Biology Collin Custom Sets > Unit 6 > Flashcards

Unit 6 Flashcards

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1
Q

Define gene expression.

A

The process by which information from a gene is used to synthesize a functional gene product, usually a protein.

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2
Q

True or false: Transcription occurs in the nucleus.

A

TRUE

Transcription is the first step in gene expression, where DNA is converted to RNA.

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3
Q

Fill in the blank: RNA polymerase synthesizes _______ during transcription.

A

RNA

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4
Q

What is the role of ribosomes?

A

Ribosomes are cellular structures that synthesize proteins by translating messenger RNA.

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5
Q

Define mutation.

A

A change in the nucleotide sequence of an organism’s DNA, which can affect protein function.

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6
Q

True or false: Point mutations can be silent, missense, or nonsense.

A

TRUE

Point mutations involve a change in a single nucleotide.

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7
Q

What is mRNA?

A

Messenger RNA is a type of RNA that carries genetic information from DNA to the ribosome.

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8
Q

Fill in the blank: The start codon is _______.

A

AUG

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9
Q

Define operon.

A

A cluster of genes under the control of a single promoter, functioning together in prokaryotic cells.

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10
Q

What is the function of tRNA?

A

Transfer RNA transports amino acids to the ribosome during protein synthesis.

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11
Q

True or false: Eukaryotic cells have introns and exons.

A

TRUE

Introns are non-coding sequences, while exons are coding sequences in eukaryotic genes.

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12
Q

What is splicing?

A

The process of removing introns and joining exons in pre-mRNA to produce mature mRNA.

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13
Q

Fill in the blank: Translation occurs in the _______.

A

cytoplasm

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14
Q

Define chromatin.

A

A complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.

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15
Q

What is a promoter?

A

A DNA sequence that initiates transcription of a particular gene.

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16
Q

True or false: Enhancers increase the likelihood of transcription.

A

TRUE

Enhancers are regulatory DNA sequences that can be located far from the gene they regulate.

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17
Q

What is the role of transcription factors?

A

Proteins that help regulate the transcription of specific genes by binding to nearby DNA.

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18
Q

Fill in the blank: DNA replication is semi-_______.

A

conservative

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19
Q

Define telomeres.

A

The protective caps at the ends of eukaryotic chromosomes that prevent degradation.

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20
Q

What is polyadenylation?

A

The addition of a poly-A tail to mRNA, which aids in export from the nucleus and stability.

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21
Q

True or false: Ribozymes are RNA molecules that can catalyze chemical reactions.

A

TRUE

Ribozymes play a role in RNA processing and protein synthesis.

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22
Q

What is epigenetics?

A

The study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence.

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23
Q

Fill in the blank: Histone modification can affect _______ structure.

A

chromatin

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24
Q

Define genetic recombination.

A

The process by which genetic material is physically mixed during meiosis, leading to genetic diversity.

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25
What is the role of **DNA ligase**?
An enzyme that joins DNA fragments together during replication and repair.
26
True or false: **Transposons** are mobile genetic elements.
TRUE ## Footnote Transposons can move within and between genomes, affecting gene function.
27
What is **PCR**?
Polymerase Chain Reaction is a technique used to amplify specific DNA sequences.
28
Fill in the blank: **Gel electrophoresis** separates DNA fragments by _______.
size
29
Define **genome**.
The complete set of genes or genetic material present in a cell or organism.
30
Fill in the blank: **CRISPR** is a tool for _______ editing.
gene
31
Define **allele**.
Different forms of a gene that arise by mutation and are found at the same place on a chromosome.
32
What is **phenotype**?
The observable physical or biochemical characteristics of an organism, determined by its genotype.
33
True or false: **Genotype** refers to the physical expression of traits.
FALSE ## Footnote Genotype refers to the genetic makeup of an organism.
34
What is **natural selection**?
The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
35
Fill in the blank: **Genetic drift** is a mechanism of _______ change.
evolution
36
Define **speciation**.
The formation of new and distinct species in the course of evolution.
37
What is **biodiversity**?
The variety of life in the world or in a particular habitat or ecosystem.
38
True or false: **Extinction** is a natural part of evolution.
TRUE ## Footnote Extinction can result from environmental changes, competition, and other factors.
39
Nucleotide
Made of Sugar - deoxyribose, Phosphate group, Nitrogen - # of carbons determines how they bond
40
DNA
Double Helix • Sides are anti-parallel • A - T, C - G • Pyrimidines - Cytosine - All pyrimidines have y's in the spelling • A - T H: Bonds = hydrogen bonds • C - G 3 H: bonds
41
DNA Replication - Step
• unwind separate DNA double Helix - Here enzyme halts DNA helix • Stabilizer by • Single-Stranded binding Proteins
42
Step
• Build daughter DNA Strand - DNA Polymerase - building enzyme - add new complementary bases
43
Energy of Replication
• Nucleotides arrive as nucleosides - DNA hates methyl • P-P-P 2 energy for Bonding
44
What is the **direction** in which a DNA strand grows?
5' to 3' ## Footnote DNA synthesis occurs by adding nucleotides to the 3' end of the growing strand.
45
What are the two types of strands involved in DNA replication?
* Leading Strand * Lagging Strand ## Footnote The leading strand is synthesized continuously, while the lagging strand is synthesized in fragments.
46
What enzyme is responsible for starting DNA synthesis?
Primase ## Footnote Primase builds RNA primers that serve as starting points for DNA polymerase.
47
What is the role of **DNA Polymerase**?
* Replaces RNA primers with DNA nucleotides * Can only build onto the 3' end of an existing DNA strand ## Footnote DNA polymerase is essential for DNA replication.
48
What happens to chromosomes during DNA replication?
They get shorter with each replication ## Footnote This shortening limits the number of cell divisions.
49
Fill in the blank: **RNA primers** are built by _______.
Primase ## Footnote RNA primers are essential for initiating DNA synthesis.
50
True or false: DNA polymerase can synthesize DNA without a starting point.
FALSE ## Footnote DNA polymerase requires an existing strand to build onto.
51
What is the role of **telomerase** in relation to **telomeres**?
Telomerase extends telomeres and can add RNA bases at the 5' end ## Footnote Telomerase activity varies in different cell types, being higher in certain cells.
52
What is the significance of **telomere repetition**?
Telomere repetition limits cell division ## Footnote This limitation is crucial for cellular aging and stability.
53
True or false: **Telomerase** activity is the same in all cell types.
FALSE ## Footnote Different levels of activity are observed in various cell types.
54
Fill in the blank: **Telomerase** can add _______ bases at the 5' end.
RNA ## Footnote This addition is important for the maintenance of telomeres.
55
What is the primary focus of **gene regulation** in eukaryotes?
Regulate body growth and development ## Footnote Gene regulation involves long-term processes and the turning on and off of large numbers of genes.
56
What are the **points of control** in gene expression?
Control can occur at any step in the pathway from gene to functional protein ## Footnote This includes various mechanisms that influence gene expression.
57
What does **DNA packing** involve?
* Packing double helix into nucleosomes * Chromatin supercoiling into divisions * Degree of packing regulates transcription ## Footnote Tightly packed DNA (heterochromatin) prevents transcription, while loosely packed DNA (euchromatin) allows it.
58
What is the effect of **histone acetylation** on gene expression?
Promotes transcription ## Footnote Histone acetylation involves the attachment of acetyl groups, which can alter the structure of chromatin.
59
True or false: **Heterochromatin** is loosely packed DNA that allows for transcription.
FALSE ## Footnote Heterochromatin is tightly packed and generally not accessible for transcription.
60
What is the role of **euchromatin** in gene expression?
Loosely packed DNA that allows for transcription ## Footnote Euchromatin is associated with active gene expression.
61
unwinds dru
canses a -conformational change in histine proteins-
62
DNA more loosely wrapped
arrass histore
63
enables transcription
genes turned on
64
UNt methylation
Blocks transcription factors
65
No transcription
→ genes turned off
66
attachment of methyl group to
atosine ov to histore protein
67
nearly permanent inactivation of
genes
68
Transcription initiation
COnTIO reGiONS ON ONA
69
Promoter
→ nearby Control Sequence on ANA
70
Binding Of RNA polymerase and
tinsription factors
71
"base" late of transcription.
enhancer
72
distant Control Sequences on DNA
onang ot activator proteins
73
"enhances" fate
Chigh level) O+ transcription
74
activators
prompter
75
gen
ONA
76
TATA
enhancers
77
RNA
paymerase
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