Bio Chapter 10

Front 1

Viruses

Back 1

invaders that sabotage our
cells

Front 2

Viruses are____________ which
have genetic material surrounded
by a __________ and, in some
cases, a membranous envelope

Back 2

nucleic acids
protein coat

Front 3

Viral proteins bind to ________
on a host’s target cell

Back 3

receptors

Front 4

It is the ____ that provides most
of the tools and raw materials
needed to duplicate the virus

Back 4

host

Front 5

Once in the body, herpesvirus
travels until it finds a suitable
_______, it is recognized when
protein molecules on the outside
of the virus fit into protein
receptor molecules on the
surface of the cell. Not recognizing the threat, the cell takes
the virus in

Back 5

target cell

Front 6

Once inside the cell, the DNA of the herpesvirus enters the _____

Back 6

nucleus

Front 7

In the nuclei certain nerve cells, the viral
can remain dormant for long periods
until activated by ______

Back 7

“stress”

Front 8

When activated, the viral DNA ____ the
cell’s own molecules and organelles to
produce new copies of the virus

Back 8

hijacks

Front 9

The host cell is _______, and
newly replicated viruses are
released to continue the infection
and invade other health cells

Back 9

destroyed

Front 10

HIV is also able to remain
__________ in cells

Back 10

dormant (latent)

Front 11

For the HIV virus, this occurs
during the activation of _____
during the immune response,
so the insidious nature of the
HIV virus is that it destroys
cells at the very time they are
recruited to protect the body
from invaders

Back 11

T cells

Front 12

Bacteriophages

Back 12

viruses that infect bacterial
cells

Front 13

Phages were labeled with
_________ to detect
proteins or radioactive
phosphorus to detect DNA

Back 13

radioactive sulfur

Front 14

The monomer unit of DNA and
RNA is the nucleotide,
containing

Back 14

– Nitrogenous base
– 5-carbon sugar
– Phosphate group

Front 15

DNA and RNA are polymers called

Back 15

polynucleotides

Front 16

For the HIV virus, this occurs
during the activation of _____
during the immune response,
so the insidious nature of the
HIV virus is that it destroys
cells at the very time they are
recruited to protect the body
from invaders

Back 16

T cells

Front 17

RNA

Back 17

– Single strand not
double like DNA
– Has ribose sugar, not
deoxyribose like DNA
– Has the bases
adenine, cytosine, but
uracil instead of
thymine
– (In protein synthesis
there will be 3 types of
RNA: rRNA, mRNA,
tRNA)

Front 18

Bacteriophages

Back 18

viruses that infect bacterial
cells

Front 19

DNA is composed of two ____
chains joined together by ____
bonding between bases, twisted into a
____ shape

Back 19

polynucleotide
hydrogen
helical

Front 20

Phages were labeled with
_________ to detect
proteins or radioactive
phosphorus to detect DNA

Back 20

radioactive sulfur

Front 21

DNA replication follows a ______ model

Back 21

semiconservative
-Each strand is used as a pattern/template to produce a complementary
strand

Front 22

The monomer unit of DNA and
RNA is the nucleotide,
containing

Back 22

– Nitrogenous base
– 5-carbon sugar
– Phosphate group

Front 23

The two DNA strands separate/unwinds by enzyme...

Back 23

helicase

Front 24

DNA and RNA are polymers called

Back 24

polynucleotides

Front 25

DNA replication begins at the...

Back 25

origins of replication

Front 26

RNA

Back 26

– Single strand not
double like DNA
– Has ribose sugar, not
deoxyribose like DNA
– Has the bases
adenine, cytosine, but
uracil instead of
thymine
– (In protein synthesis
there will be 3 types of
RNA: rRNA, mRNA,
tRNA)

Front 27

DNA is composed of two ____
chains joined together by ____
bonding between bases, twisted into a
____ shape

Back 27

polynucleotide
hydrogen
helical

Front 28

DNA replication follows a ______ model

Back 28

semiconservative
-Each strand is used as a pattern/template to produce a complementary
strand

Front 29

The two DNA strands separate/unwinds by enzyme...

Back 29

helicase

Front 30

DNA replication begins at the...

Back 30

origins of replication

Front 31

DNA unwinds at the origin
to produce a ...

Back 31

“bubble”
– Replication proceeds in
both directions from the
origin
– Replication ends when
products from the bubbles
merge with each other

Front 32

DNA replication occurs in the _____ direction.

Back 32

5’ 3’

Front 33

Replication is _____ on
the 3’ 5’ template

Back 33

continuous

Front 34

Replication is ______
on the 5’ 3’ template.

Back 34

discontinuous
-forming short segments

Front 35

DNA polymerase

Back 35

adds
nucleotides to a growing
chain

Front 36

DNA ligase

Back 36

joins small
fragments into a
continuous chain

Front 37

Transcription

Back 37

the production of
RNA using DNA as a template

Front 38

transcription occurs
in the ______, and the resulting RNA (____) enters the cytoplasm

Back 38

nucleus
mRNA

Front 39

Translation

Back 39

production of
protein (amino acid chains), using the
sequence of nucleotides in RNA

Front 40

Each amino acid is specified
by a...

Back 40

codon
– 64 codons are possible
– Some amino acids
have more than one
possible codon

Front 41

Triplet

Back 41

Three nucleotides specify
one amino acid

Front 42

___ codons correspond to
amino acids

Back 42

61

Front 43

AUG codes for...

Back 43

methionine
and signals the start of
transcription

Front 44

__“stop” codons signal the
end of translation

Back 44

3
UAA
UGA
UAG

Front 45

Redundant

Back 45

More than one
codon for some amino acids

Front 46

Unambiguous

Back 46

Any codon
for one amino acid does not
code for any other amino acid

Front 47

Stages of transcription

Back 47

Initiation
Elongation
Termination

Front 48

Initiation

Back 48

RNA polymerase
binds to promoter* region at
beginning of a gene on
template strand

Front 49

Elongation:

Back 49

RNA polymerase
synthesizes a sequence of RNA
nucleotides along DNA template
strand; b. Bases in newly
synthesized RNA strand are
complementary to the DNA
template strand

Front 50

Termination

Back 50

RNA polymerase
reaches a terminator sequence
and detaches from the template
– A completed RNA (specifically
mRNA) is formed

Front 51

Messenger RNA (mRNA)

Back 51

contains
codons for protein sequences

Front 52

Eukaryotic mRNA has interrupting sequences called ____, separating
the coding regions called ___

Back 52

introns
exons

Front 53

Eukaryotic mRNA undergoes
processing before leaving the nucleus

Back 53

– Cap added to 5’ end: single
guanine nucleotide
– Tail added to 3’ end: Poly-A
tail of 50–250 adenines
– RNA splicing: removal of
introns and joining of exons to
produce a continuous coding
sequence

Front 54

Transfer RNA (tRNA)

Back 54

molecules
match an amino acid to its
corresponding mRNA codon
-An amino acid
attachment site allows
each tRNA to carry a
specific amino acid

Front 55

anticodon

Back 55

allows the
tRNA to bind to a specific
mRNA codon,
complementary in
sequence
– A pairs with U, G
pairs with C

Front 56

Translation occurs on the surface of
the ...

Back 56

ribosome

Front 57

Ribosomes have two
subunits:

Back 57

small and large
-Each subunit is composed of
ribosomal RNAs and proteins

Front 58

Ribosomal subunits come
together during ______. Ribosomes have binding
sites for ____

Back 58

translation
mRNA and tRNAs

Front 59

Elongation

Back 59

addition of amino acids
to the polypeptide chain

Front 60

Each cycle of elongation has three steps

Back 60

Codon recognition
Peptide bond formation
Translocation

Front 61

Codon recognition:

Back 61

tRNA
with its anticodons, binds to the
mRNA codons at the A site

Front 62

Peptide bond formation:

Back 62

joining of the new amino acid to
the chain
– Amino acids on the tRNA
at the P site are attached
by a covalent bond to the
amino acid on the tRNA
at the A site

Front 63

Translocation:

Back 63

tRNA is
released from the P site
and the ribosome moves
tRNA from the A site into
the P site

Front 64

Elongation continues until the
ribosome reaches a ....

Back 64

stop
codon

Front 65

mutation

Back 65

change in the nucleotide
sequence of DNA

Front 66

Base substitutions:

Back 66

replacement of one nucleotide
with another
– Effect depends on whether there is an amino acid change
that alters the function of the protein

Front 67

Deletions or insertions

Back 67

– Alter the reading frame of the mRNA, so that nucleotides
are grouped into different codons
– Lead to significant changes in amino acid sequence
downstream of mutation
– Cause a nonfunctional polypeptide to be produced

Front 68

Mutations can be

Back 68

– Spontaneous: due to errors in DNA replication or
recombination
– Induced by mutagens
– High-energy radiation
– Chemicals

Front 69

AIDS is caused by

Back 69

HIV, human
immunodeficiency virus

Front 70

HIV is a ______, containing

Back 70

retrovirus "backward"
– Two copies of its RNA genome
– Reverse transcriptase, an enzyme that produces
DNA from an RNA template

Front 71

HIV duplication

Back 71

– Reverse transcriptase uses RNA to produce one DNA strand
– Reverse transcriptase produces the complementary
DNA strand
– Viral DNA enters the nucleus and integrates into the
chromosome, becoming a provirus
– Provirus DNA is used to produce mRNA
– mRNA is translated to produce viral proteins
– Viral particles are assembled and leave the host cell

Front 72

Viroids:

Back 72

circular RNA molecules that infect plants
– Replicate within host cells without producing proteins
– Interfere with plant growth

Front 73

Prions

Back 73

infectious proteins that cause brain diseases
in animals
– Misfolded forms of normal brain proteins
– Convert normal protein to misfolded form