BIOCHEMISTRY LAB MIDTERMS

an important concept in chemistry that measures the acidity level of a solution.

measurement of pH

True or False: The pH of a subject is rated on a 14-point scale.

True

True or False: Solutions less than 7 is acidic and solutions more than 7 is base

True tf

a measure of how acidic or basic a chemical is when it's in an aqueous (water) solution.

pH

pH is measured using what? 2 answers possible

pH paper / pH meter

True or False: Most fruits, vegetables, and body fluids are acidic.

True

True or False: While pure water is neutral, natural water may be either acidic or basic. Cleaners tend to be basic.

True

True or False: All Liquids Have a pH Value

False

True or False: If there's no water, there's no pH.

True

The pH of urine and saliva is slightly acidic, around a pH of what?

6

Distilled water tends to be slightly _ because of dissolved carbon dioxide and other gases

acidic

Natural water rich in minerals tends to be _

alkaline or basic

Soil pH ranges from__

3-10

Most plants prefer a pH between__

5\.5 and 7.5

__contains hydrochloric acid and other substances and has a pH value of 1.2

Stomach acid

__may be prepared to maintain a pH

buffer solution

There are multiple ways to test the pH of substances. The simplest method is_

pH paper

Another method is to draw a small sample of a substance and apply drops of _

pH indicator

__are available to test liquids. Usually, these are designed for a particular application, like aquaria or swimming pools.

pH test kits

The most accurate method of measuring pH is using a__

pH meter

The equation for calculating pH was proposed in 1909 by__

Danish biochemist Søren Peter Lauritz Sørensen

The term "pH" comes from the German word "potenz," which means__

power

True or False: The acid or base molecule does not exist in an aqueous solution, only ions.

True

__completely dissociate in water, forming H+ and an anion.

Strong acids

__only partially dissociates in water to give H+ and the anion.

Weak acids

hydrofluoric acid, HF, and acetic acid, CH3COOH are all example of what?

Weak acids

hydrochloric acid, nitric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, perchloric acid are all example of what?

Strong acids

__dissociate 100 percent into the cation and OH- (hydroxide ion).

Strong bases

The hydroxides of the Group I and Group II metals usually are considered __

Strong bases

ammonia, NH3, and diethylamine, (CH3CH2)2NH are all example of what?

Weak bases

True or False: a mechanism within the body known as the bicarbonate buffering system keeps your blood's pH in check

True

__made up of a weak acid and its conjugate base or a weak base and its conjugate acid

buffer solution

__contains a bicarbonate buffer system

Blood

__is required for most enzymes to function correctly

buffered pH

you add this to another solution in order to balance its pH, its relative acidity, or its alkalinity.

buffer solution

To determine a buffer's pH--or extrapolate from its pH the concentration of any one of its components--you can make a series of calculations based on the__ equation

Henderson-Hasselbalch / buffer equation

True or False: A weak acid or weak base ionizes, or gives up hydrogen or hydroxyl ions, only slightly in water, while strong acids and bases ionize almost completely.

True

help maintain a steady pH around the physiological pH

Biological buffers

Most buffers are __ solutions composed of roughly equal amounts of a weak acid and the salt of its conjugate base.

aqueous

Buffer is also known as? CLUE: S-A

Shock-absorber

In buffer system, when added, the -OH reacts with the weak acid to form its conjugate base.

Base

In buffer system, when added, the H3O+ reacts with the conjugate base to form a weak acid.

Acid

ability to resist changes in pH is called

BUFFER ACTION

a system, usually an aqueous solution, that possesses the property of resisting changes in pH with the addition of small amounts of a strong acid or base.

BUFFER SOLUTION

ability of a buffer system to resist pH changes.

BUFFER CAPACITY/VALUE

True or False: The bigger the pH change caused by the addition of a given amount of acid or alkali, the greater the buffer capacity and vice versa.

False: should be smaller

To hold the pH of blood close to 7.4, the body uses three buffer systems__

(1) CARBONIC ACID-BICARBONATE SYSTEM, (2) DIHYDROGEN PHOSPHATE-HYDROGEN PHOSPHATE SYSTEM, (3) PROTEIN

True or False: CO2 is constantly produced by metabolic processes in the body. The amount of CO2 is related to the pH of the blood.

True

Blood pH less than 7.35 is called             

Acidosis- results when the body fails to eliminate enough CO2, due to lung disease or failure; indication of respiratory blockage, stroke, heart failure, diabetes, or renal disease.

Blood pH more than 7.45 is called

Alkalosis- is caused when very little CO2 is produced by the body; indication of vomiting, hyperventilation due to anxiety, hysteria, fever, exercise, or over dosage of antacids.

are the structural and functional units of all living organisms.

cells tf

True or False: all cells rely on the same basic strategies in order to survive: allow necessary substances in and permit others out, maintain their health, and replicate themselves.

True

made from the same major classes of organic molecules: nucleic acids, proteins, carbohydrates, and lipids.

Cells

Living cells contain an estimated __ different kinds of molecules in an aqueous environment confined by a cell membrane.

10,000

A cell membrane is a __-based structure that separates a cell’s aqueous-based interior from the aqueous environment surrounding the cell.

lipid

__are also commonly called plasma membranes because they separate the cytoplasm (aqueous contents) of a cell from its surroundings.

Cell membrane

controls the movement of substances into and out of the cell.

Cell membrane

Up to _% of the mass of a cell membrane is lipid material consisting primarily of the three types of membrane lipids.

80%

What are the three types of membrane lipids?

phospholipids, glycolipids, and cholesterol

__a two-layer-thick structure of phospholipids and glycolipids in which the nonpolar tails of the lipids are in the middle of the structure and the polar heads are on the outside surfaces of the structure.

lipid bilayer

__ regulate membrane rigidity. Because of their compact shape, __ molecules fit between the fatty acid chains of the lipid bilayer, restricting the movement of the fatty acid chains.

cholesterol

are responsible for moving substances such as nutrients and electrolytes across the membrane, and they also act as receptors that bind hormones and neurotransmitters.

proteins

They are found on the outer membrane and are covalently bonded to protein molecules or lipid molecules.

Oligosaccharides (small carbs molecules)

The carbohydrate chains extend outward from the membrane into the surrounding aqueous environment. Such carbohydrate-protein and carbohydrate-lipid combinations are called __

glycoproteins and glycolipids

True or False: All molecules in a living cell are lifeless.

True

All living organisms need __ to fully function

energy malamang

This is what drives biochemical processes.

energy

the collective term used as the sum of all of these chemical reactions

Metabolism

Metabolism is divided into two types, what are those?

anabolism and catabolism

Anabolism means __

building up

Catabolism means __

breaking down

Type of transport: From High Concentration to Low Concentration or Along with the Gradient Concentration

Passive

Also known as “downhill transport” and No energy required

Passive

dialysis, diffusion, filtration, hydrolysis, and osmosis are all example of?

Passive transport

Type of transport:


1. From Low Concentration to High Concentration or "Against" the Gradient Concentration;

Active

Utilized by pumps/carrier proteins; Also known as "uphill transport; Energy requiring;

Active

endocytosis, exocytosis, phagocytosis, and sodium-potassium pump are example of what?

Active transport

It is the movement of ions, small molecules (but not colloidal particles) and solvent, through a semi-permeable membrane.

DIALYSIS

DIALYSIS: Silver Nitrate Test   (1 mL dialysate +   1 mL AgNO3). What is the positive result?

white precipitate; \[+\]: compounds containing Cl ion, ex. NaCl; Dialysate will give a \[+\] result indicating the presence of  NaCl and other crystalloids.

DIALYSIS: Biuret Test (1 mL dialysate +   2 mL 10% NaOH  + 5 d CuSO4). What is the positive result?

Purple solution; \[+\]:    polypeptides; peptide bond/amide bond; Dialysate will give a \[-\] result indicating the absence of polypeptide bonds because the polypeptides present in the chicken bouillon are too big to pass through the semi-permeable membrane.

DIALYSIS: Ninhydrin Test (3  mL dialysate +   1 mL 0.2% Ninhydrin  + heat). What is the positive result?

blue-violet solution; \[+\]:  amino acids; Dialysate will give a \[+\] result since there is the presence of amino acids which are still small enough to pass through the semi-permeable membrane

An average of 180 liters of blood is purified daily by the kidneys. Soluble waste materials will pass thru but not proteins in the form of blood cells and plasma proteins. This is an example of what passive transport?

Dialysis

It is the process by which molecules in solution distribute themselves uniformly throughout a solution from an area of higher concentration to a region of lower concentration

Diffusion

This type of passive transport can be seen with very small (O2, CO2) & lipid-soluble molecules (steroids)

Diffusion

True or False: Temperature is inversely proportional to Rate of Diffusion

False- it is directly proportional, meaning the higher the temperature, the faster is the rate of diffusion

What are the other Factors Affecting Diffusion?

State of substance and its size

True or False: Gases diffuse faster than liquids

True

True or False: Size of particles is inversely proportional to rate of diffusion

True- the smaller is the size of a particle, the faster is the rate of diffusion

the movement of solvent/water molecules through a differentially permeable membrane from a region of  LOWER solute concentration to a region of HIGHER solute solution

Osmosis

True or False: Osmosis is being done in order to achieve isotonic

OSMOSIS: True or False: Hypertonic is achieved when 2.0% of NaCl is added to the blood

True

OSMOSIS: True or False: Hypotonic is achieved when 0.9% of NaCl is added to the blood

False: Isotonic is what’s achieved through the addition of 0.9% NaCl

OSMOSIS: True or False: Isotonic is achieved when 0.1% of NaCl is added to the blood

False: Hypotonic is what’s achieved through the addition of 0.1% NaCl

Crenation happens in Hypertonic

True

When blood swells in size and eventually bursts. What is it called?

Hemolysis

True or False: Drinking of seawater can lead to dehydration

True- water gets out of tissues to dilute the higher concentration of seawater causing dehydration

The reaction in which water is added to convert large/complex molecules into smaller/simpler and more usable molecules. Generally speaking, almost all digestive and degradative processes in the body occur by this reaction

Hydrolysis

HYDROLYSIS: Iodine Test- What is the positive result?

colored solution

HYDROLYSIS: Iodine Test- What is the positive result of Macaroni with SALIVA?

Dark-blue color and softest texture

HYDROLYSIS: Iodine Test- What is the positive result of Macaroni with NaCO?

Darkest blue color and soft texture