BISC 101 Lab exam

Serological Pipette

Serological Pipette

Used to accurately dispense volumes of liquids

pasteur pipette

Used to dispense liquids when accuracy is less important , and to gently mix liquid mixtures by pipetting in and out

Preparing wet mounts on glass slides

To spread a sample thin enough ( between a glass slide and a glass cover slip) to view clearly under a microscope

A simple chemical test : Using Iodine to test for starch

To determine whether a sample contains starch
Starch= plant/veggies
No starch = animals

Cheesecloth and funnel filter instructions

Used to filter out larger solids while allowing liquids and smaller particles ( eg. Cells, organelles, etc) to pass through

how do molecules pass the membrane

active/facilitated transport, selective permeability of lipid bilayer, and concentration gradient

compound microscope

Used to view objects at 40x 100x or 400x magnification - to see cells

spectrophotometer

Used to measure how much light ( of each specific wavelength/colour) is absorbed by a sample. A prism is used to split the light, so that you can test one wavelength at a time across a wider range of possible wavelengths

eppendorf/IEC centrifuge

Used to separate the particles within a mixture into layers according to their relative densities, by spinning the mixture at extremely high speeds. The densest particles are found at the bottom of the table

Independent variable

The variable that is manipulated and its effect on the dependent variable is measured

Hypertonic

When the concentration of solute is greater outside than inside, water flows out= causes cell to shrivel and shrink in size

Hypotonic

When the concentration of solute is greater inside the cell than outside, water flows in= causes cell to swell and burst

isotonic

when the concentration of both the solute and solvent is equal so theres no net movement

What happens when you put a cell into a hypotonic solution?

fills to almost bursting

what happens when you put a cell into a hypertonic solution

shrivels

what happens when you put a cell into an isotonic solution

normal

the cell membrane is permeable to

Small hydrophobic molecules ( ex. O2, CO2 , N2 , Benzene)
Small uncharged molecules ( ex. H2O, glycerol)

the cell membrane is not permeable to

Large, uncharged molecules (ex. Glucose, sucrose)
Ions (ex. Cl-, K + , Na+)

why does Increasing the temperature increases the membrane permeability

o When raising the temperature, its fluidity increases, the atoms move faster including those that make up the phospholipid bilayers .
o This causes the membrane to be more fluid since the phospholipids are also moving and that it can be easily penetrated by other molecules

Why do you think a solute's solubility affects its ability to cross the RBC membrane ?

o A solutes solubility in oil affect its ability to cross the RBC membrane helps determine its polarity. Since Water is polar and oil is non polar , it means that the molecules are not attracted to each other. Thus, the more soluble in oil it is, the more polar the solute is.

What color are the P atoms in 3D molecule of DNA? what is phosphorus bonded to, to make a phosphate group?

- Purple
attached to the 5 carbon sugar at the 5th carbon (opposite to nitrogenous base /react-text
- it is made up of a P with 4O bonded to it to make a phosphorus group

What is the colour of the nitrogen atoms,

-Blue
-N is bonded to the first carbon of the 5 carbon molecule

what bond is in purine and pyrimidines

-A bonded to T by 2 hydrogen bonds (double bond)
-G bonded to C by 3 hydrogen bonds (triple bond)

what is N bonded to from nitrogenous base?

-It forms either A,T,C, or G base
-(A,G) = purine base (two rings)
-(T,C) = pyrimidine base (one ring)

What is the colour of carbon atoms ? how do carbon atoms bond together to make the 5 carbon sugar?

black, bonded to hydrogen atoms forming 5 carbon sugar

what is the colour of the hydrogen atoms and size

white and small

what is the colour of oxygen and its size

red and large

what nucleotides are on the 3D molecule of DNA ?

the phosphate group, the deoxyribose sugar, and the nitrogenous base

characteristics of purine base

adenine and guanine
double ring
A needs to double bonded to T
G needs triple bond to C

Characteristics of a pyrimidine base

-cytosine and thymine
-single ring
-C triple bond to G
-T double bond to A

Why will neither two purines nor pyrimidines pair together?

In order that the DNA maintain a diameter of about 2 nm across the double helix, it is necessary the smaller pyrimidines base pair with the larger purines. If two purines were to base-pair, the diameter of the double helix would be larger than 2 nm. Likewise, if two pyrimidines were to base-pair, the diameter of the double helix would be smaller than 2nm.
- two purines = too wide
- two pyrimidines = too narrow

Can you also explain why adenine does not base-pair with cytosine. and why thymine does not base-pair with guanine?

Hydrogen bonding, which holds the two DNA strands together, determines which nucleotides will form complementary base-pairs. Adenine is able to form two hydrogen bonds and so it lines up with thymine, which is also able to form two hydrogen bonds. Cytosine, which is a smaller nucleotide like thymine, does not base-pair with adenine because their hydrogen-bonding atoms would not line up correctly. Likewise, guanine is able to form three hydrogen bonds and so it lines up with cytosine. which is also able to form three hydrogen bonds. Guanine, which is larger like adenine, does not-base pair with thymine because their hydrogen-bonding atoms would not line up correctly.

How are individual nucleotide's joined together?

Nucleotides are joined together by covalent bonds between the phosphate group of one nucleotide and the third carbon atom of the pentose sugar in the next nucleotide

Transcription

the first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language

initiation-transcription

-binding of RNA polymerase to double stranded DNA; this step involves a transition to single strangeness in the region of binding; RNA polymerase binds at a sequence of DNA called promoter region.
- RNA pol 3 reads the top DNA strand (template) and binds to the promoter region with the help of transcription factors

Elongation - transcription

-nucleotides are added to the growing RNA chain. As the RNA polymerase moves down the DNA template strand, the open complex bubble moves also.
-in the 5'-->3' direction
-Thymine is replaced by Uracil in making mRNA = complimentary base

Termination - transcription

-a section of nucleic acid sequence that marks the end of a gene or operon in genomic DNA
-RNA pol reaches the termination sequence, releasing pre-mRNA made from DNA

RNA processing

-pre-mRNA undergoes RNA splicing where the introns are removed (non coding) bringing together the exons (coding)
- spliced transcript undergoes processing where a 5' cap and Poly A tail are added by enzymes (for protection)
-the now mature mRNA leaves the nucleus and heads into the cytoplasm for translation.

Translation

The second major step in gene expression, the mRNA is "read" according to the genetic code, which relates the DNA sequence to the amino acid sequence in proteins (Figure 2). Each group of three bases in mRNA constitutes a codon, and each codon specifies a particular amino acid (hence, it is a triplet code). The mRNA sequence is thus used as a template to assemble—in order—the chain of amino acids that form a protein.

initiation- translation

-complex for translation forms by the assembly of the ribosomal subunits and initiator tRNA (met-tRNA) at the start codon on the mRNA
-in the cytoplasm
-start codon = AUG
-moves in 5'-->3'
-tRNA binds the anticodons with the codons of the mRNA at each A site - bringing in corresponding amino acid

Elongation - translation

-the polypeptide chain begins by the appropriate aminoacyl-tRNA binding to the codon in the A site of the ribosome. /
-the formation of poly peptide at the P site /
-the empty tRNA with the growing poly peptide chain at the P site moves to the E site while the tRNA from the A site, with its corresponding amino acid, moves to the P site, adding amino acids to the growing polypeptide chain at the P site via peptide bonds --> releasing H2O /
-at the E site = the empty tRNA leaves amino acids at the p site to grow with the addition of new amino acids.

Termination - translation

-At a stop codon, a release factor reads the triplet, and polypeptide synthesis ends; the polypeptide is released from the tRNA, the tRNA is released from the ribosome, and the two ribosomal subunits separate from the mRNA.
-Polypeptide synthesis repeats until a stop codon is reached
-termination sequence is detected at the A site = UGA (stop codon) to anticodon ACU (release factor)

histones

function is to neutralize and condense DNA into chromatids

start codons

AUG ( methionine)

stop codons

UAA,UAG,UGA

RNA uses...

uracil instead of thymine in the coding strand

TATA box

-assists in directing RNA polymerase II to the initiation site downstream on DNA. RNA polymerases bind to regions of DNA known as promoters. Promoter regions are comprised of the initiation site and numerous nucleotides upstream from the initiation site. The TATA box is necessary for transcription because RNA polymersase II cannot recognize the initiation sites on its own. The TATA box directs the RNA polymersase II to the initiation site once the RNA polymerase has bound to the TATA box. Yet another promblem occurs when the RNA polymerase II scans for the TATA box. RNA polymerase II cannot recognize the TATA box on its own; it has to use transcription factors to find the TATA box. After the transcription factors bind to the TATA box, then RNA polymersase II can recognize and bind to the TATA box.

Enzymes

-proteins (nucleic acids) that can greatly increase the rates of reaction by acting as a chemical catalyst that lowers the activation energies of the reactions. They are essential to life because most metabolic reactions would not take place at all, unless the enzymes that catalyze them are synthesized.

What factors affect the rate of an enzyme catalyzed reaction ?

temperature, enzyme concentration, substrate concentration, and pH

temperature

: at higher temperatures the rate of reaction increases until reaching a too hot temperature which can denature the enzyme by changing the shape of the active site which results in a low reaction rate

enzyme concentration

as the enzyme concentration increases, the reaction rate increases linearly since there would be a higher amount of active sites for the substrate to bind to, making it less competitive for the substrates to bind to the active sites of the enzymes, thus speeding up the rate at which the substrate reacts

substrate concentration

the rate of reaction increases sharply and linearly with the addition of substrate, however the amount of enzyme is limited and becomes saturated with substrate, leaving no active sites to bind to which causes a plateau in the graph

pH

enzymes are easily effected by pH. especially if not optimal for that specific enzyme. At extremely high and low pH's the shape/structure of the enzyme/protein is effected as acid/base conditions disrupt hydrogen bonds between the loops of amino acid chains, distorting the active site of the enzyme, denaturing, which causes the substrate to not fit into the active site, limiting reactions.

Competitive inhibition

-binding of the inhibitor to the active site on the enzyme prevents binding of the substrate and vice versa. Most competitive inhibitors function by binding reversibly to the active site of the enzyme. /react-text
- ex, increasing the concentration of substrate /react-text
- or a compound of similar in structure as the substrate -- it will not denature the substrate

Allosteric inhibition

'modulators' in enzyme execution as they can attach themselves to a molecule that will alter the binding Site for the enzyme, rendering it unusable and therefore rendering the enzyme inactive.

Non competitive inhibition

the inhibitor reduces the activity of the enzyme and binds

Excretion

- the process by which the body removes nitrogenous waste products, deactivated drugs, toxins, and excess solutes from the body

Osmoregulation

- the process by which the body balances the intake and loss of water and solutes

nephron filtration

blood vessels form a ball of capillaries (called a glomerulus) within the cup-shaped end (the Bowman's capsule) of the nephron. The high blood pressure in this capsule causes some fluid to be pushed out of the blood vessel to be captured by the nephron. Since the glomerular capillary walls acted like a filter to keep blood cells and other large particles within the blood vessel, the fluid that escaped into the nephron is called the glomerular filtrate.

nephron reabsorption

The glomerular filtrate contains water and valuable solutes (e.g. glucose) that we do not want to lose. Therefore, an important function of the nephron is to reabsorb valuable solutes and water. Notice that the blood vessel that takes blood away from the glomerulus remains adjacent to the nephron, so that these reabsorbed solutes and water can efficiently move back into the blood by diffusion and osmosis.

nephron Secretion:

One way to conserve water is to concentrate as much metabolic waste into as small a volume of urine as possible. To do this, your kidney actively transports wastes into the filtrate as it is processed into urine.

nephron Excretion:

Once the filtrate has been processed through reabsorption and secretion, it becomes concentrated urine that is ready to be excreted from you body when you urinate.

digestion : mouth

Mechanical and chemical processing of food: break down of lipids and carbohydrates
Enzymes : salivary amylase(carbohydrates ), salivary lipase( lipids)

Esophagus

Transports food

stomach

mechanical and chemical processing - digest proteins
enzymes : pepsin ( proteins)

Small intestine

Chemical processing and absorption ( digest proteins, fats, carbohydrates; absorbs nutrients and water)
Enzymes : pancreatic amylase ( carbohydrates), bile salts ( lipids)
, pancreatic lipase ( lipids), Proteins - trypsin, chymotrypsin, elastase, and carboxypeptidase

Large intestine

absorbs water and form feces

rectum

hold feces

anus

elimination of feces

Salivary glands

secret enzymes that digest carbohydrates; supply lubricating mucus.
Enzymes: salivary amylase

liver

secretes molecules required to digest fats. Bile

Gallbladder

store secretions from liver: empties into small intestine

pancreas

secretes enzymes and other materials into small intestine

3 main tubes that are connected to each kidney

renal artery in, renal vein out, and ureter out

Renal artery in

• Contains oxygenated blood
• Comes from the heart
• Goes to the kidney

Renal Vein out

• Contains deoxygenated blood
• Comes from the kidney
• Goes to the inferior vena cava

Ureter out

• Contains urea
• Comes from the kidney
• Goes to the bladder

Distal convoluted tubule

As the filtrate moves through the distal convoluted tubule, more water, sodium ions, and bicarbonate ions may be reabsorbed, and more hydrogen ions secreted, as is necessary to maintain blood pH and osmolarity at homeostatic set points. This selective reabsorption is controlled by hormones

Collecting Duct

As the filtrate passes through the collecting duct, more water is reabsorbed and some urea leaks out into the interstitial fluid of the inner medulla. The reabsorption of water is controlled by antidiuretic hormone (ADH). Each collecting duct collects the processed filtrate, now called urine, from several nearby nephrons, and delivers the urine to the renal pelvis. From there, the urine from all collecting ducts is transported to the urinary bladder via the ureter.

Vital capacity

the maximum amount of air that you can expel in one breath

Tidal volume (TV

this is the amount of air inspired or expired during normal breathing

Expiratory reserve volume (ERV

the maximum amount of air you can expel after normal tidal expiration.

Inspiratory reserve volume (IRV)

the maximum amount of air you can inspire after normal tidal inspiration.

What parts of the heart are producing the two heart sounds?

The semilunar valves and atrioventricular valves

cardiac cycle first diastole phase

the atria and ventricles are relaxed and the atrioventricular valves are open. De-oxygenated blood from the superior and inferior vena cavae flows into the right atrium. The open atrioventricular valves allow blood to pass through to the ventricles. The SA node contracts triggering the atria to contract. The right atrium empties its contents into the right ventricle. The tricuspid valve prevents the blood from flowing back into the right atriu

cardiac cycle first systole phase

the right ventricle receives impulses from the Purkinje fibers and contracts. The atrioventricular valves close and the semilunar valves open. The de-oxygenated blood is pumped into the pulmonary artery. The pulmonary valve prevents the blood from flowing back into the right ventricle.
The pulmonary artery carries the blood to the lungs. There the blood picks up oxygen and is returned to the left atrium of the heart by the pulmonary veins

cardiac cycle second diastole phase

the semilunar valves close and the atrioventricular valves open. Blood from the pulmonary veins fills the left atrium. (Blood from the vena cava is also filling the right atrium.) The SA node contracts again triggering the atria to contract. The left atrium empties its contents into the left ventricle. The mitral valve prevents the oxygenated blood from flowing back into the left atrium.

cardiac cycle 2nd Systole Phase

-the atrioventricular valves close and the semilunar valves open. The left ventricle receives impulses from the Purkinje fibers and contracts. Oxygenated blood is pumped into the aorta. The aortic valve prevents the oxygenated blood from flowing back -The aorta branches out to provide oxygenated blood to all parts of the body. The oxygen depleted blood is returned to the heart via the vena cavae.

Respiratory

-increase absorption of Oxygen into the body by greatly increasing the SA for gas exchange (gills and lungs), and constantly bringing a fresh water or air supply in contact with these surfaces (breathing in and out)
-exchange systems are kept thing as possible to minimize diffusion distance

Circulatory system

-the use of muscular heart to circulate blood within the body, so that every cell is efficiently supplied with needed nutrients, and wastes are efficiently removed /react-text
-exchange system kept thing to minimize diffusion distance

main purpose of respiratory system

-to help animals exchange gases with the external environment: specifically to absorb O2 that is needed for cellular respiration, and to dispose of CO2 that is produced as a byproduct of cellular respiration

Gills

found in all fish and animals that live in water. as water passes over the great SA of the gills in one direction, blood flows through the gill capillaries in the opposite direction. = counter current exchange for absorbing O2 and removing CO2 /

lungs

found in all terrestrial vertebrates. air contains a much higher pp of O2 and is much less dense and less viscous than water. therefore, most terrestrial beings (humans) can energetically afford to move air in and out of our lungs, and to have gasses exchanged with the lung capillaries without a counter-current exchange system (birds are an exception)

Blood flows: through 2 sets of capillaries

1. located in the lungs or gills where O2 diffuses into the blood and CO2 diffuses out
2. all of the systematic capillaries, which deliver oxygen to ( and take CO2 from) all of the other tissues in the animal bodies

Fish circulatory system

oxygen poor blood returns from systematic capillaries and enters a simple 2 chambered heart ( one atrium and two ventricle) that pumps this blood into the gill capillaries. The oxygenated blood from the gill capillaries then enters the systematic capillaries via the aorta

Birds and mammals circulatory system

double circulation and 4 chambered heart; : two completely separated sides ( each has its own atrium and ventricle)

Amphibian circulatory system

-double circulation
-two atria feed into single ventricle
-there will be some mixing of oxygenated blood ( returning from the lung capillaries ) with oxygen poor blood ( returning from the systematic capillaries

Skeletal muscle

-under voluntary control
-found in the throat or pharynx and around the anus to control the passage of materials
-each muscle bundle consists of numerous muscle fibers bound together by connective tissue
-each muscle fiber is one long cell with several nuclei and many mitochondria
-can be very long
-muscle fibers are made up of myofibrils and each myofibril contains myofilaments of contractile protein's
-chief myofilament proteins are actin and myosin
-pattern of banding (seen in skeletal muscle longitudinal sections when viewed under the compound microscope) is the result of the regular arrangement of thick myosin and thin actin myofilaments.

Smooth muscle

o Under involuntary control
o Found on the walls of the gastrointestinal tract and uterus
o Responsible for the movement of materials, and in blood vessels, where they control the flow of the blood
o Muscle cells are spindle-shaped
o Lack the banded pattern of skeletal muscle
o Contain a single nucleus per cell

Cardiac muscle

o Under involuntary control
o Found in the walls of the heart, where the cells must contract almost simultaneously to efficiently pump blood
o Have a banded appearance like skeletal muscle cells, but they are short and may be branched
o Usually one nucleus per cell
o Must communicate with each other by electrical synapses, which appear as dark lines called intercalated disc in longitudinal sections of cardiac muscle