4 Basic Genetic Mechanisms

Question 1

it is important in the normal functioning of the body.

Answer 1

synthesis of proteins

Question 2

-is the basis for the synthesis of proteins.

-It serves as the template to direct its replication and also provides the blueprint for the synthesis of proteins by its ability to direct the process of transcription and translation.

-consists of a chain of four kinds of nucleotides based on the type of nitrogenous bases.

Answer 2

DNA

Question 3

is composed mostly of chromosomes, structures that provide the inherited and individual characteristics of an animal.

Answer 3

nucleus

Question 4

DNA is made up of

Answer 4

two long polynucleotide chains.

Question 5

Each nucleotide is composed of

Answer 5

one molecule of phosphoric acid

one molecule of deoxyribose

one of the four bases.

Question 6

In the nucleus, the cell’s machinery copies the gene sequence into messenger RNA (mRNA), a molecule that is similar to DNA. Like DNA, mRNA has four nucleotide bases - but in mRNA, the base uracil (U) replaces thymine (T)

Answer 6

TRANSCRIPTION

Question 7

-The protein-making machinery, called the ribosome, reads the mRNA sequence and translates it into the amino acid sequence of the protein. The ribosome starts at the sequence AUG, then reads three nucleotides at a time. Each three nucleotide codon specifies a particular amino acid. The “stop” codons (UAA, UAG and UGA) tell the ribosome that the protein is complete.

-is the formation of the polypeptide from mRNA.

Answer 7

TRANSLATION

Question 8

This process is described to be semiconservative because each strand of a DNA double helix serves as a template for the synthesis of a complementary strand of DNA and each new DNA molecule consists of one old strand and one new strand.

Answer 8

DNA Replication

Question 9

DNA replication starts with ____(what enzyme) unwinding of two strands by ____ formed between the complementary bases.

Answer 9

DNA helicase

breaking hydrogen bonds

Question 10

what keeps DNA strands from binding again the whole topoisomerase preventing the supercoiling of the single strand of DNA.

Answer 10

Single-stranded binding proteins (SSBPs)

Question 11

what is the enzyme that binds to the single-strand DNA attaches free nucleotides into a new strand of DNA based on complementary base pairing in a strictly 5’ to 3’ direction.

Answer 11

DNA polymerase

Question 12

*DNA Replication

The unwinding of the double-stranded DNA forms two strands of DNA in two different directions called the

Answer 12

leading strand

lagging strand

Question 13

*DNA Replication

the new strand is assembled continuously

Answer 13

leading strand

Question 14

*DNA Replication

What do you call the new DNA strand that is assembled in many pieces (Okazaki fragments)

Answer 14

lagging strand,

Question 15

enzyme that seals the pieces of a lagging strand

Answer 15

DNA ligase

Question 16

is a segment of a DNA molecule that contains the information required for the synthesis of a functional biological product (protein or RNA).

Answer 16

gene

Question 17

-sugar of a slightly different composition used in the formation of RNA

-contains an extra hydroxyl ion appended to the ribose ring structure.

Answer 17

ribose

Question 18

In RNA, Thymine is replaced by another pyrimidine, ____

Answer 18

uracil

Question 19

Four different types of RNA

Answer 19

Messenger RNA

Transfer RNA

Ribosomal RNA

MicroRNA (miRNA)

Question 20

*Type of RNA

carries the genetic code to the cytoplasm for controlling the type of protein formed. Long, single RNA strands that are suspended in the cytoplasm are composed of several hundred to several thousand RNA nucleotides in unpaired strands; they contain codons that are exactly complementary to the code triplets of the DNA genes.

Answer 20

Messenger RNA,

Question 21

*Type of RNA

-transports activated amino acids to the ribosomes to be used in assembling the protein molecule; a carrier to transport specific types of amino acid to the ribosomes

-recognizes a particular codon on the messenger RNA

-a small molecule with a cloverleaf appearance

-Anticodon:

Answer 21

Transfer RNA,

Question 22

*Transfer RNA

specific code in the transfer RNA that allows it to recognize a specific codon (a triplet of nucleotide bases combine loosely by hydrogen bonding with the codon).

Answer 22

Anticodon:

Question 23

*Type of RNA

along with about 75 different proteins, forms ribosomes, the physical and chemical structures on which protein molecules are assembled. This constitutes about 60 percent of the ribosome manufacturing plant.

Answer 23

Ribosomal RNA,

Question 24

*Type of RNA

are single-stranded RNA molecules of 21 to 23 nucleotides that can regulate gene transcription and translation acts to decrease gene expression.

Answer 24

MicroRNA (miRNA),

Question 25

-this starts when RNA polymerase and regulatory proteins attach to a promoter (a specific binding site in DNA close to the start of a gene). -process of a nucleotide sequence of a gene used to synthesize a complementary strand of RNA. -is the formation of mRNA from a single DNA strand.

Answer 25

Transcription

Question 26

What is the enzyme that moves over the gene in a 5' to 3' direction, unwinds the DNA helix, reads the base sequence, and joins free RNA nucleotides into a complementary strand of mRNA.

Answer 26

RNA polymerase

Question 27

In transcription, each transcript is an RNA copy of a

Answer 27

gene

Question 28

is a sequence of three mRNA nucleotides that codes for a specific amino acid. The order in mRNA determines the order of amino acids in a polypeptide chain.

Answer 28

codon

Question 29

The process of translation includes the role of what types of RNA

Answer 29

tRNAs and rRNA.

Question 30

*Translation, type of RNA ____ has an anticodon complementary to an mRNA codon, and a binding site for the amino acid specified by that codon.

Answer 30

tRNA

Question 31

Translation occurs in the cytoplasm of cells and has three stages which are

Answer 31

Initiation Elongation Termination

Question 32

*stage of translation The small ribosomal subunit binds to the start of the mRNA sequence. Then a tRNA molecule carrying the amino acid methionine binds to what is called the start codon of the mRNA sequence. The start codon in all mRNA molecules has the sequence AUG and codes for methionine. Next, the large ribosomal subunit binds to form the complete initiation complex.

Answer 32

Initiation.

Question 33

*Stage of translation The ribosome assembles a polypeptide chain as it moves along the mRNA. Each corresponding amino acid is added to the growing chain and linked via a bond called a peptide bond. This continues until all of the codons are read.

Answer 33

Elongation.

Question 34

*Stage of translation When the ribosome encounters a stop codon, polypeptide synthesis ends. This occurs when the ribosome reaches a stop codon (UAA, UAG, and UGA). Since there are no tRNA molecules that can recognize these codons, the ribosome recognizes that translation is complete. The new protein is then released, and the translation complex comes apart. Release factors bind to the ribosome. Enzymes detach the mRNA and polypeptide chain from the ribosome.

Answer 34

Termination.

Question 35

The polypeptides synthesized from translation will undergo ____ to produce an active or final form of proteins.

Answer 35

post-translational modification

Question 36

-If the nucleotide sequence of gene changes, it may result in an altered gene product, with harmful effects. -are small-scale changes in the nucleotide sequence of a cell’s DNA that alter the genetic code.

Answer 36

Mutation

Question 37

Common mutations:

Answer 37

base-pair mutation deletion insertion

Question 38

type of mutation that may result in a premature stop codon or a different amino acid in a protein product.

Answer 38

base-pair substitution

Question 39

type of mutation which can cause the reading frame of mRNA codons to shift, changing the genetic message.

Answer 39

deletion or insertion

Question 40

example of a disorder caused by base-pair mutation

Answer 40

sickle-cell anemia.

Question 41

example of a disorder caused by deletion or insertion mutation

Answer 41

Huntington’s disease.

Question 42

Causes of mutation:

Answer 42

transposable elements (segments of DNA that can insert themselves anywhere in chromosomes), spontaneous mutations (uncorrected errors in DNA replication), harmful environmental agents such as ionizing radiation, UV radiation, and chemicals.

Question 43

two types of nucleic acids found in the body?

Answer 43

DNA and RNA