Test 2 Semester 2

Question 1

What roles do telomeres play in DNA replication?

Answer 1

telomeres prevent replication from skipping the ends of the DNA sequence

Question 2

What differences are there between DNA &and RNA

Answer 2

RNA has ribo nucleic acid, and ribose sugar unlike DNA,

and instead of thymine it has Uracil

Question 3

What are the 4 functions of DNA polymerase?

Answer 3

1-To code DNA
2-to catalyze cell’s reactions in the cell
3- to check for mistakes when coding
4-helping to transfer DNA to RNA

Question 4

What are the three bases of tRNA called that are complimentary to 3 bases on mRNA?

Answer 4

Thynine – Adenine
Guanine – Cytosine
Adenine – Uracil

Question 5

What is transcription?

Answer 5

When a strand of DNA is used as a template to make a complimentary strand of RNA

Question 6

What is Translation?

Answer 6

Translation is when the ribosome uses mRNA to make codons into amino acids which will form a polypeptide chain.

Question 7

What causes translation to stop?

Answer 7

stop codons

Question 8

Give at least one example of a stop codon:

Answer 8

UGA
UAA
UAG

Question 9

What are mutations?

Answer 9

Heritable changes in genetic information

Question 10

What does a cell use to decode DNA?

Answer 10

RNA

Question 11

What does RNA do?

Answer 11

Protein synthesis

Question 12

What is the first step in making proteins from DNA?

Answer 12

A cell must copy part of a DNA molecule into RNA

Question 13

What is the second step in making proteins from DNA?

Answer 13

RNA uses the instructions to produce proteins

Question 14

What are the three main types of RNA?

Answer 14

Messenger RNA (mRNA):carries info from DNA to other parts of the cell
Ribosomal RNA (rRNA): make up ribosomes, where proteins are made
Transfer RNA (tRNA): transfer the amino acids to the ribosome when they are building proteins

Question 15

How does the cell make RNA?

Answer 15

Transcription

Question 16

Where is RNA made in prokaryotes and eukaryotes?

Answer 16

Prokaryotes: cytoplasm
Eukaryotes: Nucleus

Question 17

What happens to RNA before it is sent out into the cell to make proteins?

Answer 17

Called pre-mRNA

RNA is edited and the pieces known as introns are removed, and the remaining pieces called exons are spliced together

Question 18

What makes up proteins?

Answer 18

Long chains of amino acids called polypeptide chains that determines the properties of different proteins

Question 19

How many different 3 base codons are possible?

Answer 19

64

Question 20

How are genetic messages decoded?

Answer 20

base sequence is transcribed from DNA to RNA

the transcribed info contains the code for making proteins

Question 21

What is an example of a start codon?

Answer 21

AUG

Question 22

Where does the ribosome come into play and what does it do?

Answer 22

Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains
(this is known as translation)
once complete the chains fold into their appropriate protein shape

Question 23

Steps of Translation:

Answer 23

• DNA is transcribed into mRNA in the nucleus
• mRNA is then sent to the cytoplasm
• ribosome attaches to mRNA
• Codons pass through the ribosomes (they are being read)
• tRNA brings the appropriate amino acid for every codon
• Ribosome attaches the amino acids to the growing polypeptide chain using a peptide bond
• the polypeptide chain grows until a stop codon is reached
• the polypeptide chain and mRNA are then released by the ribosome

Question 24

How does tRNA know which amino acid to attach?

Answer 24

each tRNA molecule carries just one kind of amino acid

Question 25

How do the three types of RNA come together during translation?

Answer 25

mRNA: carried coded message tRNA:delivers amino acids that are called for by the codons and enables ribosome to read the mRNA rRNA: hold ribosomal proteins in place, locates the start codon, and bonds amino acids together

Question 26

How do proteins affect the traits/genes in organisms?

Answer 26

- Many proteins are enzymes that catalyze/regulate reactions - Enzymes can control pigments in organisms - proteins can regulate growth

Question 27

All living things produce proteins in this way?

Answer 27

3 bases at a time

Question 28

Does a single strand from the double helix contain all of the information needed to reconstruct the other half of the strand?

Answer 28

Yes, it is the mechanism of base pairing. | The strands are complimentary, each strand can be used to make the other strand.

Question 29

What is replication and what part of the cell cycle does this occur in?

Answer 29

Duplication of DNA & S phase = synthesis

Question 30

Prokaryotic DNA replication?

Answer 30

Regulatory proteins bind to a single starting point, replication proceeds in both directions until the entire chromosome is copied.

Question 31

Eukaryotic DNA replication?

Answer 31

Replication begins at many different places along the length of a chromosome. Replication proceeds in both directions until a complete set of chromosomes is produced

Question 32

What if DNA ploymerase misses a mistake?

Answer 32

Damaged regions are replicated and It may alter certain genes. Can have serious consequences such as Cancer and Huntington's disease

Question 33

Polyploidy

Answer 33

Extra sets of chromosomes larger and stronger typically occurs in Fruits & Fish

Question 34

How do mutations occur?

Answer 34

Cell inserts the wrong base or even skips a base as DNA is made. This can result in 2 types of mutations: Gene mutations- Mutations in a single gene Chromosomal mutations- changes in a whole chromosome

Question 35

What is a point mutation?

Answer 35

``` Changes in one or few nucleotides occurs at a single point in replication there are three types of point mutations: Substitution Insertions & Deletions ```

Question 36

Substitution?

Answer 36

1 base is changed affects 1 amino acid almost no overall affect

Question 37

Insertions?

Answer 37

one base is inserted | insertions and deletions are known as frameshift mutations

Question 38

Deletions?

Answer 38

1 base is removed (insertions and deletions are known as frameshift mutations)

Question 39

Frameshift mutations?

Answer 39

Can have a dramatic affect. Causes the entire sequence of codons to be shifted. Can change every amino acid that follows the point of mutation, and can also alter mutations to the point that it will not function.

Question 40

Chromosomal mutations?

Answer 40

``` Can change the location of genes on a chromosome Four types: 1.Deletion 2.Duplication 3.Inversion 4.Translocation ```

Question 41

Deletion?

Answer 41

loss of all or part of chromosome

Question 42

Duplication?

Answer 42

Produces an extra copy of all or part of chromosome

Question 43

Inversion?

Answer 43

Reverses the direction of parts of the chromosome

Question 44

Translocation?

Answer 44

When a part of a chromosome breaks off and attaches to a different chromosome

Question 45

How do mutations affect genes?

Answer 45

Some have little to no affect. Some are beneficial. Some are harmful.

Question 46

What are Mutagens?

Answer 46

Chemical or physical agents in the environment Pesticides, smoke, pollutants Radiation, (x-rays,UV)

Question 47

Harmful Mutations

Answer 47

Those that change protein and cell activity genetic disorders cancer sickle cell

Question 48

Helpful Affects

Answer 48

Can produce proteins with new or altered functions Can be helpful in different/changing environments resisting pesticides/herbicides resisting bone fractures and HIV