Biology- Exam 2: Ch 4-7

cytoplasm

jelly-like substance that contains dissolved molecular building blocks (proteins, nucleic acids, ions, etc.)

organelle

structures that carry out specialized functions within the cell; most are surrounded by a membrance

prokaryotic cell

(1) no nucleus or membrane-bound organelles

(2) dna is suspended in cytoplasm

(3) most are microscopic, single-celled organisms

eukaryotic cell

(1) have a nucleus and membrane-bound organelles

(2) dna is enclosed in nucleus

(3) may be uni- or multicellular organisms

cytoskeleton

flexible network of proteins that provide structure to eukaryotic cells

actin filaments, intermediate filaments, and microtubules

nucleus

storehouse for most of the genetic information in the cell

rough endoplasmic reticulum

interconnected network of thin, folded membranes that are studded with ribosomes; once a protein is produced, it moves into the lumen where it’s modified for folding and stability

synthesizes proteins

smooth endoplasmic reticulum

interconnect network of thin, folded membranes that are smooth (lack ribosomes) and produce lipids, as well as breaking down drugs, toxins, poisons, and alcohol

makes lipids

ribosome

site of and active participant in proteins synthesis (the linking of amino acids)

composed of rna and protein

non-membranous structure

golgi apparatus

closely stacked layers of membrane-enclosed spaces that process, sort, and deliver proteins

packages and distributes proteins

vesicle

small, membrane-bound sacs that separate some material from the rest of the cytoplasm, transporting the materials from place to place within the cell

specializes in moving products into, out of, and within a cell

mitochondrion

bean-shaped and have two membranes; carries out series of chemical reactions that creates energy (ATP) for the cells from oxygen and sugar

participant in cellular respiration

vacuole

a fluid-filled sac used for the storage of materials needed by the cell (water, food molecules, inorganic ions, enzymes, etc.)

central vacuole found in plant cells to equilibrate water diffusion with the environment

lysosome

membrane-bound organelle that contains digestive enzymes; ‘stomach’ of the cell

hydrolitic enzymes that break down waste

centrioles

cylinder-shaped organelles made of a set of nine triplets of microtubules; organize or ‘anchor’ microtubules

composed of microtubules

cell wall

rigid layer that gives protection, support, and shape to plant cells; made of the carbohydrate cellulose

structural cellulose

present in plant cells

chloroplast

site of photosynthesis; highly compartmentalized, similar to mitochondria… have inner and outer membranes, as well as stacks of disc-shaped sacs within the inner membrane

chlorophyll, photosynthesis- converts CO2 and light and h20 to produce sugar and oxygen, double membranes

cell membrane

also known as plasma membrane; a phospholipid bilayer that separates intracellular space from extracellular space; controls passage of materials into and out of cell

phospholipid

molecule composed of charged (polar) ‘head’ made of glycerol and phosphate group and a ‘tail’ made of two fatty acid tails that are non-polar

nucleoid

singular circle dna

nucleoplasm

fluid inside the nucleus

chromosomes

dna and protein- condensed visible with dye

chromatin

dna and protein- no condensed, invisible

nucleolus

produces ribosomes inside the nucleus

nuclear envelope

a double membrane that surrounds the nucleus in the cell

bound ribsomes

ribosomes attached to rough er

Monomer for dna/rna

nucleotides

a _______ ____ is a polymer of nucleotide monomers

nucleic acid

monomer for dna

deoxyribonucleotide

monomer for rna

ribonucleotides

phosphate group is bonded to _ carbon

5’

nitrogenous base is bonded to _ carbon

1’

nitrogenous base is the ________ group

variable group

nucleotides are composed of?

a phosphate group, a sugar, and nitrogenous base

dna is ______ stranded

double

rna is ______ stranded

single

what sugar group does rna have?

ribose

what sugar group does dna have?

deoxyribose

how do you tell the differentiate between the different sugars?

look at carbon 2’ for the difference

ribose has a ________ _____ attached to C 2’

hydroxyl group

deoxyribose has a ________ attached to C 2’

hydrogen

pyrimidines

Cytosine (C), Uracil (U) in rna, Thymine (T) in dna

purines

Guanine (G) + Adenine (A)

purines are ______ than pyrimidines

larger

how do you read dna/rna strands?

5’ —> 3’

the strand grows from the _ end

3’

which carbon bonds with a phosphate group?

carbon 3’

the condensation bond that occurs when joining a phosphate group forms a…

phosphodiester linkage (bond)

dna grows ____-________ to eachother

anti-parallel

what would be the anti-parallel pairing to 5’ ATTGGC 3’?

3’ TAACCG 5’

the phosphate + sugar bases are the outer piece of the dna molecule or “backbone”

true

dna has a overall electronegativity due to?

the phosphates; polar covalent bonds

dna is hydrophillic and has high solubility

true

the double helix is a _________ structure

secondary

________ bonds hold/ join the inner or “nitrogenous” groups

hydrogen bonds

G-C rich code would be stronger than a A-T rich code since G-C rich code would have a higher amount of hydrogen bonds

true

Adenine (A) and Thymine (T) / Uracil (U) can form how many hydrogen bonds?

2 hydrogen bonds

Cytosine (C) and Guanine (G) can form how many hydrogen bonds?

3 hydrogen bonds

How is the dna molecule stabilized?

hydrophobic interactions in the interior and hydrogen bonding between base pairs

what is the function of dna?

can store and transmit biological information; the information is required for the growth and reproduction of all cells

an rna secondary structure consists of a ____ and ____

loop (single stranded loop) and stem (double helix)

considered a hairpin structure

rna is shortlived in the cell; it can come and leave the nucleus.

true

rna tertiary structure

folds to form distinctive three-dimensional shapes

rna quaternary structure

associations between severall molecules

rna is structurally, chemically, and functionally intermediate between dna and proteins

true

rna function

information containing molecule and is capable of self-replication

can function as a catalytic molecule

-ribozymes are enzyme-like rnas

Enzymes that break down DNA perform hydrolysis reactions of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

The phosphodiester linkages of the DNA backbone would be broken.

Consider the DNA nucleotide sequence ATCGGATCGA. What does this sequence best represent?

The primary structure of DNA

DNA double helices are soluble in water. How do these physical properties reflect the chemical structure of the DNA molecule?

The charged phosphate groups and sugars of DNA are hydrophilic.

If radiactively tagged ¹⁴C-labeled uracil is added to the growth medium of cells, what macromolecule(s) will be labeled?

RNA

If a double-stranded DNA sample was composed of 10 percent thymine, what would be the percentage of guanine?

40

A section of one DNA strand has the sequence ACCGAGGTT. What is sequence of the complimentary strand?

TGGCTCCAA

Nucleic acids are polymers made up of which of the following monomers?

Nucleotides

what nitrogenous base will form complementary base pair with uracil in RNA synthesis?

Adenine

Which bond holds together deoxyribose and the phosphate of a nucleotide?

covalent

Two complimentary strands of DNA are held together by ____________.

hydrogen bonds

A young scientist studying the Herpes virus infection wants to make a cream to kill the Herpes viruses in the cold sore. Her cream contains an enzyme that breaks the phosphodiester bonds between the nucleic acid monomers.

She tries it on herself. The results showed that the cold sore disappeared! But her lip is not healing. Which of the following statements can explain this result? 

The cream also disrupted the covalent bonds between the monomer of her lip cells’ nucleic acids

What is the monomer of a carbohydrate?

monosaccharides

where is the carbonyl group in an aldose?

end of carbon chain

where is the carbonyl group in a ketose?

middle of carbon chain

what are isomers?

same formula with a different arrangement of atoms in the molecule and different properties

what is an example of isomers?

glucose (C-OH is pointed up) and galactose (C-OH is pointed down)

Triose

3 carbons

Pentose

5 carbons

Hexose

6 carbons

Example of a triose sugar

glyceraldehyde

example of a pentose sugar

ribose

sugars tend to form ring structures in aqueous solutions

true

alpha molecule

C-OH bond is pointed downwards

beta molecule

C-OH bond is pointed upwards

what causes a ring structure to form?

oxygen from the 5-carbon bonds to the 1-carbon

What is the bonding point of a ring structure?

C = O (carbon double bonded to oxygen)

The simplest polysaccharides are disaccharides because…

they’re comprised of two monosaccharides monomers

polysaccharides or complex carbohydrates are _________ of monosaccharides monomers

polymers

a polysaccharide is comprised _+ monosaccharides

3

what is a glycosidic linkage(bond)?

when a condensation reaction occurs between two hydroxyl (OH) groups; a covalent bond

alpha glycosidic linkage

C-O-C bond is pointed downwards

beta glycosidic linkage

C-O-C bond is pointed upwards

carbohydrates are full of _________ ______ and later converted to actual atp molecules

potential energy

plants store sugar as ______

starch