test 3 Flashcards
chapter 7-9
1
Q
What is Deoxyribonucleic Acid (DNA)?
A
Hereditary molecule passed from parents to offspring
2
Q
where is DNA found?
A
- Nucleus of eukaryotes
- Cytoplasm (nucleoid) of prokaryotes
3
Q
DNA is organized into discreet structures and consists of a single DNA molecule wrapped around proteins
A
Chromosome
4
Q
How is DNA Organized in Cell?
A
- Allows DNA to be compacted and organized in nucleus
- DNA from one of your cells would be ~ 6 feet long if you uncoiled each strand and placed them end to end
5
Q
Prokaryotes have
Eukaryotes have
A
Prokaryotes typically have 1 circular chromosome
Eukaryotes have multiple linear chromosomes
6
Q
Humans have how many chromosomes?
A
46 chromosomes and 23 pairs of chromosomes
7
Q
one chromosome from each pair is inherited from?
A
the mother and father
8
Q
the 23rd chromosome pair determines a person’s?
A
sex (which is called the sex chromosomes)
XX = female
XY = male
9
Q
What is DNA four nitrogenous bases
A
- Thymine (T)
- Adenine (A)
- Guanine (G)
- Cytosine (C)
9
Q
A DNA molecule is made up of
A
two strands of nucleotides
9
Q
What are the strands of nucleotides held together by
A
hydrogen bonds
9
Q
What is DNA structure?
A
Sugar (deoxyribose)
phosphate group
Nitrogenous base
10
Q
Two strands twist around
each other to form a
A
spiral-shaped double helix
11
Q
Sugars and phosphates forms the_____ and the Nitrogenous bases forms the ______
A
Form outside “backbone” and Form the internal “rungs” like steps on ladder
12
Q
Strands of nucleotides have
A
directionality
End-to-end chemical orientation of single strand of nucleic acid
* 5’ end (phosphate group) and 3’ end (sugar)
13
Q
The two strands of nucleotides are
A
antiparallel (run in opposite directions) to one another
14
Q
Nitrogenous bases form the hydrogen bonds that hold the two
strand together. What is the base pairing rule that the bonds use?
A
A pairs with T
* Two hydrogen bonds
C pairs with G
* Three hydrogen bonds
* Stronger pairing
15
Q
DNA is
A
Complementary
16
Q
a complete set of genetic instructions encoded in the DNA of an organism
A
A genome
17
Q
what is DNA replication
A
Copies of genome and therefore DNA need to made when
new cells are created
* Growth
* Tissue repair
* Reproduction
18
Q
The natural process by which cells make an identical copy of a DNA molecule
A
DNA Replication
19
Q
“DNA replication is semi-conservative.” What does this statement mean?
A
A double-stranded segment is replicated into two double-stranded segments, each one having one new strand and one old strand
20
Q
Replicating DNA requires
A
- Nucleotides
- Enzymes (catalyze chemical reactions)
21
Q
New DNA strand is synthesized by assembly of complementary nucleotides by
A
DNA polymerase
21
DNA polymerase works in
pairs each “reading” the
existing nucleotide strands (template strands) to create
two new strands
22
Begins when hydrogen bonds between bases are broken and the helix is unwound by
DNA helicase
23
Fragments bonded together (polymerized) by
ligase
23
Primase adds a ____ to start synthesis
RNA primer
24
At the end of replication, RNA primers are removed and replaced with DNA by a type of
DNA polymerase
25
Human DNA sequences are about ____ the same from to person to person (defines us a human)
99.9%
the 0.01% gives us our individuality
26
DNA contains
Coding sequences (genes)
* Sequences used to make proteins
* Extremely similar among individuals
Noncoding sequences
* Do not contain instructions for making protein
* Vary much more between individuals
27
are found in noncoding regions of DNA
* Sections of a chromosome in which DNA sequences are repeated
* STRs in the same places along chromosomes, but exact length of STR varies person to person
Short tandem repeats (STRs)
28
Creating a DNA profile involves
1. Collecting DNA
2. Amplifying STRs (PCR)
3. Separating STRs by size (gel electrophoresis)
4. Visualizing STRs and compare fragments
29
a laboratory technique used to replicate a specific DNA segment
Polymerase chain reaction (PCR)
30
Scientists add____, ______ & ______ to the DNA sample
Nucleotides, DNA polymerase & Primers
31
What happens during the PCR
the two nucleotide strands
separate via heat
* Breaks hydrogen bonds
* DNA polymerase pairs nucleotides beginning at primer
when sample is cooled
* Each strand of DNA used as
template for complementary
base pairing
32
Copies of STRs are separated using (Laboratory technique that
separates fragments of DNA by size and separates replicated STRs according to their length)
gel electrophoresis
33
Gel electrophoresis separates DNA
molecules by relative ________.
_______ fragments of DNA run toward the bottom of the gel
Size; Smaller
34
What type of bond occurs
between a partially positive
hydrogen and a partially
negative atom?
Hydrogen Bond
35
a sequence of DNA that contains the instructions to make a protein
gene
36
genes are generally separated by
noncoding regions of DNA
37
Specific position on chromosome where a particular gene is located
Locus (loci)
38
Gene Expression
Genes that are expressed when the cell uses the instructions in the DNA to make proteins
39
Genes are organized into what two parts
Regulatory sequence and coding sequence
40
Regulatory sequences Part of the gene that determines
1. Timing of gene expression
2. Amount of gene expression
3. Location of protein production (not all cells use same proteins)
41
Coding sequences Part of the gene that specifies the amino acid sequence of a protein Determines
1. Identity of protein
2. Shape of protein
3. Function of protein
42
how many amino acids are there
20
43
Each has a unique chemical
side group that may be
* Nonpolar
* Polar
* Charged (+ or -)
44
Amino acid chain folds into a 3-D protein based on sequence of amino acids due to
interactions between amino acids and surrounding molecules and interactions between amino acids and other amino acids
45
Hydrophobic (non-polar) amino acids
clump together in middle of protein
46
Hydrophilic amino acids
face outward or interact with one another
47
Polar molecules form
hydrogen bonds
48
Charged molecules form
ionic bonds
49
Nonpolar molecules form
hydrophobic interactions
50
Alternative versions of the same gene and Variation in nucleotide sequence
Alleles
51
can some variants be harmful
yes
52
Transcription is
the process of changing DNA into RNA
53
In Eukaryotes, transcription occurs in the___ whereas translation occurs in the____
nucleus and cytoplasm
54
Translation is
the process of RNA turning into protein
55
in prokaryotic cells transcription occurs in
the cytoplasm
56
what's the steps for transcription
1. RNA polymerase will bind to regulatory region
2. RNA polymerase will copy coding region of DNA (synthesize mRNA)
3. mRNA detaches from DNA
4. Finished mRNA leaves the nucleus through nuclear pores in nuclear envelope
57
cells produce molecules of
messenger RNA (mRNA)
58
RNA has
* Single Strand
* Ribose
* Cytosine (C)
* Guanine (G)
* Adenine (A)
* Uracil (U)
59
DNA has
* Double Strand
* Deoxyribose
* Cytosine (C)
* Guanine (G)
* Adenine (A)
* Thymine (T)
60
binds to the regulatory sequence of gene
RNA polymerase
61
The RNA polymerase moves along the______ DNA strand, “reading” the DNA sequence and synthesizing a complementary mRNA strand
template
62
DNA Polymerase
- DNA Replication
* Lays nucleotides in a 5’ to 3’ manner
* Reads both strands
3’ TGCA 5’
5’ ACGT 3’
63
RNA polymerase
* Transcription
* Lays nucleotides in a 5’ to 3’ manner
* Reads template (anti- sense) strand
3’ ACGT 5’
5’ UGCA 3’
64
As the mRNA strand is formed, it detaches from the DNA sequence and then
the DNA reforms its double-
stranded helix
65
After the mRNA molecule leaves the nucleus, the gene remains were
part of the chromosome in the nucleus where it can be used again for transcription
66
what's the steps for translation
1. mRNA associates with a ribosome
2. Ribosome reads the mRNA
3. tRNA brings the amino acid and attaches to the growing protein
4. Finished amino acid chain folds into the 3D protein
67
Transcribed mRNA associates with
a ribosome
68
One codon specifies where to start translation _____and some codons where to end_______
start codon ,stop codon
69
The ribosome reads the mRNA in
groups of three nucleotides called
a codon
70
mRNA codons specify particular amino acids according to the
universal genetic code
71
a type of RNA that carries an amino acid to the mRNA and ribosome
Transfer RNA (tRNA)
72
tRNAs use its _____ to
complimentary pair with the correct codon
anticodon
73
An organism that has been genetically altered by
humans
genetic engineering
73
refers to an organisms that carries one or more genes from a different species
Transgenic organisms
74
Research a gene’s function/Produce marketable products like medicine and
fibers
Transgenic animals
75
genetically engineered gene that contains portion of genes not naturally found together
Recombinant gene
76
a DNA molecule used to
deliver a recombinant
gene to a host cell
vector
77
round, flexible cells in the blood
that carry large amounts of oxygen
red blood cells
78
What Causes Sickle Cell Disease
a genetic mutation in the beta-globin gene
79
the protein portion of hemoglobin,
which carries oxygen in red blood cells
beta-globin
80
the change in the nucleotide sequence of DNA
mutation
81
An alternate version of the same gene
Mutated gene (allele)
82
Proteins are created through the process of
gene expression
83
Point mutations
Substituting one nucleotide for another
* Silent
* Missense
* Nonsense
84
Frameshift mutations
Change in the reading frame of a gene
* Insertion
* Deletion
85
Rearranged DNA mutations
Sections of DNA move
* Inversion
* Translocation
86
Results in a different amino acid sequence
Missense
87
No change in amino acid sequence
(due to genetic code being
redundant)
Silent
88
Introduces an early stop codon
Nonsense
89
Insert one or more nucleotides
Insertion
90
Deletes one or more nucleotides
Deletion
91
Moves segments of DNA from one
chromosome to another
Translocation
91
A group of DNA nucleotides are flipped to read in reverse order
Inversion
92
Germ-line mutations
Mutation occurs in sperm and egg cells (gametes)
* Passed from parent to child
* Present in all body cells of children
* Copied every time cells divide
93
Somatic cell mutations
* Non-germ cells (somatic)
* Not passed on to children
* Passed only to daughter cells (can still cause disease)
94
What Causes Mutations?
Errors in DNA replication
* Mutagens
94
mutations are
often undetectable
95
Chemical or physical agents that can generate a mutation in
DNA
mutagens
96
Substance that induces
unregulated cell division, thus cancer (Most are mutagens)
Carcinogens
97
mutagens can include
* Chemicals (pollution, pesticides, smoking, alcohol)
* Radiation (UV light and X-rays)
* Infectious Agents
* Free radicals produced by cells during metabolism such as aerobic respiration
98
Gene therapy encompasses many techniques like
* Viral vectors
* Gene editing
99
Produced by bacteria to defend against viruses and is Modified by scientist as a quick, easy, and cheap way to edit genes
* Can be used to change the sequence of a gene
CRISPR (clustered regularly interspaced short palindromic repeats)
100
Two main components of gene therapy: gene editing
* Enzyme that cuts DNA
* Small piece of RNA that serves
as a guide for the enzyme
