Chapter 17 Biology Review

Front 1

Transcription

Back 1

Synthesis of mRNA from a DNA template, occurs in the nucleus (also produces tRNA and rRNA)

Front 2

Translation

Back 2

synthesis of a polypeptide from a mRNA template, occurs in the cytoplasm w/ ribosomes

Front 3

What is information in gene used for?

Back 3

Making proteins

Front 4

DNA of each gene contains info to make ____

Back 4

one type of polypeptide (chain of amino acids)

Front 5

3 Types of RNA

Back 5

mRna -- messenger RNA

tRNA -- transfer RNA

rRNA -- ribosomal RNA

Front 6

Structure of RNA

Back 6

Single stranded, ribose is 5 carbon sugar, and Uracil replaces Thymine

Front 7

Where does transcription occur

Back 7

The nucleus

Front 8

RNA polymerase

Back 8

enzyme that synthesizes RNA by adding complementary nucleotides to template DNA, doesn't require primer like DNA polymerase

Front 9

What separates DNA?

Back 9

RNA polymerase,

Front 10

Transcription factors

Back 10

collection of proteins that mediate binding of RNA polymerase and initiation of transcription

Front 11

Transcription initiation complex

Back 11

Whole complex of transcription factors and RNA polymerase bound to promoter

Front 12

Promoter region

Back 12

sequence of bases upstream of gene to which RNA polymerase binds to initially

Front 13

What are the three steps of Transcription?

Back 13

1. Initiation

2. Elongation

3. Termination

Front 14

Initiation

Back 14

RNA polymerase binds to promoter on DNA and unzips the helix

Front 15

Elongation

Back 15

RNA polymerase lays down complementary bases

Front 16

Termination

Back 16

Terminator Sequence is laid down and everything dissociates

Front 17

RNA splicing

Back 17

Removal of certain portions of synthesized RNA carried out by spliceosome

Front 18

Introns

Back 18

Noncoding segments of RNA

Front 19

Exon

Back 19

Expressed regions of RNA

Front 20

What is used as a template for translation?

Back 20

mRNA from transcription

Front 21

Where does translation take place?

Back 21

The cytoplasm/ribosome

Front 22

Translation is the conversion from _______ to _____

Back 22

"language of nucleic acids" "amino acids"

Front 23

Codon

Back 23

Group of 3 nucleotides that codes for a specific amino acid

Front 24

How many different types of tRNA are there?

Back 24

45

Front 25

What are the critical sites on tRNA?

Back 25

Amino acid attachment site

Anticodon site -- 3 base sequence that is complementary to a codon on mRNA

Front 26

Ribosome

Back 26

organelle made of rRNA and proteins, consisting of small and large subunits, comes together during translation

Front 27

What is the "start" codon or amino acid?

Back 27

Methionine

Front 28

What is required for initiation of translation?

Back 28

GTP and other proteins

Front 29

Which subunit of the ribosome binds to mRNA first?

Back 29

The small subunit

Front 30

How is the Ribosome organized to receive tRNA?

Back 30

Into EPA --> enter at A (arrival), add to the polypeptide chain at P (partner), and leave at E (exit)

Front 31

What ends elongation/terminates translation?

Back 31

A nonsense/STOP codon is reached

Front 32

What recognizes these stop codons?

Back 32

Proteins called Release Factors

Front 33

Polyribosomes

Back 33

One mRNA can be translated by several ribosomes simultaneously

Front 34

Rate of polypeptide growth in bacteria

Back 34

20 amino acids per second

Front 35

In what type of cells can transcription and translation occur simultaneously?

Back 35

Prokaryotic

Front 36

Antibiotics

Back 36

Can inhibit protein synthesis in prokaryotes but not eukaryotes

Front 37

How many different codons are there?

Back 37

64

Front 38

What is the START codon?

Back 38

Methionine/AUG

Front 39

How many STOP codons are there?

Back 39

3

Front 40

Wobbling

Back 40

When a change in the third letter of a codon doesn't alter the encoded amino acid

Front 41

Mutations

Back 41

Rare, random events that change the base sequence of DNA

Front 42

Why are mutations rare?

Back 42

Complementary base pairing is accurate in replication, DNA polymerase proofreads, and there are several enzymes that repair DNA

Front 43

1st Class of Mutations

Back 43

Base pair substitutions

Front 44

Silent mutation

Back 44

Because genetic code is redundant, changing of 3rd base doesn't always change protein made

Front 45

Missense mutation

Back 45

If amino acid is altered from polar to nonpolar

Front 46

Nonsense mutation

Back 46

Major problem if STOP codon appears early on in gene, not so much if later

Front 47

2nd Class of Mutations

Back 47

Insertions or Deletions = change in the # of bases

Front 48

Frameshift Mutation

Back 48

deletion of one or a few bases that cause all subsequent codons to be misread

"The fat cat sat bat rat"

remove the "a"

"The ftc tst btr t"

Front 49

Consequences of Frameshift Mutation

Back 49

Minor change if nonsense is made late in genome

Major change if nonsense is made early in genome

Major change if all subsequent amino acids are different

Front 50

Mutagens

Back 50

Physical or chemical agents that affect DNA

Front 51

3 Types of Mutagens

Back 51

1. Ionizing Radiation

2. Ultraviolet radiation

3. Chemical agents

Front 52

Germline Mutations

Back 52

occur in gametes, passed on to other generations

Front 53

Somatic Mutations

Back 53

Occur in body cells, may be involved in cancer