BIOL 1100 Unit 04 (Ch 14, 15, 16, 17)

Question 1

phage

Answer 1

(also, bacteriophage) virus that infects bacteria

Question 2

DNA monomer

Answer 2

nucleotide that uses deoxyribose

Question 3

RNA monomer

Answer 3

nucleotide that uses ribose

Question 4

DNA replication models

Answer 4

3 models (conservative, semi-conservative, and dispersive)

Question 5

Semi-conservative model (of DNA replication)

Answer 5

DNA replication where the two strands come apart – each acts as a template for synthesis of a new complementary strand.

Question 6

DNA base pairs

Answer 6

A-T, G-C

Question 7

RNA base pairs

Answer 7

A-U, G-C

Question 8

what is the flow of information in the cell

Answer 8

DNA encodes RNA, which in turn encodes protein.

DNA is first transcribed into mRNA.

then mRNA strands are then translated into proteins

Question 9

Transcription initiation

Answer 9

In transcription: When RNA polymerase binds to a specific region on DNA called the promoter, marking the start point for RNA synthesis (initiates RNA synthesis)

Question 10

transcription elongation

Answer 10

the stage of transcription where RNA polymerase adds nucleotides to an RNA strand to create a full RNA transcript

(RNA polymerase adds complimentary nucleotides (A, U, C, G) to make the mRNA)

Process:
RNA polymerase moves along the DNA template strand, adding a complementary RNA nucleotide (AUCG) to the 3’ end of the RNA strand for each DNA nucleotide.
Result:
The RNA transcript is almost identical to the DNA coding strand, but with uracil (U) replacing thymine (T) and a slightly different sugar.

Question 11

transcription termination

Answer 11

final step in the transcription cycle, where the RNA polymerase and the nascent RNA are released from the DNA template

(transcription ends when RNA polymerase transcribes a terminator sequence: The process stops and the mRNA is released)

Question 12

transcription (what and where)

Answer 12

transcription is the process of copying a gene’s DNA sequence into messenger RNA (mRNA). This process takes place in the nucleus of a cell.

Question 13

translation (what and where)

Answer 13

translation is the process of using the information in mRNA to produce a protein chain, or polypeptide. This process takes place in the cytoplasm of a cell

Question 14

codon

Answer 14

three consecutive nucleotides in mRNA that specify the

insertion of an amino acid or

the release of a polypeptide chain during translation

Question 15

anticodon

Answer 15

three-nucleotide sequence in a tRNA molecule that corresponds to an mRNA codon

Question 16

mutation

Answer 16

change in the nucleotide sequence of the DNA strands.

Question 17

base substitution

Answer 17

(also, Missense) type of point mutation; a type of genetic mutation where one nucleotide (base) in a DNA sequence is replaced with another, essentially swapping one “letter” of the genetic code for another at a specific position

(most common nucleotide mutation;
two types, either transitions or transversions.

Transition substitution refers to a purine or pyrimidine being replaced by a base of the same kind; for example, a purine such as adenine may be replaced by the purine guanine.

Transversion substitution refers to a purine being replaced by a pyrimidine, or vice versa; for example, cytosine, a pyrimidine, is replaced by adenine, a purine.

Question 18

frame shift

Answer 18

a genetic mutation that occurs when a DNA sequence is altered by the insertion or deletion of one or more nucleotides that is not a multiple of three;

(This disrupts the reading frame of the DNA sequence, which is the grouping of codons. drastically altering the reading frame and leading to a completely different amino acid sequence downstream.
Frameshift mutations are generally predicted to trigger more substantial clinical consequences than other types of mutations)

Question 19

RNA splicing

Answer 19

pre-mRNA is transformed into mature mRNA by removing introns and joining exons together

the process where a newly formed precursor messenger RNA (pre-mRNA) is transformed into a mature mRNA by removing non-coding regions called introns and joining the coding regions, known as exons, together to create a functional protein-coding sequence; essentially, it’s a form of RNA editing that removes unnecessary parts to produce the final message for protein synthesis

Question 20

Intron

Answer 20

non–protein-coding intervening sequences that are spliced from mRNA during processing; the non-coding segments removed during splicing

A sequence of DNA between exons that is copied into RNA, but is not part of the final mRNA transcript

Question 21

exon

Answer 21

sequence present in protein-coding mRNA after completion of pre-mRNA splicing; the coding segments that are joined together to form the mature mRNA

Question 22

how can one gene can code for many different polypeptides?

Answer 22

A single gene can code for multiple polypeptides through a process called “alternative splicing,” where different combinations of exons within the gene are spliced together during RNA processing, resulting in various mRNA molecules that translate into distinct polypeptides with potentially different functions; Splicing different combinations of exon together can lead to the production of a variety of different proteins being produced from a single gene

Question 23

Signal transduction pathway

Answer 23

the process by which a signal molecule binds to a receptor on the outside of the plasma membrane to initiate a chemical or physical series of molecular events through the inside of the cell; a series of molecular interactions that occur when a signaling molecule binds to its receptor on a cell’s surface. This process activates various intracellular pathways that are involved in cell signaling

Question 24

What initiates a Signal transduction pathway

Answer 24

a signal molecule binding to a receptor on the outside of the plasma membrane (cell surface)

Question 25

what is the function of a Signal transduction pathway

Answer 25

allows cells to **receive and interpret external signals**, like hormones or neurotransmitters, by converting them into intracellular responses, essentially enabling cells to **communicate** with each other and their **environment**, leading to specific cellular actions like growth, differentiation, or activation of specific functions within the cell

Question 26

What is the carcinogen known to cause the most cases and types of cancer

Answer 26

Tobacco

Question 27

plasmid

Answer 27

a small, **circular piece of DNA** that **exists separately from a cell's chromosomal DNA** and can **replicate independently**, often found in **bacteria** and carrying genes that provide advantages like **antibiotic resistance;** scientists frequently **use plasmids as vectors** to introduce specific genes into cells for research purposes

Question 28

vector

Answer 28

A **specialized plasmid** that has been **engineered to carry foreign genes into host cells**. Vectors are usually smaller than naturally occurring plasmids; an **artificially synthesized DNA molecule**

Question 29

recombinant DNA

Answer 29

**a DNA molecule that is created in a laboratory by combining DNA from different sources**. This process is called recombinant DNA technology, which involves using enzymes and other techniques to isolate and manipulate DNA segments combining DNA fragments that molecular cloning generates that do not exist in nature; also a chimeric molecule;

Question 30

cloned DNA

Answer 30

a copy of a specific DNA sequence that has been produced in large quantities using scientific methods

Question 31

transgenic organism

Answer 31

(aka GMOs) organism that receives DNA from a different species

Question 32

restriction enzyme

Answer 32

proteins that **cut DNA** at specific sequences, called **restriction sites**, **to produce fragments with known sequences at each end**

Question 33

reverse transcriptase

Answer 33

an **enzyme** that converts **RNA into DNA**, It's found in **retroviruses**, such as **HIV**, where it is used to integrate the viral RNA genome into the host cell's DNA by transforming it into a DNA copy

Question 34

how do vaccines work

Answer 34

by introducing a **weakened or inactive** version of a disease-causing organism into the body, which **triggers an immune response**. This response trains the body to fight the disease-causing organism, so that if the body is exposed to the organism in the future, it can **respond quickly**.

Question 35

Why does golden rice have a golden color? how was it created?

Answer 35

Rice has been genetically modified by adding genes into the DNA from daffodils and soil bacterium so that it produces beta-carotene (a precursor molecule to vitamin A), this makes the rice a golden yellow color

Question 36

gel electrophoresis:

Answer 36

Gel electrophoresis is a technique used to **separate DNA fragments of different sizes**. (DNA separate according to size; the smallest fragments will be farthest from the well (where the DNA was loaded), and the heavier molecular weight fragments will be closest to the well)

Question 37

Translation initiation

Answer 37

When a **ribosome assembles on mRNA and the first tRNA carrying an amino acid attaches**, initiating protein synthesis. (initiates protein synthesis)

Question 38

Translation elongation

Answer 38

a phase of **protein synthesis** that involves the **ribosome** moving along a **messenger RNA (mRNA) strand to create proteins** the stage where the amino acid chain gets longer. In elongation, the mRNA is read one **codon** at a time, and the amino acid matching each codon is added to a growing protein chain where amino acids are added to the growing chain in translation; The process begins when the second aminoacyl-tRNA binds to the A-site. During elongation, **amino acids are carried to the ribosome by tRNAs** and linked together to form a chain

Question 39

translation termination

Answer 39

the process in **protein synthesis** that ends when a **ribosome encounters a stop codon in the A site** and releases the completed **polypeptide chain**