BIOL 110 - Exam 1

Element

substances that can’t be broken down into simpler substances by ordinary chemical reactions

Which of the following is an example of an element?

Oxygen

Atom

smallest unit of an element that retains that element’s chemical properties

Neutrons

Neutral

Protons

Positive

Electrons

Negative

Each atom is identified by its number of what within its atomic nucleus. It is written as a subscript to the left of the chemical symbol.

Protons

The periodic table is a chart of the elements arranged in order by what?

Atomic number

Atomic Number

Number of protons (electrons) in atomic nucleus.

Atomic Mass

protons + neutrons, expressed in atomic mass units or Daltons

What is the Atomic Number?

6

What is the symbol? 

C

What is the Atomic Mass?

12

How do you get the neutrons from an elements atomic mass and atomic number?

Take the mass subtracted by protons

Isotopes

exist because most elements consist of a mixture of atoms with different numbers of neutrons and therefore different masses

Radioisotopes

unstable isotopes that are unstable and decay to a more stable isotope usually becoming a different element that emit radiation when they decay

Radioisotopes can be substituted for their nonradioactive counterparts, making them a valuable research tool

True

Electrons move through regions of three dimensional space or what?

orbitals (“electron clouds”)

The energy of an electron depends on the orbital it occupies, called the what?

electron shell

Why do electrons in a shell with a greater average distance from the nucleus have a greater energy?

Energy in required to move an electron further away from the nucleus

The most energetic electrons occupy the what?

valence shell

First shell holds a maximum of how many electrons?

2

Second shell holds a maximum of how many electrons? 

8

changes in electron energy

energetic conversion

The chemical behavior of an atom is determined by the number and arrangement of its what electrons?

valence

Atoms with a full valence shell are stable

2 for hydrogen or helium, 8 for any other atom

Diatomics

H₂ N₂ F₂ O₂ I₂ Cl₂ B₂

Compund

chemical combinations of atoms of different elements in a fixed ratio

Molecule

chemical combination of two or more of a similar atom

Chemical bonds

force of attraction atoms are held together by

Number of valence electrons equals?

number of bonds an atom can form

Bond Energy

energy needed to break a chemical bond

Covalent Bond

sharing of electrons between atoms in which each has filled a valence shell

Electronegativity

measure of an atoms attraction for shared electrons in chemical bonds

Non-polar covalent bonds

electrons are shared equally

Polar covalent bonds

differ in electronegativity and creates bonds with dissimilar ends (poles) that vary in charge

Cation

positively charged ion, tends to lose electrons 

Anion

negatively charged ion, tends to gain electrons

Ionic Bonds

form as a consequence of the attraction between the positive charge of a cation and the negative charge of an anion

Ionic compound

is a substance consisting of anions and cations bonded by opposite charges

Ionic compounds tend to what into individual ions when placed in water 

dissociate

Hydrogen bonds

form between an atom with a partial negative charge and a hydrogen atom that is covalently bonded to O or N

Hydrogen bonding is a special type of which type of bond?

Polar covalent

LEO says GER

Loss electrons oxidation, Gain electrons reduction

Transfer of energy equals 

transfer of electron 

Compare the physical properties (mass and charge) and locations of electrons, protons, and neutrons

Protons and neutrons are located together in the atom's central nucleus, while electrons are found in orbitals or shells that surround the nucleus

Define and describe an atom’s electron shell and relate electron shells to energy levels

distinct energy level, or region around an atom's nucleus, where electrons are found

Explain how the number of valence electrons of an atom is related to its

chemical properties.

because these are the electrons involved in chemical bonding and reactions

Describe the properties of carbon that make it the central component of organic compounds.

its four valence electrons allow it to form up to four stable, covalent bonds with other atoms, including itself, enabling it to form diverse chains and rings. C-C bonds have freedom of rotation.

Define functional group and identify the role of functional groups in molecular diversity

a specific cluster of atoms within a larger molecule that determines the molecule's unique chemical properties and reactivity

Carbohydrates

composed of carbon, hydrogen and oxygen, with a ratio of hydrate of carbon 2:1, monosaccharides (single sugars like glucose, fructose, and galactose), disaccharides (two sugars linked together like sucrose), and polysaccharides (starches) quick energy for cells

Lipids

carbon and hydrogen, with a high proportion of carbon and hydrogen, making them hydrophobic. Lipids include triglycerides (fats and oils), phospholipids (components of cell membranes) Lipids serve as long-term energy storage

Proteins

composed of amino acids, which are linked together by peptide bonds. There are 20 different types of amino acids, each with a unique side chain that determines the protein's structure and function. primary (amino acid sequence), secondary (local folding like alpha helices and beta sheets), tertiary (overall folding of a polypeptide chain), and quaternary (interaction between multiple polypeptide chains) enzymes, structural components (e.g., collagen), transporters, hormones, and antibodies.

Isomers

compounds with the same molecular formula but different structures

Functional group

a group of atoms that help determine the types of chemical reactions and association in which the compound participates

Macromolecules

polymers (many) which are produced by linking small organic compounds monomers (1)

Humans lack the ability to break down cellulose what is that ability 

enzymes 

Chitin

is a modified carbohydrate that forms the external skeletons of insects, crayfish and anthropods

Phospholipid

consist of a glycerol molecule attached to two fatty acids (hydrocarbon

chain with carboxyl group, -COOH) at one end and a phosphate group at the other end. Hydrophilic head Hydrophobic tail.

Phospholipids are critical components of the what?

cell membrane

Saturated fatty acids tend to be __________ at room temp. These include animal fat and vegetable shortening

solid

Unsaturated fatty acids tend to be ________ at room temperature because double bonds inhibit aligning with other chains

liquid

Proteins are composed of amino acids that contain what?

Amino Groups and a Carboxyl Group bonded to a carbon

Primary Structure very important

linear sequence of amino acids joined by peptide bonds

4 Levels of organization for proteins? 

primary, secondary, tertiary and quaternary

The biological activity of a protein can be disrupted by a change in

amino acid sequence (primary structure)?

Sickle cell anemia is a genetic disease caused by a mutation that causes the substitution of the amino acid valine for glutamic acid at position 6. This makes hemoglobin more likely to form crystal structures, causing a “sickle” shaped RBC.

Nucleic Acids

Transmit hereditary information, determine instructions for protein formation, act in cell signaling and metabolism

The basic unit of nucleic acids are what?

sugar + phosphate group + nitrogenous base

Molecules of nucleic acids are made of nucleotides joined by what?

phosphodiester linkages

Describe the cell theory

1. all organisms are composed of one or more cells

2. The cell is the basic unit of organization and function in all living things

3. All cells are produced by the division of preexisting cells

Explain the functional significance of cell size and shape

A cell's size, limited by its surface-area-to-volume ratio, dictates how effectively it can transport nutrients in and waste out. Variations in cell shape are a strategy for increasing ratio of surface area to volume.

Prokaryotic

single cell, has no nucleus, don’t contain membrane bonded organelles

Eukaryotic 

multi-ceulluar more often, has a nucleus, organelles are smaller

Plant cells

have a rigid cell wall for structural support, a large central vacuole for water regulation, and chloroplasts for photosynthesis

animal cells

lack these features but possess lysosomes for digestion and centrosomes for cell division

Ribosomes 

protein production 

function of cell membranes

Why are cells small?

If the cell is too big it’ll take too long to move across, leave and enter the cell, inefficient if the cell was larger

cell membranes

control what enters and exits

nucleus

contains genetic form of DNA and controls protein synthesis by transcribing information from DNA into mRNA. Surrounded by nuclear envelope that separates nuclear contents from cytoplasm. Studded by nuclear pores that regulate passage of large materials across nuclear membrane. Contain nucleoli (singular = nucleolus) for production of rRNA.

ribosomes

Responsible for protein manufacturing within the cytoplasm, Contain enzymes needed to form peptide bonds, which join amino acids to form proteins. Found free in the cytosol or attached to cytoplasmic membranes. Consist of a large subunit and small subunit Number of ribosomes within a cell can be adjusted to meet metabolic need.

endomembrane system

a network of organelles that exchange materials through small membrane-enclosed transport vesicles. Vesicles act to route contents to its destination. Fusion of transport vesicle with target

causes release of contents. ER, Golgi Complex, Lysosomes, mitochondria, chloroplasts, plasma membrane

lysosomes

compartments for digestion. without them waste can’t leave properly

vacuoles

“empty”, Membrane-enclosed, fluid-filled sacs that lack internal structure, Particularly important in plants for: Structural support [take in water, pushing outward on cell wall] Storage [pigments, compounds, waste products

mitochondria

facilitate energy conversion, powerhouse of the cell, Grow and reproduce independently, produce ATP through aerobic respiration

chloroplasts

facilitate energy conversion, convert light energy into chemical energy via photosynthesis, Present in algae and plant cells, Contain chlorophyll, a pigment that traps light energy for photosynthesis

cytoskeleton

Dense network of protein fibers that support cell shape and ability to move, Important in cell division and transport of materials within the cell

Consist of 3 major types of protein filaments: microtubules, microfilaments, intermediate filaments

Plant color is a result of

chloroplast number

SA:V

the concept of the surface area to volume ratio; As an object's size decreases, its SA:V ratio increases. This is because as volume grows, surface area does not increase as rapidly

fluid mosaic model

a cell membrane consists of a phospholipid bilayer of phospholipid molecules in which proteins are embedded or otherwise associated.

Relate properties of the lipid bilayer to properties and functions of cell membranes

Biological membranes are composed of phospholipid molecules that form a bilayered structure. Lipid bilayers resist forming free ends and are self-sealing (form closed vesicles) and also flexible (change shape without breaking). These properties allow lipid bilayers to facilitate transfer of material through membranes

Describe the ways that membrane proteins associate with the lipid bilayer.

There are major groups of membrane proteins based on how tightly they are associated with the lipid bilayer:

Integral membrane proteins are bound to the membrane and are amphipathic. They can be transmembrane, extending completely through the membrane. Some span the membrane multiple times in the form of an alpha helix. Some form beta-pleated sheets.

Peripheral membrane proteins are not embedded in the lipid bilayer but are located on the inner or outer surface of the plasma membrane. They are usually bound to exposed regions of integral proteins via noncovalent interactions – easily removed

Describe the importance of selectively permeable membranes.

The fluid mosaic structure of biological membranes allows them to be selectively permeable, allowing only some substances to pass through. A cell can regulate chemical traffic across its plasma membrane, allowing control over molecular composition

Contrast simple and facilitated diffusion with active transport

In simple diffusion, small non-polar (uncharged) solutes move through the membrane, down their concentration gradient.

In facilitated diffusion, a transport protein makes the membrane permeable to a specific solute (ion, polar molecule). Net movement is still from an area of high solute concentration to an area of low solute concentration.

In active transport, the cell must expend metabolic energy to move materials from a region of low concentration to a region of high concentration, against the concentration gradient, with energy provided by ATP

Isotonic solutions

equal solute concentration to the fluid within a cell → no net movement of water; the cell will not shrink or swell.

Hypotonic solutions

lower concentration of dissolved materials than the cell → water will enter the cell and cause it to swell (burst).

Hypertonic solutions

higher concentration of dissolved materials than the cell → water will leave the cell and cause it to dehydrate and shrink

Form = Function

The lipid bilayer is self-sealing (form closed vesicles) and flexible (change shape without breaking).

Because of this form, the function is that it can facilitate transfer of material through membranes and also compartmentalize the cell without leaking

What is energy used to move in passive transport

concentration gradient

tonicity

relative solute concentration of a solute