Test 1 Flashcards
Name adaptations of animals to survive at high temperatures. Describe in more details one chosen example of animal species living in environment with such high temperatures.
High Temperatures
-Ability to produce highly concentrated urine
-Minimizing faecal water loss
-Use of alternative water sources
-Metabolic Water
-Microhabitat selection
-Estivation
Camel:
Concentrated urine and very dry faeces: the camel produces urine that is more concentrated than seawater, with a U/P ratio of about 8. The camel also produces the driest feces known!
Dehydration tolerance: camels can tolerate a water loss equivalent to 25% of their body weight, thanks to the use of metabolic water produced from fat metabolism (adipose tissue in the hump). A dehydrated camel may drink even 30% of its body weight at one time.
Body temperature fluctuation: Unlike most other mammals, the camel’s body temperature can fluctuate by as much as 6-7oC on a daily basis (camel’s body temperature will drop to about 34oC during the night and reach about 41oC in mid-afternoon.
Insulation: The camel’s fur, ranging from 30 – 100 mm in thickness, plays an important role in insulating the camel from gaining heat. The light colour of fur is also important because it reflects solar radiant energy rather than absorbing it.
Draw the structural formula of Galactose in Fisher’s and Haworth’s projection and characterize structural properties and biological functions of this monosaccharide
Function:
Converted into glucose in the liver, where it is metabolised.
Synthesized in mammary epithelial cells during lactation, to form the milk sugar – lactose
Component of Glycoproteins and glycolipids
Will Trehalose show reducing properties in the Benedict’s test? Explanation should include information about the structural composition of the carbohydrate
No, Trehalose will not reduce.
A free aldehyde group with an adjacent hydroxyl (-OH) can be oxidized to a carboxilic acid by an oxidizing agent such as: Benedict’s reagent.
Then the Cu2+ is reduced to Cu+ , which forms a brick-red precipitate of Cu2O, and a carbohydrate which takes part in this reaction is called a reducing sugar
Fructose (ketohexose) is also a reducing sugar. Usually a ketone cannot be oxidized, however, in Benedict’s solution, which is basic, a rearrengement occurs between the ketone group on carbon C2 and the hydroxyl group (OH) on carbon C1. As a result, fructose is converted to glucose, which produces an aldehyde group with adjacent hydroxyl that can be oxidized.
Reducing sugars:
-Galactose
-Glucose
-Glceraldehyde
-Fructose
-Ribose
-Xylose
What is the structure and function of Chitin?
Chitin is a structural homoglycan found in the exoskeletons of insects and crustaceans, as well as in the cell walls of most fungi and red algae.
It is a linear polymer of made up of β-(1→4)-linked N-acetyl-Dglucosamine (GlcNAc) residues, and its structure is similar to cellulose.
Each GlcNAc residue is rotated 180 degrees relative to its neighbours. The N-acetyl-D-glucosamine residues in adjacent strands of chitin form hydrogen bonds with each other resulting in linear fibrils of great strength.
Name all non-polar branched aliphatic amino acids. Draw a structural formula of a dipeptide composed of alanine and one branched aliphatic amino acids.
Valine
Leucine
Isoleucine
Describe the structure and function of collagen
Collagen consists of amino acids bound together to form a triple helix of elongated fibril known as a collagen helix. It is a rigid, inextensible fibrous protein that is a principal constituent of connective tissue in animals, including tendons, cartilage, bones, teeth, skin and blood vessels.
Type I collagen consists of two identical peptide chains designated α1 and one different chain designated α2.
Type I collagen predominates in bones, tendons and skin.
Type II collagen is found in cartilage,
Type III collagen is found in blood vessels and consist of three identical polypeptide chains.
Nearly one residue out of three is a glycine, and the proline content is also unusually high. Three unusual modified amino acids are also found in collagen: 4-hydroxyproline (Hyp), 3-hydroxyproline, and 5-hydroxylysine (Hyl). Proline and Hydroxyproline together compose up to 30% of the residues of collagen. Interestingly, 4-hydroxyproline (Hyp), 3-hydroxyproline, and 5-hydroxylysine (Hyl) are formed from normal proline and lysine after the collagen polypeptides are synthesized. The modifications are effected by two enzymes: prolyl hydroxylase and lysyl hydroxylase.
Because of their high content of glycine, proline, and hydroxyproline, collagen fibers are incapable of forming traditional structures such as α-helices and β-sheets. Instead, collagen polypeptides intertwine to form a unique right-handed triple helix, with each of the three strands arranged in a left-handed helical.
Describe the principle of one of the methods used to detect tryptophan in a solution
Test-
Explain which properties of water connected with hydrogen bonds are important for living organisms?
Cohesion
Cohesion is an attraction between molecules of the same substance. Cohesion is responsible for surface tension. Surface tension - Water droplets will resist rupture when stress and pressure are added to the system. Cohesion occurs when water is surrounded by air. The molecules that exist on the ends of droplets have fewer opportunities to form hydrogen bond. This causes their hydrogen bonds to strengthen; the surface is able to withstand tension.
Adhesion
Adhesion is the bonding of water molecules to another substance.
This happens because hydrogen bonds break and reform with great frequency. This constant rearranging of hydrogen bonds allows a percentage of all the molecules in a given sample to bond to another substance. This causes capillary action, the ability of a liquid to flow against gravity in a narrow space.
Density
The hydrogen bonds in water cause solid water to form a 3D matrix.
The hydrogen bonds keep the bonds spread out, not allowing water to condense, but rather forcing it to spread. When water is in a liquid state, hydrogen bonds are much more flexible and able to move around. When water becomes a solid, the bonds become less flexible, causing the water to expand.
High Specific Heat Capacity
A high specific heat capacity means that water is able to withstand a high amount of energy before its temperature is changed. In order for water to be heated up, hydrogen bonds must be broken. This additional energy needed to break the bonds gives water the ability to withstand temperature changes.
Relatively High Boiling Point
Draw the structural formula of Ribose in Fisher’s and Haworth’s projection and characterize structural properties and biological functions of this monosaccharide
Structural:
Function:
Structural components of
nucleic acids
Mono- and dinucleotides
Co-enzymes
Will Maltose show reducing properties in the Benedict’s test? Explanation should include information about the structural composition of the carbohydrate
yes as Maltose is a reducing disaccharide - it contains glycosidic bond between anameric hydrogen bond and a non anameric group of a second. it will be reducing as it has a free hemiacetal group (O-OH)
What is the difference between amylose and cellulose? Describe their structure and function
Cellulose - the major component of rigid cell walls that surround plant cells. Cellulose is a polymer consisting of long, unbranched chains of D-glucose connected by β(1→4) glycosidic bonds. Cellulose from wood pulp has typical chain lengths between 300 and 1700 units; cotton and other plant fibers as well as bacterial cellulose have chain lengths ranging from 800 to 10,000 units.
Amylose - a linear polymer of glucose, linked mainly by α(1→4) bonds that promote the formation of helix structure. Several thousand glucose molecules less readily digested than amylopectin but is preferred for storage in plants as it takes up less space (30%) iodine test -> starch
Name all sulphur containing amino acids. Draw a structural formula of a dipeptide composed of alanine and one sulphur containing amino acids.
Cysteine
Methionine
Draw - alanine-cysteine
What is the difference between primary and secondary structure of proteins? Characterize shortly these structures
X
Describe the principle of a method used to distinguish pentoses from hexoses
Bials test - Resorin and heat. if yellow its a hexose eg. fructose or glucose. if it goes green its a pentose eg arabinose.
What is metabolic water? When is it formed and what is its role in living organisms?
Water that results from the oxidation of organic materials by living organisms. It is recognized as a component of the total water income of animals.
