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Biology > Test 2 Semester 2 > Flashcards

Test 2 Semester 2 Flashcards

1
Q

What roles do telomeres play in DNA replication?

A

telomeres prevent replication from skipping the ends of the DNA sequence

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2
Q

What differences are there between DNA &and RNA

A

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

and instead of thymine it has Uracil

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3
Q

What are the 4 functions of DNA polymerase?

A

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

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4
Q

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

A

Thynine – Adenine
Guanine – Cytosine
Adenine – Uracil

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5
Q

What is transcription?

A

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

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6
Q

What is Translation?

A

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

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7
Q

What causes translation to stop?

A

stop codons

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8
Q

Give at least one example of a stop codon:

A

UGA
UAA
UAG

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9
Q

What are mutations?

A

Heritable changes in genetic information

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10
Q

What does a cell use to decode DNA?

A

RNA

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11
Q

What does RNA do?

A

Protein synthesis

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12
Q

What is the first step in making proteins from DNA?

A

A cell must copy part of a DNA molecule into RNA

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13
Q

What is the second step in making proteins from DNA?

A

RNA uses the instructions to produce proteins

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14
Q

What are the three main types of RNA?

A 
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
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15
Q

How does the cell make RNA?

A

Transcription

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16
Q

Where is RNA made in prokaryotes and eukaryotes?

A

Prokaryotes: cytoplasm
Eukaryotes: Nucleus

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17
Q

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

A

Called pre-mRNA

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

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18
Q

What makes up proteins?

A

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

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19
Q

How many different 3 base codons are possible?

A

64

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20
Q

How are genetic messages decoded?

A

base sequence is transcribed from DNA to RNA

the transcribed info contains the code for making proteins

21
Q

What is an example of a start codon?

A

AUG

22
Q

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

A

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

23
Q

Steps of Translation:

A
  • 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
24
Q

How does tRNA know which amino acid to attach?

A

each tRNA molecule carries just one kind of amino acid

25
Q

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

A

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

26
Q

How do proteins affect the traits/genes in organisms?

A
  • Many proteins are enzymes that catalyze/regulate reactions
  • Enzymes can control pigments in organisms
  • proteins can regulate growth
27
Q

All living things produce proteins in this way?

A

3 bases at a time

28
Q

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

A

Yes, it is the mechanism of base pairing.

The strands are complimentary, each strand can be used to make the other strand.

29
Q

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

A

Duplication of DNA & S phase = synthesis

30
Q

Prokaryotic DNA replication?

A

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

31
Q

Eukaryotic DNA replication?

A

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

32
Q

What if DNA ploymerase misses a mistake?

A

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

33
Q

Polyploidy

A

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

34
Q

How do mutations occur?

A

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

35
Q

What is a point mutation?

A 
Changes in one or few nucleotides 
occurs at a single point in replication
there are three types of point mutations:
Substitution
Insertions 
& Deletions
36
Q

Substitution?

A

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

37
Q

Insertions?

A

one base is inserted

insertions and deletions are known as frameshift mutations

38
Q

Deletions?

A

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

39
Q

Frameshift mutations?

A

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.

40
Q

Chromosomal mutations?

A 
Can change the location of genes on a chromosome
Four types:
1.Deletion
2.Duplication
3.Inversion
4.Translocation
41
Q

Deletion?

A

loss of all or part of chromosome

42
Q

Duplication?

A

Produces an extra copy of all or part of chromosome

43
Q

Inversion?

A

Reverses the direction of parts of the chromosome

44
Q

Translocation?

A

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

45
Q

How do mutations affect genes?

A

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

46
Q

What are Mutagens?

A

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

47
Q

Harmful Mutations

A

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

48
Q

Helpful Affects

A

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

Biology (5 decks)

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