Chapter 2: Intro to Chemistry Flashcards
What is the difference between matter and mass?
Matter is anything that occupies space and has mass, whereas mass is the amount of matter in any living organism or nonliving thing
What are chemical elements?
These are substances that cannot be broken down into simpler forms by ordinary chemical means
How many different elements are normally present in the body?
26
What are the major elements of the body?
Oxygen
Carbon
Hydrogen
Nitrogen
What percentage of the body’s mass is comprised of the major elements?
96%
What are the lesser elements of the body?
Calcium
Phosphorus
Potassium
Sulfur
Sodium
Chlorine
Magnesium
Iron
How many trace elements are there in the body?
There are 14 elements in this category
Why is iodine important for the body despite it being a trace element?
This element is important for making thyroid gland hormones
What is the significance of oxygen in the body?
It is part of water and many organic molecules
It is used to generate ATP
It is a molecule used by cells to temporarily store chemical energy
What is the importance of carbon in the body?
This forms the backbone chains and rings of all organic molecules: carbohydrates, lipids, proteins, and nucleic acids
What is the importance of hydrogen in the body?
It is part of water and most organic molecules
In its ionized form, it makes body fluids more acidic
What is the importance of nitrogen in the body?
It is a component of all proteins and nucleic acids
What is the importance of calcium in the body?
Contributes to hardness of bones and teeth
In its ionized form, it is vital for blood clotting, releasing hormones, contracting muscles, and other processes
What is the importance of phosphorus in the body?
It is a component of nucleic acids and ATP
It is also required for normal bone and tooth structure
What is the importance of potassium in the body?
In its ionized form, it is the most plentiful cation in intracellular fluid, which is key for the generation of action potentials
What is the importance of sulfur in the body?
This is a component of some vitamins and many proteins
What is the importance of sodium in the body?
In its ionized form, it is the most plentiful cation in the extracellular fluid, which is vital in the generation of action potentials
What is the importance of chlorine in the body?
In its ionized form, it is the most plentiful anion in extracellular fluid, which is key for maintaining water balance
What is the importance of magnesium in the body?
In its ionized form, it is needed for the action of many enzymes
What is the importance of iron in the body?
In its ionized forms, it is part of hemoglobin and some enzymes
What is an atom
This is the smallest unit of matter that retains the properties and characteristics of the element
What are the two basic parts of an atom?
The nucleus and one or more electrons
What is a nucleus of an atom comprised of?
This is made up of positively charged proteins and neutral neutrons
Is the nucleus of an atom neutral, positively, or negatively charged?
This is positively charged
How is the atomic number of an atom determined?
This is determined by the number of protons in the nucleus
How is the mass number of an atom determined?
This is determined by the number of protons plus the neutrons
What are electron shells?
These are the regions around the nucleus in which electrons are more likely to move about within
How many electrons can be held in the first, second, and third electron shells?
In order: 2, 8, 18
What is an ion?
This is a particle that has a positive or negative charge due to unequal numbers of protons and electrons
What is a molecule?
This is a combination of atoms that share electrons
How many hydrogen and oxygen molecules are required to create 2 water molecules?
2 hydrogen molecules 2x(H2) and 1 oxygen molecule (O2) = 2x(H2O)
What is a compound?
This is a substance that contains atoms of two or more different elements.
Is oxygen (O2) a molecule, compound, or both?
It is only a molecule. Because it only has one type of atom, it cannot be a compound
Is water (H2O) a molecule, compound, or both?
It is both. Because it has atoms that share electrons, it is a molecule. Because it is a substance containing two types of atoms, it is also a compound.
What is a free radical?
This is an ion or molecule that has an extra unpaired electron in its outermost shell
Superoxide is an example of what, and how is it formed?
This is an example of a free radical, and it is formed by the addition of an electron to an oxygen molecule)
Why are free radicals destructive to other molecules?
Because there is an unpaired electron on the radical, it is unstable and will break apart important body molecules by giving up their unpaired electron, or by taking an electron from another molecule
What are disorders and diseases that are linked to oxygen-derived free radicals?
Cancer
Atherosclerosis
Alzheimer’s
Emphysema
Diabetes mellitus
Cataracts
Macular degeneration
Rheumatoid arthritis
Deterioration associated with aging
What are antioxidants?
These are substances that inactivate oxygen-derived free radicals
What are chemical bonds?
These are the forces that bind atoms of molecules and compounds together, resisting their separation
What makes an atom or molecule chemically stable?
This occurs when the atom or molecule has 8 electrons in its outer shell
What are the three general types of chemical bonds?
Ionic bonds
Covalent bonds
Hydrogen bonds
What are ionic bonds?
This is a force of attraction between ions of opposite charges
Describe the ionic bond process between two ions
When one ion donates its electron to have a more stable outer shell, it becomes positively charged. For example, when Na donates its one outer shell electron, it becomes positively charged.
When another ion accepts an electron to have a more outer shell, it becomes negatively charged. For example, when chloride accepts an electron to obtain 8 electrons in its outer shell, it becomes negatively charged.
The positive and the negative charge attract each other, creating an ionic bond.
Where are ionic bonds most commonly found? Why?
These are most commonly found in teeth and bones. They give strength to tissue.
What is an electrolyte? Why is it called this?
This is an ionic compound that breaks apart into cations and anions when dissolved. It is called this because it can conduct an electric current.
What is a covalent bond?
This is when atoms form a molecule by sharing one, two, or three pairs of their outer shell electrons.
What is the most common chemical bond in the body?
The covalent bond
What is a single, double, and triple covalent bond?
These describe the number of electron pairs that are being shared between two atoms. A single covalent bond has 2 electrons that are shared between two atoms, a double has 4 electrons shared, and a triple has 6 electrons shared.
What is a nonpolar covalent bond?
This is when two atoms attract electrons equally. No one atom attracts the shared electrons more strongly than the other.
What is a polar covalent bond?
This is when the sharing of electrons between atoms is unequal
What is a hydrogen bond?
This is a bond that forms when a hydrogen atom with a partial positive charge attracts the partial negative charge of neighboring electronegative atoms, usually oxygen or nitrogen.
A hydrogen bond does not involve the sharing of electrons
Which of ionic, covalent, or hydrogen bonds cannot bind atoms into molecules?
Hydrogen bonds are not strong enough for this
Where are hydrogen bonds important in the body?
Water molecules,
Different parts of large molecules like proteins and DNA to provide strength and stability
What determines the 3D shape of DNA and proteins?
Hydrogen bonds
What is a chemical reaction?
This is when new bonds form or old bonds break between atoms.
What are the two main forms of energy?
Potential energy
Kinetic energy
What is potential energy?
This is stored energy
What is kinetic energy?
This is the energy in motion
What is chemical energy?
This is a form of potential energy that is stored in the bonds of molecules
In chemical reactions, does breaking old bonds require an input of energy, or release energy?
This will require an input of energy
In chemical reactions, does forming new bonds require an input of energy, or release energy?
This will release energy.
What is a synthesis reaction?
This is when two or more atoms, ions, or molecules combine to form new and larger molecules
What is anabolism
This is the collective term for all of the synthesis reactions that occur in the body
Combining amino acids into proteins is an example of what?
Anabolism (synthesis reaction)
What is a decomposition reaction?
This is when a molecule is split apart
What is catabolism?
This is the collective term to describe the decomposition reactions that occur in the body
The breakdown of large starch molecules into small glucose molecules during digestion is an example of what?
Catabolism (decomposition reaction)
What is an exchange reaction?
This is a reaction that consists of both synthesis and decomposition reactions
What is a reversible reaction?
This is a reaction that can go in either direction under different conditions
How are the conditions of a reversible reaction notated?
Whatever is above or below the arrows indicates the condition needed to create that direction’s reaction
Which bonds are most commonly used in inorganic compounds?
Ionic or covalent bonds
What are two inorganic compounds containing carbon?
Carbon dioxide (CO2) and bicarbonate (HCO3-)
What type of bond do organic compounds always have?
These compounds always have covalent bonds
What are monomers?
These are identical or similar building block subunits of macromolecules
What bond holds monomers together to form macromolecules?
Covalent bonds
What are the properties that make water vital for life?
Great solvent
Participates in chemical reactions
Absorbs and releases heat very slowly
Requires large amount of heat to change from a liquid to a gas
Serves as a lubricant
Why is water an excellent solvent?
Because of the polar covalent bonds and its bent shape, it can interact with several neighboring ions or molecules
How does water participate in chemical reactions?
It is an active participant in some decomposition and synthesis reactions. The addition of water molecules helps to break down large molecules in digestion
What is hydrolysis?
This is a type of reaction in which water is added to a larger nutrient molecule, causing it to break down into smaller water molecules
Why is it important for water to absorb and release heat slowly
This helps the body to maintain homeostasis of body temperature
Why is it helpful for water to require a large amount of heat to change from liquid to gas?
When the water of sweat evaporates, it takes large amounts of heat with it, providing a great cooling mechanism
Why is water an important lubricant?
It plays a major part in saliva, mucous, and other lubricating fluids. This is especially important in the thoracic and abdominal cavities where there is a lot of contact and sliding between organs.
Describe what acids, bases, and salts dissociate into when dissolved in water
Acids dissociate into one or more hydrogen ions
Bases dissociate into one or more hydroxide ions
Salts dissociate into cations and anions, neither hydrogen or hydroxide
What is the normal pH range of blood?
7.35 to 7.45
What are buffers?
These are chemical compounds that quickly and temporarily bind H+ to remove the highly reactive and excess H+ from solution but not the body.
List the following human substances in order of decreasing acidity:
Urine
Vaginal fluid
Cerebrospinal fluid
Bile
Blood
Pancreatic Juice
Semen
Saliva
Vaginal fluid
Urine
Saliva
Blood
Semen
Cerebrospinal fluid
Pancreatic juice
Bile
What is the carbonic acid-bicarbonate buffer system?
Carbonic acid (H2CO3) acts as a weak acid, while bicarbonate (HCO3-) acts as a weak base. If there are excess H+, then HCO3- will bind the excess, whereas if there is a shortage of H+, H2CO3 can donate H+
What is acidosis?
This is a condition in which the blood drops below a pH of 7.35. This depresses the nervous system and may cause a person to become disoriented, comatose, or die
What is alkylosis?
This is a condition in which the blood raises above a pH of 7.45. This causes overstimulation of the nervous system and leads to nervousness, muscle spasms, convulsions, and death
What is the common ratio of carbon:hydrogen:oxygen in carbohydrates?
1:2:1
What are the three major groups of carbohydrates
Monosaccharides, disaccharides, and polysaccharides
Which major group(s) of carbohydrates are considered simple sugars?
Monosaccharides and disaccharides
Which major group(s) of carbohydrates are considered complex carbohydrates?
polysaccharides
What is the principal function of monosaccharides in the body?
They are a source of chemical energy for ATP generation, which fuels metabolic reactions.
Ribose and deoxyribose are examples of which organic compound? Specify its major group
These are examples of carbohydrates - monosaccharides
What is dehydration synthesis?
This is when water is formed and removed from components in a chemical reaction
Which chemical reaction occurs when glucose and fructose combine to make sucrose?
A dehydration synthesis
What is a hydrolysis reaction?
This is a chemical reaction that causes one molecule to split after the addition of water.
Which chemical reaction occurs when sucrose splits to make glucose and fructose?
A hydrolysis reaction
Glycogen is an example of what type of organic molecule? Specify its major group
Glycogen is a carbohydrate. It is a polysaccharide
Which chemical reaction in the body is used to break polysaccharides down into monosaccharides?
Hydrolysis
Where is glycogen stored in the body?
The liver and skeletal muscles
Starches are an example of what type of organic molecule? Specify its major group
This is a carbohydrate. It is a polysaccharide
Cellulosis an example of what type of organic molecule? Specify its major group
This is a carbohydrate. It is a polysaccharide.
What is the significant difference between simple sugars and polysaccharides?
Simple sugars are usually soluble in water and taste sweet, while polysaccharides are usually not soluble in water and do not taste sweet
Which body cells store glycogen?
Cells within skeletal muscles and the liver.
Which elements make up lipids?
Carbon, hydrogen, and oxygen
Name five different members of the lipid family
Triglycerides
Phospholipid
Steroids
Fatty acids
Fat soluble vitamins
What are the most plentiful lipids in the human body
Triglycerides
Which molecule is the body’s most highly concentrated form of chemical energy
Triglycerides
Describe the structure of a triglyceride
These are made up of three fatty acid molecules and one glycerol molecule.
Describe saturated fats, monounsaturated fats, and polyunsaturated fats
Saturated fats have only single bonds between carbon atoms
Monounsaturated fats have fatty acids with one double covalent bond between two fatty acid carbon atoms
Polyunsaturated fats contain more than one double covalent bond between fatty acid carbon atoms
Which type of fats occur mainly in meats and non skimmed dairy products
Saturated fats
Which type of fats occur mainly in olive oil, peanut oil, canola oil, most nuts, avocados
monounsaturated fats
Which type of fats occur mainly in corn oil, safflower oil, sunflower oil, soybean oil, and fatty fish
polyunsaturated fats
Which type of fat is associated with disorders such as heart disease and colorectal cancer?
Saturated fats
Which types of fat are thought to decrease the risk of heart disease?
Monounsaturated and polyunsaturated fats
Trans fatty acids are made from which type of fat?
Polyunsaturated fats
Which fats are associated with cardiovascular disease?
Saturated fats and trans-fats
What are the components of phospholipids
These are made up of a glycerol backbone, two fatty acids, and one phosphate group
Which molecule makes up much of the membrane of a cell?
Phospholipids
Describe the structure of a steroid
This has four rings of carbon atoms
Cholesterol, estradiol, and testosterone are examples of which type of organic molecule? Specify its major group
These are lipids - specifically steroids
Omega-3 and Omega-6 are examples of which type of organic molecule? Specify its major group
These are lipids. They are part of a group of fatty acids called essential fatty acids. They are both polyunsaturated fatty acids
Cis fatty acids are examples of which type of organic molecule? Specify its major group
These are lipids. Part of a group called the essential fatty acids. They are monounsaturated fatty acids
What are the benefits of omega-3 and omega-6?
They help to lower total cholesterol, raise high-density lipoproteins, decrease low-density lipoproteins, decrease bone loss, reduce inflammatory symptoms of arthritis, promote wound healing, improve some skin disorders, and improve mental functions
What are the benefits of cis fatty acids?
These help the body make hormone-like regulators and cell membranes
Which elements make up proteins?
Carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
Give examples of the many roles of protein in the body
They are largely responsible for the structure of body cells.
Enzymes speed up reactions
Antibodies help defend the body
Others contract muscles
Some hormones are proteins
What are amino acids?
These are the building blocks of proteins
Describe the structure of amino acids
These have an amino group (-NH2) at one end and a carboxyl group (=COOH) at the other end
What are peptide bonds?
These are the covalent bonds that join amino acids together, making more complex molecules
Peptide bonds are made from which type of chemical reaction?
Dehydration synthesis
What is a peptide?
This is a molecule consisting of two or more amino acids.
A dipeptide has two amino acids, tripeptide has three, and polypeptide contains a large number of amino acids.
How many peptide bonds are there in a tripeptide?
Two
Proteins are:
dipeptides?
tripeptides?
polypeptides?
They are polypeptides. They consist of 50-2000 amino acids.
How many amino acid substitutions are required to cause sickle-cell disease?
Just one
What is denaturation?
This is when a protein loses its characteristic shape due to temperature, pH, or ion concentration, causing it to become non-functional
What are catalysts?
These are substances like enzymes that can speed up chemical reactions without itself being altered
Enzymes are usually which type of organic molecule?
Proteins
What are the important properties of enzymes?
Specificity
Efficiency
Control
Describe how enzymes are specific
Enzymes each catalyze specific chemical reactions using specific substrates, leading to specific products.
Describe how enzymes are efficient
In optimal conditions, enzymes can catalyze reactions millions to billions times faster than similar reactions without an enzyme. One molecule can convert substrate molecules to product molecules as fast as 600 000 per second
Describe how enzymes have control
The rate of synthesis and concentration of enzymes are under the control of a cell’s genes.
Different substances in a cell an either enhance or inhibit activity of an enzyme.
Many enzymes exist in both active and inactive states in the cell - the rate that they switch between states is determined by the chemical environment in the cell
What are cofactors and coenzyme
These are nonprotein substances that many enzymes require to function properly.
Ions of iron, zinc, magnesium, or calcium are cofactors, while niacin/riboflavin, derivatives of B vitamins, act as coenzymes
What are the steps of an enzymes action?
- Substrates attach at the active site, making a temporary compound called the enzyme-substrate complex.
- Substrate molecules are transformed by the rearrangement of existing atoms, breakdown of substrate molecule, or combination of several substrate molecules into products of the reaction
- After the reaction is completed, the products move away from the unchanged enzyme, which is free to attach to another substrate molecule
What is an active site?
This is the specific part of an enzyme that catalyzes reactions
Describe lactose intolerance
Condition from lack of lactase. Undigested lactose retains fluid in the feces, leading to bacterial fermentation of lactose which creates gas. Symptoms can include diarrhea, gas, bloating, and abdominal cramps after having dairy
Describe the structure of nucleic acids
These are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorous.
It is comprised of repeating building blocks called nucleotides.
What are the parts of a nucleotide
One nitrogen base (ring-shaped molecules containing C, H, O, and N atoms)
A five carbon monosaccharide called deoxyribose or ribose
A phosphate group (PO43-)
Describe the structure of DNA
Comprised of two strands twisted in a spiral staircase structure called a double helix
Each strand is made of nucleotides that bind to the other strand through hydrogen bonding from the nitrogenous base pairs
Each nucleotide will have either adenine, thymine, guanine, or cytosine.
A-T
C-G
What do the strands of DNA consist of?
These are made up of alternating phosphate groups and deoxyribose portions of the nucleotides
What do the rungs of the DNA consist of?
These are consist of the paired nitrogenous bases, held together by hydrogen bonds.
What is a gene?
This is a portion of a DNA strand that gives specific function, like providing instructions to synthesize hormones.
What is a mutation?
This is a change in the sequence of nitrogenous bases.
How does RNA differ from DNA?
Single stranded
Contains ribose as its 5-carbon sugar in the nucleotide
Uses uracil (U) instead of thymine
Is copied by using DNA as a blueprint (while DNA is self-replicating)
What are the different types of RNA?
Messenger RNA (mRNA)
Ribosomal RNA (rRNA)
transfer RNA (tRNA)
What is ATP?
Adenosine triphosphate transfers energy from energy-releasing reactions to energy requiring reactions which maintain cellular activities
Describe the structure of ATP
Consists of 3 phosphate groups attached to adenosine. Adenosine is made of adenine and ribose
How does the energy transferring reaction of ATP occur?
This happens through hydrolysis of the last phosphate group (requires addition of water molecule).
Which enzyme catalyzes hydrolysis of ATP?
ATPase
What are some cellular activities that rely on ATP?
Muscle contraction
Movement of chromosomes during cell division,
Movement of structures within cells,
Transport of substances across cell membranes,
Synthesis of larger molecules from smaller ones
What is the mechanism that replaces ATP in the cell?
ATP synthase promotes the addition of a phosphate group to ADP.
Which process creates the energy needed to convert ADP into ATP?
Cellular respiration is the main supplier of this. It requires the breakdown of glucose.
