elements with no charge. So, how is it that these two elements electrostatically combine to form the ionic compound NaCl?

Na only has one electron in its valence shell, and Cl has seven, so its electronegativity is much higher. Because of this, Na donates an electron to Cl, becoming more positive (a cation). Cl gains the electron so it becomes more negative (anion). This is an ionic bond.

What is the most abundant extracellular cation? Intracellular cation? Is Cl- more abundant intracellularly or extracellularly? What are the anions inside the cell?

Na+. K+. Extracellularly. Negatively charged cytosolic proteins, DNA and RNA.

What cells that you are born with essentially never divide again throughout life? How can you prove this?

Neurons, muscle cells and fat cells. Places you would never get cancer, such as your heart, biceps, etc.

Are gap junctions part of a junctional complex? What is their function?

No, gap junctions are pores that let ions and small molecules move between cells. They are often referred to as communicating junctions.

When NaCl dissolves in water, hydration spheres form around Na+ and Cl- ions. Do the water molecules of the hydration spheres surrounding Na+ have the same orientation as the water molecules of the hydration spheres surrounding Cl-? Why or why not?

No. Water is an amphipathic molecule, meaning it has polar and nonpolar regions. The negative oxygen is attracted to the positive sodium, while the positive hydrogens are attracted to the negative chloride

What are the four levels of protein structure? What type of bonds holds together the secondary level? At which level do proteins first gain functionality? Hemoglobin has what level of protein structure? How about insulin?

Primary: linear chain of amino acids held together by peptide bonds Secondary: alpha helix or beta pleated sheet held together by hydrogen bonds Tertiary: 3D shape due to interactions between R groups... first gain functionality Quaternary: protein consisting of several tertiary subunits... hemoglobin and insulin are both examples of quaternary proteins

In terms of quantity, 98% of a plasma membrane is lipid (most of which are phospholipids) and 2% is protein. However, 50% of the weight of a plasma membrane is lipid and 50% is protein. What does this latter fact say about proteins in the membrane?

The proteins are much larger and denser than the phospholipids

Organelles are not listed as one of the levels of organization of life. Can you put forth a logical argument for why they are not part of the hierarchy of life?

Organelles are the tiny functional units that are within some cells, however not all cells contain organelles. Also organelles do not make up cells entirely

What's the name of the cell that can increase blood calcium levels? What's the name of the cell in which the entire bicarbonate buffer system works inside its cytoplasm? What's the name of the cell that contains a brush border? What's the name of the cell that makes connective tissue in your body?

Osteoclast. Red blood cell (RBC). Enterocyte. Fibroblast.

Bacterial cells living on and in your body outnumber your own cells? If bacteria are so bad, why are they "part of" us?

Our bacterial flora prevent disease causing bacteria from colonizing our bodies.

Peroxisomes produce antioxidants? Where are the oxidants generated that these antioxidants combat? Why are oxidants (or free radicals) so dangerous to the human body? What is a good example of a vital function of free radicals in the body?

Oxidants (free radicals) are generated by reactions such as cellular respiration (i.e., the oxidation of fuels). Oxidants are dangerous because they can steal electrons from molecules that make up the cells and tissues of your body. Ultimately, bonds are broken, and cells and tissues are damaged leading to disease. Free radicals (such as superoxide anion or hydroxyl radical) can be used in the body by phagocytes to destroy pathogens. Free radicals (such as nitric oxide) vasodilate blood vessels which helps maintain proper blood flow.

The human body is approximately 60% water. So, if there are two hydrogen atoms for every one oxygen atom in a single molecule of water, why does oxygen make up a greater percentage of total body weight than hydrogen?

Oxygen is much heavier than hydrogen

Is phosphocreatine made while you are exercising or during rest? Creatine phosphokinase (CPK) is a kinase? What does a kinase do in general? When CPK coverts phosphocreatine to creatine, what molecule gets phosphorylated?

Phosphocreatine is made during rest and broken when energy is depleted. Kinases add phosphates to molecules ADP is phosphorylated when the phosphate is removed from phosphocreatine

Phospholipids are the primary active ingredients in laundry detergent. How do phospholipids work to remove dirt and grime from clothes?

Phospholipids are amphipathic, so when they are placed in water, they form micelles. The hydrophobic tails interact with the grime and trap it so that the micelle forms around the dirt. When these little bubbles leave the washing machine they carry the dirt with them.

What does it mean that a cell is polarized? Depolarized? Can you explain a few ways in which a cell could become depolarized? Hyperpolarized?

Polarized cells are more negative on the inside than on the outside. Cells become depolarized when ions such as Na+ or Ca2+ flow into the cell and make the cell less negative on the inside, and therefore less polarized. Cells become hyperpolarized when ions such Cl- enter the cell or when K+ leaves the cell.

Are ribosomes membranous or non-membranous organelles? What is the difference between fixed and free ribosomes? What are the structural and functional differences between smooth and rough endoplasmic reticulum?

Ribosomes are non membranous. Fixed are attached to the ER, free are in the cytosol. The RER consists of sacs with ribosomes attached to them. Its function is to synthesize proteins that become membrane proteins or leave the cell. The SER is an organized collection of spherical sacs that functions in lipid biosynthesis, protein transport, drug detoxification, and calcium storage.

How do saturated fatty acids differ from unsaturated fatty acids? Is a trans-fat a saturated fat? What is the chemical process that is utilized to convert unsaturated fats into saturated fats? Why would someone want to do this?

Saturated fatty acids have as many hydrogens attached to each carbon as possible, meaning they can stack together in tight chains. Unsaturated fatty acids contain at least one double bond, meaning there is less hydrogen and there are kinks in the structure. Trans fats are not saturated fats because they still contain double bonds and are kinked. Converting unsaturated fats to saturated fats occurs through hydrogenation (makes solid at room temperature)

What is a brush border? Where would you expect to see a brush border in the body? What is a brush border enzyme?

Short, immotile, cytoplasmic projections of microvilli on the surface of a cell that increase its surface area. Located in places where absorption occurs (i.e. small intestine). A brush border enzyme is an enzyme located in the brush border that catalyzes reactions on the E face of the cell (sucrase, lactase, maltase, etc.)

How does glucose enter the cells lining your small intestine?

Sodium Potassium Pump- primary active transport + Sodium Glucose transporter- secondary active transport... SGLT uses potential energy from Na/K gradient to drag glucose into the cell

Light micrographs are obtained by directing photons through a specimen. In general, how are TEMs and SEMs obtained? What's the fundamental difference in the images obtained from these two different types of microscopes?

TEMS fire electrons at the tissue, allowing one to see through the specimen SEMS fire electrons at the surface of the tissue, allowing for a topographic view

Taxol is a long-standing treatment for cancer. How does it work? What are its drawbacks? What would be a better way to treat cancer?

Taxol works by binding to microtubules and freezing the mitotic spindle apparatus, thus the cancer cells cannot divide. The problem with this chemical is that it targets any dividing cell, including healthy ones. A better way to treat cancer would be to directly identify and target cancerous cells, as opposed to merely targeting any dividing cell of the body.

Can you explain how the mitochondria in your cells were once free-living bacteria? What are the lines of evidence that support the endosymbiotic theory?

The endosymbiotic theory proposes that purple non-sulfur bacteria were taken in by a larger host cell and they co-evolved together. Mitochondria have a double membrane, their own circular DNA, their own ribosomes and can divide on their own as well. They are also susceptible to antibiotic therapy just like bacteria.

What is the function of the Golgi apparatus? Are all proteins that leave the Golgi destined to leave the cell? If not, what are all of the potential fates of proteins that leave Golgi?

The golgi modifies, sorts, packages, and distributes proteins that it receives from the RER. Not all proteins leaving the golfi are destined to leave the cell... some go to lysosomes or to plasma membrane

Many individuals erroneously say that the heart is located inside the pericardial cavity. How would you correctly describe the heart in relation to the pericardial cavity? How does the pericardial sac fit into this picture?

The heart is not inside the pericardial cavity, but it is surrounded by the pericardial cavity. The pericardial sac is a membrane that surrounds the cavity and protects the heart

Information sent ahead in a pathway in anticipation for an event that has not yet occurred is referred to as feed-forward information. When you merely look at food, your stomach can start gurgling. How is feed-forward information transmitted from your eyes to your stomach?

The information is sent by the nervous system via the vagus nerve

Why do cells require a large surface area to volume ratio to exist? Some neurons are a meter long? That's a lot of cytoplasm! Do these cells defy this requirement and therefore have a low surface area to volume ratio?

The large surface area allows for more cell to cell communication between the internal and external environment. If the volume was high, there would be too much cytosol- it would be more difficult to communicate because the cell would be so large that diffusion would take longer. No, neurons have a large surface area as a result of their length.

How do the four nucleotides of DNA combine to form a double helix?

The nucleotides bind together through hydrogen bonds. Adenine and guanine are purines, cytosine and thymine are pyrimidines... A-T has 2 H bonds and C-G has 3

The pump-leak leak model is an extraordinarily important process in the human body. Can you explain the pump-leak model and its fundamental utility in the human body?

The pump-leak model essentially says that whatever is pumped out of the cell leaks back in. When Na+ leaks back into cells like muscle cells, they contract. Often, when an ion leaks back in, it drags another solute into the cell against its concentration gradient. This is seen with the SGLT.

What's the difference in resolution between your eye and a typical laboratory compound light microscope? Between a light microscope and a TEM?

There is a 1,000 fold difference. This is because human eye resolution is about 200 um, while a typical light microscope resolution is .24 um... in order to get from .24 to 200, multiply by 1000. 3 orders of magnitude It is a 1000 fold difference between a light microscope and a TEM

Draw one water molecule hydrogen bonding with two other water molecules. How many hydrogen bonds, ionic bonds, non-polar covalent bonds and polar covalent bonds are present in the entire group of interacting water molecules?

There will be 6 polar covalent bonds between the hydrogens and oxygen in each molecule. There will be two hydrogen bonds between the partial positive hydrogens and the partial negative oxygen on the different molecules.

An alien was discovered to vasoconstrict in response to an increase in its body temperature. Is this response human-like? In other words, is this a negative or positive feedback response? How do you know?

This is not a human like response. Humans typically use negative feedback response, which would oppose the change in body temperature, and work to maintain the setpoint. When body temperature increases, the blood vessels swell so that blood flows toward the skin and can be released into the air. The alien vasoconstricting is an example of positive feedback because it is enhancing the deviation from the setpoint.

What are the three components of a junctional complex? Which one is most apically located? Which one involves actin filaments? Which is primarily involved in preventing things from moving through the intercellular space?

Tight junctions: integral membrane proteins that bind to each other and run through the membrane (like a string of beads)... most apical Adherens junctions: integral membrane proteins that are attached to actin filaments that wrap around the cell (like a belt) Desmosome: intermediate filaments are attached to proteins

Is a glucose transporter (GLUT) a uniporter, symporter or antiporter? How does glucose enter your body cells?

Uniporter... glucose can not get across the membrane without a transporter since the membrane is hydrophobic; when glucose binds to GLUT, the conformation changes so that the glucose can fall in the cell. This is driven by concentration gradient. Once in the cell, a phosphate is attached to the glucose so that more glucose can be taken in by the cell

What vitamin deficiency leads to scurvy? Is this vitamin water- or fat-soluble?

Vitamin C... Vitamin B and C are water soluble; A, D, E, K are fat soluble

vitamin main functions (D, A, B, C, E, K)

Vitamin D is important for homeostasis of blood calcium (healthy bones and teeth... the sunshine vitamin) Vitamin A: healthy teeth, skin, eyes Vitamin B: digestion and metabolism, maintain nervous system Vitamin C: helps immune system... wound healing and iron absorption Vitamin E: protects against free radicals, helps form red blood cells Vitamin K: blood clotting, strong bones

Are vitamins considered cofactors or coenzymes? What vitamin is very important in the homeostasis of blood calcium levels?

Vitamins are coenzymes (facilitate enzyme function) Vitamin D is important for homeostasis of blood calcium (healthy bones and teeth... the sunshine vitamin)

One reductionist is studying the skeletal system and another the cardiovascular system. What emergent properties (i.e., functions that are only present when both systems work together in an integrated fashion) might both of these individuals be unable to identify in their respective systems?

blood calcium homeostasis

What is the difference in hydrogen ion concentration between a lysosome and the cytosol of the cell?

cytosol is about 7 and lysosome is 5 so its 100x (2 orders of magnitude)

In some regards, humans are much like combustion engines. How so?

gasoline (octane) is a hydrocarbon, meaning it is reduced. When oxygen is added, octane becomes oxidized which releases an explosion of energy. CO2 and water are byproducts. Humans are similar in this regard because mitochondria oxidize molecules such as glucose or fatty acids to generate energy. When ATP is produced, CO2 and H2O are byproducts

Which two monosaccharides combine to form lactose? What is the underlying pathology of lactose intolerance? What are some common symptoms of lactose intolerance? How can these symptoms be explained physiologically?

glucose + galactose Lactose intolerance develops when an individual does not have enough lactase in their brush border. Lactase is necessary to split the sugar molecule into its monosaccharides because only monosaccharides can be absorbed. In lactose intolerant people, the lactose is not split so it enters the small intestine where its breakdown produces many byproducts and gastrointestinal issues. Symptoms include gas, bloating, diarrhea, cramps. Bacteria used to digest the lactose causes gas, and water is attracted to the lactose in the large intestine so the individual experiences diarrhea.

What is the only type of functional group found in monosaccharides? What two functional groups interact to form a disaccharide? What is the specific name of the covalent bond that is formed between two monosaccharides to form a disaccharide?

hydroxyl in the cyclic form. hydroxyl and carbonyl in the chain form. hydroxyl groups interact to form a disaccharide. the covalent bond that forms is a glycosidic linkage

Total body water in a female is approximately 35 liters. Where is the vast majority of this water located in the female body?

intracellular fluid makes up about 28 L of water in the body

The surface of cells is covered with carbohydrates collectively referred to a glycocalyx. What types of conjugated carbohydrates comprise the glycocalyx? Mucus lines the surfaces of the body serving as a lubricant. Which conjugated carbohydrate is the primary component of mucus?

the glycocalyx is made up of glycoproteins and glycolipids. Mucus is made up of glycoproteins. The glycocalyx protects the cell, aids in cell recognition (antigens), and allows cell adhesion.