Unit 2.1 Quiz 3

•RNA (like DNA) has a primary structure consisting of a sugar-phosphate backbone, but the presence of the -OH group on ribose makes RNA

-Much more reactive -Less stable than DNA

To make a copy of itself, the first living molecule had to:

-Provide a template that could be copied -Catalyze polymerization reactions that would link monomers into a copy of that template

Codon

-The group of three bases -Specifies a particular amino acid

•Phosphodiester linkage (bond) occurs between

-The phosphate group on the 5′ carbon of one nucleotide -And the -OH group on the 3′ carbon of another

The genetic code contains

-The rules that specify the relationship between a sequence of nucleotide bases in DNA or RNA -The corresponding sequence of amino acids in a protein

In nucleotides, the nitrogenous base is bonded to the ................carbon of the sugar

1'

Three components of a nucleotide:

1- A phosphate group 2- A five-carbon sugar 3- A nitrogenous base

Helix diameter is ............. Å

20

How many bases specify a single amino acid?

3

In nucleotides, the phosphate group is bonded to the .................carbon of the sugar

5'

The nucleotide sequence is written in the (5′ -> 3′/3′ -> 5′)direction Reflects the order that nucleotides are added to a growing molecule The nucleic acid's primary structure is the nucleotide sequence

5′ -> 3′

•Deoxyribonucleotides -The sugar is deoxyribose (deoxy means lacking oxygen) -The nitrogenous bases:

Adenine, Thymine (T), Guanine (G) , Cytosine (C)

For each turn of the helix, there are ............ base-pairs, rising by .......... Å.

Answer 1: 10 Answer 2: 34

RNA polymerase will always bind to the (5' to 3'/3' to 5') strand of the DNA (templet strand) so that it can synthesize the mRNA in the (5' to 3'/3' to 5') direction

Answer 1: 3' to 5' Answer 2: 5' to 3'

G always pair with ......... by ..........hydrogen bonds. => (answer 1) and G have equal amounts in a DNA

Answer 1: C Answer 2: 3

Two groups of nitrogenous bases at C1' 1. ...................: Adenine (A), Guanine (G) 2. .........................: Cytosine (C), Uracil (U), Thymine (T)

Answer 1: Purines Answer 2: Pyrimidines

•DNA codes for ................, which codes for ...................

Answer 1: RNA Answer 2: proteins

A always pair with ........ by ............... hydrogen bonds. => A and (answer 1) have equal amounts in a DNA

Answer 1: T Answer 2: 2

.................. has an -OH group bonded to the 2′ carbon ................. has an H instead at the same location a. ribose b. deoxyribose

Answer 1: a. ribose Answer 2: b. deoxyribose

According to the central dogma -An organism's .............. is determined by the sequence of bases in its DNA An organism's .................... is a product of the proteins it produces

Answer 1: genotype Answer 2: phenotype

The nucleotide sequence is written in the 5′ -> 3′ direction Reflects the order that ................. are added to a growing molecule

Answer 1: nucleotides

.................. are the building blocks of nucleic acids similar to how .................... are the building blocks of proteins

Answer 1: nucleotides Answer 2: amino acids

The two strands of the DNA double helix run in (the same/opposite) direction(s)...........................................

Answer 1: opposite Answer 2: one in the 5' to 3' direction, the other in the 3' to 5' direction.

The sugar-phosphate backbone is on the (inside/outside) of this double helix, and the heterocyclic bases are on the (inside/outside).

Answer 1: outside Answer 2: inside

The prefix "deoxy-" means that an .................... atom is missing from the ......................position

Answer 1: oxygen Answer 2: C2'

The sugar-phosphate backbone of a nucleic acid is directional One end has an unlinked 5′ ............... The other end has an unlinked 3′ ..............

Answer 1: phosphate Answer 2: hydroxyl

Proteins are ..................... made up of ........................ which are amino acids

Answer 1: polymers Answer 2: monomers

Important Properties of the Code §It is ..................... -One amino acid can be encoded by more than one codon §It is ................... -One codon never codes for more than one amino acid §It is nearly .................... -All codons specify the same amino acids in all organisms •With a few minor exceptions §It is ......................... -The first two bases are usually identical -When multiple codons specify the same amino acid

Answer 1: redundant Answer 2: unambiguous Answer 3: universal Answer 4: conservative

The bottom strand of DNA is used as the .................... to synthesize RNA Therefore, the sequence of RNA is the same as the (top/bottom) strand or ........................... strand of DNA, except U in replace of T

Answer 1: template Answer 2: top Answer 3: coding

The sequence of bases in a DNA molecule Specifies .............................. Which specifies ..................

Answer 1: the sequence of bases in an RNA molecule Answer 2: the sequence of amino acids in a protein

The hereditary information in DNA is copied to mRNA through .......................... The mRNA is then translated to protein through ........................ ..................... is the process where the order of the nucleotide bases is converted to the order of amino acids

Answer 1: transcription process Answer 2: translation process Answer 3: Translation

If one molecule of a DNA sample were composed of 20% thymine (T), what would be the percentage of guanine (G)? A) 10 B) 20 C) 30 D) 40

C) 30 Will see question like this on exam!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

information storage

DNA

Why does thymine have a methyl group and uracil does not?

DNA has a much longer lifetime expectancy (the entire time the cell is alive) but the live expectance of RNA is much shorter, because if the cell doesn't need that type of protein to be produced the RNA will be destroyed. The methyl group makes thymine more stable and also consumes more energy to be built

monomers of DNA, contain the sugar deoxyribose and form DNA

Deoxyribonucleotides

•There are two types of nucleotides:

Deoxyribonucleotides (monomers) -> Deoxyribose nucleic acid (DNA) (polymers) Ribonucleotides (monomers) -> Ribose nucleic acids (RNA) (polymers)

True or False? DNA molecules can also have a tertiary structure

False

True or False? The ratio of A's to T's and C's to G's are always one

False Reason it's not always one is because the DNA will have a telomere at the end of the string to protect the tip of the DNA from degradation. So the single strand will make the difference of the total

True or False? Purines always pair with purines and pyrimidines always pair with pyrimidines

False, Purines always pair with pyrimidines

True or False? Pyrimidines are larger than purines

False, Purines are larger than pyrimidines

True or False? RNA can't function as an information containing molecule

False, RNA (like DNA) can function as an information-containing molecule

True or False? The Sugar-Phosphate backbone is nondirectional

False, it's directional

.......................... form when nucleotides polymerize

Nucleic acids

What is the different between phosphodiester bonds & hydrogen bonds?

Phosphodiester bonds are backbones formed between phosphate group and sugar group on 2 sides of DNA ladder. Hydrogen bonds are formed between nitrogenous bases in the middle of the DNA ladder.

Sequence of deoxyribonucleotides; bases are A, T, G, C

Primary DNA structure

monomers of RNA, contain the sugar ribose and form RNA

Ribonucleotides

Two antiparallel strands twist into a double helix, stabilized by hydrogen bonding between complementary bases (A-T, G-C) and hydrophobic interactions

Secondary DNA structure

How does the sequence of bases in a strand of mRNA code for the sequence of amino acids in a protein?

The genetic code contains -The rules that specify the relationship between a sequence of nucleotide bases in DNA or RNA -The corresponding sequence of amino acids in a protein Codon -The group of three bases -Specifies a particular amino acid

What is the difference between the structures of ribose and deoxyribose?

The prefix "deoxy-" means that an oxygen atom is missing from the C2' position

Adenine a. purine b. pyrimidine

a. purine

Guanine a. purine b. pyrimidine

a. purine

The base uracil (U) is found only in a. ribonucleotides b. deoxyribonucleotides

a. ribonucleotides

The base thymine (T) is found only in a. ribonucleotides b. deoxyribonucleotides

b. deoxyribonucleotides

Cytosine a. purine b. pyrimidine

b. pyrimidine

Thymine a. purine b. pyrimidine

b. pyrimidine

Uracil a. purine b. pyrimidine

b. pyrimidine

DNA structure & function: The Watson-Crick Model DNA can store and transmit ...................

biological information

DNA -> RNA -> proteins

central dogma

The ................. helps to explains why one generation of organisms transfer their genetic information to the offspring or next generations.

central dogma

Phosphodiester linkage (bond) forms through ....................reaction, which means they release one water molecule when forming the phosphodiester bond

condensation

In cells, DNA coils around proteins that bind to the double helix, in many cases the DNA-protein complex folds into highly organized, compact structures. But DNA (does/does not) form tertiary structure on its own.

does not

True or False? A stop codon is an amino acid

false

•RNA's secondary structure results from

folding over of single strand, forming a hairpin structure •The bases of RNA typically form hydrogen bonds with complementary bases on the same strand

To make a copy of itself, the first living molecule had to: -Provide a template that could be copied -Catalyze polymerization reactions that would link monomers into a copy of that template •RNA is capable of both processes because

it has 3 structural levels and chemical complexity: -Most origin-of-life researchers propose that the first life-form was made of RNA.

information carrier

mRNA

What part of a nucleotide determines its unique chemical properties?

nitrogenous base

The nucleic acid's .................... structure is the nucleotide sequence

primary

Sequence of ribonucleotides; bases are A, U, G, C

primary RNA structure

active cell machinery

proteins

Most common are hairpins, formed when a single strand folds back on itself to form a double-helix "stem" and a single-stranded "loop"

secondary RNA structure

•RNA molecules can also have tertiary structure -Forms when

secondary structures fold into more complex shapes

•RNA (like DNA) has a primary structure consisting of a ........................., but the presence of the -OH group on ribose makes RNA -Much more reactive -Less stable than DNA

sugar-phosphate backbone

Folds that form distinctive three-dimensional shapes (RNA)

tertiary RNA structure

A particular stretch of DNA (a gene) contains the information to specify

the amino acid sequence of one protein

•The central dogma summarizes

the flow of information in cells

DNA structure & function: The Watson-Crick Model DNA carries the information required for .................................................................

the growth and reproduction of all cells

Genes are the blueprint of life of all organisms because

they have conserved genetic information that determine genetic traits since million years ago.

True or False? Both nucleic acids and proteins are polymers

true

True or False? RNA always exists in the single strand form

true

True or False? Ribose and Deoxyribose differ by a single oxygen atom

true

True or False? The central dogma links genotypes to phenotypes -A tiny difference in genotype may produce a large change in phenotype

true

True or False? The information encoded in the base sequence of DNA is not directly translated into the amino acid sequence of proteins

true

True or False? RNA molecules can also have tertiary structure

true (can function as an enzyme)

The double helix resembles a .............................................

twisted ladder, with the sugar-phosphate backbone making up the sides and the hydrogen-bonded base pairs, the rungs.

•DNA's secondary structure consists of

two antiparallel strands twisted into a double helix

DNA structure & function: The Watson-Crick Model • According to the Watson-Crick model, a DNA molecule consists of ...................................

two polynucleotide strands coiled around each other in a helical, screw like fashion

Important Properties of the Code

§It is redundant -One amino acid can be encoded by more than one codon §It is unambiguous -One codon never codes for more than one amino acid §It is nearly universal -All codons specify the same amino acids in all organisms •With a few minor exceptions §It is conservative -The first two bases are usually identical -When multiple codons specify the same amino acid

How Long Is a Word in the Genetic Code?

§There are 20 amino acids but only four RNA bases §A three-base code provides more than enough messages to code for all 20 amino acids §A three-base code is known as a triplet code

What Is a Nucleic Acid?

•A nucleic acid is a polymer of nucleotide monomers

•Ribonucleotides -The sugar is ribose -The nitrogenous bases:

•Adenine (A), Uracil (U), Guanine (G), Cytosine (C)

The First Life-Form?

•RNA's structure makes it an extraordinarily versatile molecules, with diversity of roles in cells. •To make a copy of itself, the first living molecule had to: -Provide a template that could be copied -Catalyze polymerization reactions that would link monomers into a copy of that template •RNA is capable of both processes because it has 3 structural levels and chemical complexity: -Most origin-of-life researchers propose that the first life-form was made of RNA. https://www.youtube.com/watch?v=VYQQD0KNOis