Physiology Exam 1: Cell Biology

What is the basic unit of all forms of matter?

Atom.

all living things are made of what

cells

everything (living or nonliving) is made of what - basic unit of matter

atoms

Name the three most stable subatomic particles.

Neutrons, protons, and electrons.

what charge is the nucleus

positive

What charge do electrons have and where do they orbit?

Negative; they orbit the nucleus in electron orbitals.

shared space around the nucleus that electrons occupy

electron orbitals

How many electrons are needed to stabilize Hydrogen and Helium in their outer shells?

2 electrons.

What determines the chemical behavior of an atom?

The number of electrons in the outermost shell.

An atom with what electron shell is reactive

an incomplete (partially full) electron shell

An atom with what electron shell is inert/not active

full shell

What happens when a reactive atom fills its valence shell?

It interacts with other atoms to form chemical bonds.

An attraction that holds two atoms together.

a chemical bond.

Two or more atoms held together by chemical bonds; the smallest unit retaining the properties of a compound.

a molecule

A charged atom or molecule formed by gain or loss of electrons.

an ion

Negatively charged; gained anelectron

anions

Positively charged; loses an electron

a cation

Attraction between oppositely charged ions.

an ionic bond

A bond formed when two atoms share pairs of electrons.

a covalent bond

Electrons shared equally; e.g., H2; no partial charges.

nonpolar covalent bond.

Electrons shared unequally; e.g., H2O; partial charges.

polar covalent bond

An atom’s ability to attract and hold electrons; a numerical value; higher means stronger attraction and determines whether a bond is polar or non-polar

electronegativity

Which four elements make up about 97% of the human body?

Hydrogen, Carbon, Nitrogen, Oxygen.

When the atoms in the bond are next to each other

(ex: H-C, C-N, and N-O)

nonpolar bond

If the atoms are separated by at least one atom on the list because their electronegativities are different enough that the electrons will be more attracted to one atom than the other (ex: H-N, C-O, and O-H)

polar bond

When a hydrogen covalently bonded to one atom is attracted to a second atom;

(it has to be attracted to more than one atom)

hydrogen bond (If hydrogen is connected to only one thing then it’s not a hydrogen bond)

The bond between hydrogen and oxygen in a SINGLE water molecule

polar covalent bond

The bond between hydrogen and oxygen in SEPARATE water molecules

hydrogen bond

strong bonds

Polar covalent bonds

weak bonds

hydrogen bonds

Polar substances dissolve in polar solvents; nonpolar in nonpolar solvents.

“like dissolves like” mean?

Having an affinity for water

hydrophilic (polar/ionic substances). affinity = likes water

Not having an affinity for water

hydrophobic (nonpolar substances). doesnt dissolve in water

a poor solvent for molecules which do not have charged regions

water

What phenomenon causes hydrophobic molecules to clump together in water?

Hydrophobic interactions.

Why doesn’t oil dissolve in water?

Oil is nonpolar and cannot form hydrogen bonds with polar water.

Name the four basic biomolecule types.

Carbohydrates, Lipids, Proteins, Nucleotides.

contains carbon, hydrogen, and oxygen in a 1:2:1 ratio

a monosaccharide  (ex: C6. H12. O6) 

What ratio defines monosaccharides?

Carbon, hydrogen, and oxygen in a 1:2:1 ratio.

major purpose for carbohydrates

short term energy (C 6 H 10 O 6 - not a monosacharride)

most important molecule in the human body

glycogen

Energy storage carbohydrate and is metabolized when blood sugar levels drop. Also stored in liver and skeletal muscle.

glycogen (think glucose)

The two stage process of increasing the amount of glycogen stored in your body before competition

carb-loading

A week or two prior to competition, intense exercise and a no-carb / high protein diet.

Depletion phase (think no carbs)

A couple of days before competition, no intense exercise, eating as many carbs as you can take in. 

Loading phase

Why does water weight occur during carb-loading?

Glycogen is polar and dissolves and attaches to water; up to about four ounces of water per ounce of glycogen.

nonpolar and has no water attached to it. 

fat

What is the metabolic energy-release sequence when burning energy?

Blood glucose first, then glycogen, then fat.

consist of Nonpolar hydrocarbon chains/rings; usually hydrophobic.

lipids (fats)

have no C=C (double) bonds and are solid at body temperature (a lot of hydrogens are attached to it)

Saturated fats

have at least one C=C (double bond) and are liquid at body temp.

unsaturated fats

Two fatty acids plus a phosphate group attached to glycerol; major component of cell membranes; amphipathic.

phospholipids (not entirely hydrophobic)

have hydophillic heads face outwards and hydrophobic tails facing eachother (aqueous emviorment)

Phospholipids

has 4 rings fused together (three six-carbon rings and one five-carbon ring) made from cholesterol and most are sex hormones like estrogen and testosterone

steriods

Composed of multiple amino acids polymers and

proteins

Sequence (order) of amino acids is determined by DNA through processes of what

transcription and translation (gene expression)

• Composed of an amino group, a carboxyl group, and a functional group or R group.

• Shape is the function

amino acids

What determines the properties of an amino acid?

The R (side chain) group. aka functional group

The sequence/order of amino acids.

primary structure

coils, folds, helixes, etc

secondary structure of a protein

The overall three-dimensional shape of a protein that dermines its function

tertiary structure of a protein (is the function)

only some proteins have this structure The arrangement of multiple polypeptide chains in a protein.

What is the quaternary structure of a protein?

what happens when a protein unfolds and its tertiary structure is destroyed by heat, changes in ph, etc

denaturation

What are nucleotides made of?

A five-carbon sugar, one or more phosphate groups, and a nitrogenous base.

Pyrimidines and purines.

What are the two categories of nitrogenous bases?

G-C, A-T

Nucleotides

Name pyrimidines and their general bases.

Cytosine (C) and Thymine (T) in DNA (pyrimidines).

Name purines and their general bases.

Guanine (G) and Adenine (A) (purines).

How do DNA and RNA differ in base pairing?

DNA: G-C and A-T pairs; RNA uses A-U instead of T.

What is the DNA backbone?

Sugar-phosphate backbone on the outside with bases inside. (think of front and baack cover of a book)

A length of DNA that codes for a specific protein.

a gene

What are chromosomes made of?

DNA and proteins.

Converting DNA into proteins via transcription and translation.

gene expression (making proetins)

happens first In the nucleus (DNA) and DNA gets converted into an RNA copy

transcription

happens on the ribosome in the cytoplasm and the RNA copy is used to make the protein

translation

tells RNA polymerase where to start transcribing

a promoter in transcription

RNA polymerase binds to promoter: tells the polymerase where to go

1st step of transcription

RNA polymerase then unzips DNA, separates double helix

2nd step of transcription

Free ribonucleotides bind complementary bases on the DNA strand (RNA nucleotides are added to new RNA strands)

3rd step of transcription

RNA polymerase moves down DNA.  new RNA molecule is synthesized G-C, A-U

4th step of transcription

The end result of transcription and an unprocessed transcript containing introns and exons.

pre-mRNA

What happens to introns during post-transcription processing?

Introns are removed (non coding DNA); exons join to form mature mRNA.

A 5' cap added to pre-mRNA to aid exit from the nucleus.

What is CAP?

A tail of adenine nucleotides added to the 3' end to stabilize mRNA and aid ribosome binding.

What is the poly-A tail?

A sequence of three nucleotides in mRNA that codes for one amino acid.

What is a codon?

what codes for ONE SPECIFIC amino acid to be added to the protein during translation. 

codons

found in tRNA

anti codons

found in mRNA

regular codons

 bringing in the correct amino acids to build the proteins during translation. 

tRNA

What is AUG?

The start codon; codes for methionine.

What are the stop codons?

UGA, UAG, UAA; signal termination and do not code for amino acids.

What are the three types of RNA involved in translation?

mRNA, rRNA, and tRNA.

what site holds the growing protein;

P site

what site receives the next amino acid.

A site

Initiation, Elongation, and Termination.

steps of translation = codons

What happens during peptide bond formation in translation?

Amino acids are joined by peptide bonds as the ribosome shifts along the mRNA.

What happens to tRNA during elongation?

tRNA at the P site is released; tRNA at the A site moves into the P site; a new tRNA enters the A site.

What happens at termination of translation?

A stop codon is reached; the ribosome releases the finished protein and the mRNA may be reused.

What is posttranslational processing?

After translation, proteins may be cleaved or modified (e.g., glycosylation) in the ER and Golgi.

What are the genome and proteome?

Genome is all genes of an organism; proteome is all proteins produced from the genome.