BIOLOGY > KEY TERMS > Flashcards

KEY TERMS Flashcards

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1
Q

What is ribose?

A

A five-carbon sugar found in RNA, important for forming the backbone of nucleic acids

Ribose has one more hydroxyl group than deoxyribose.

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2
Q

What is deoxyribose?

A

A five-carbon sugar found in DNA, missing one oxygen atom compared to ribose

This makes DNA more stable.

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3
Q

Define phosphate group.

A

A molecule consisting of a phosphorus atom bonded to four oxygen atoms, part of the backbone of nucleic acids

It links nucleotides together.

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4
Q

What is a nitrogenous base?

A

A nitrogen-containing molecule that forms the steps of the DNA ladder or RNA helix

Includes adenine, thymine, cytosine, guanine, and uracil.

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5
Q

Define nucleic acid.

A

A polymer composed of nucleotide monomers, such as DNA and RNA, that store and transfer genetic information

Nucleic acids are essential for genetic functions.

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6
Q

What is a nucleotide?

A

The basic building block of nucleic acids, composed of a sugar, a phosphate group, and a nitrogenous base

Nucleotides are the monomers that make up nucleic acids.

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7
Q

What is adenine?

A

A purine nitrogenous base in DNA and RNA that pairs with thymine in DNA and uracil in RNA

Adenine is one of the key components of nucleic acids.

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8
Q

What is thymine?

A

A pyrimidine nitrogenous base in DNA that pairs with adenine

Thymine is not found in RNA.

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9
Q

What is guanine?

A

A purine nitrogenous base in DNA and RNA that pairs with cytosine

Guanine is essential for the structure of nucleic acids.

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10
Q

What is cytosine?

A

A pyrimidine nitrogenous base in DNA and RNA that pairs with guanine

Cytosine is one of the fundamental building blocks of nucleic acids.

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11
Q

Define pyrimidines.

A

A class of nitrogenous bases with a single-ring structure, including cytosine, thymine (in DNA), and uracil (in RNA)

Pyrimidines are one of the two categories of nitrogenous bases.

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12
Q

Define purines.

A

A class of nitrogenous bases with a double-ring structure, including adenine and guanine

Purines are essential components of nucleic acids.

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13
Q

What are phosphodiester bonds?

A

Covalent bonds that link the sugar-phosphate backbone of nucleic acids, joining nucleotides together

These bonds are crucial for the structural integrity of nucleic acids.

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14
Q

What are hydrogen bonds?

A

Weak bonds between complementary nitrogenous bases (e.g., adenine-thymine, guanine-cytosine) that stabilize the double-stranded structure of DNA

Hydrogen bonds are essential for the base pairing in DNA.

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15
Q

What does antiparallel mean in the context of DNA?

A

Describes the opposite orientation of the two strands of DNA, with one strand running 5’ to 3’ and the other running 3’ to 5’

This orientation is critical for DNA replication and function.

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16
Q

Define chromosome.

A

A long, threadlike structure made of DNA and proteins that carries genetic information in cells

Chromosomes are essential for cell division and genetic inheritance.

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17
Q

What are plasmids?

A

Small, circular DNA molecules found in bacteria and some other organisms, often carrying genes that provide an advantage, like antibiotic resistance

Plasmids play a significant role in genetic engineering and biotechnology.

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18
Q

What is a histone?

A

Proteins around which DNA is wrapped in eukaryotic cells to form nucleosomes, helping to compact and organize the DNA

Histones are crucial for the regulation of gene expression.

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19
Q

What are nucleosomes?

A

Structural units of chromatin, consisting of DNA wrapped around histone proteins

Contributing to the packaging of DNA.

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20
Q

Define genome.

A

The complete set of genetic material (DNA or RNA) in an organism, including all its genes

Represents the total genetic information of an organism.

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21
Q

What is a gene?

A

A specific sequence of DNA that codes for a protein or RNA molecule, influencing an organism’s traits

Fundamental unit of heredity.

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22
Q

What are non-coding regions?

A

Sections of DNA that do not code for proteins but may have regulatory or structural roles

Important for gene regulation.

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23
Q

Define alleles.

A

Different forms or variants of a gene that can produce variations in traits

Contribute to genetic diversity.

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24
Q

What is complementary base-pairing?

A

The specific pairing of nitrogenous bases in DNA (adenine with thymine, guanine with cytosine) or in RNA (adenine with uracil, guanine with cytosine)

Ensures accurate DNA replication and transcription.

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25
What is an **exon**?
The coding regions of a gene that are transcribed into mRNA and translated into protein ## Footnote Essential for protein synthesis.
26
Define **genetic code**.
The set of rules by which information in DNA or RNA is translated into proteins, using codons that specify particular amino acids ## Footnote Fundamental to the process of translation.
27
What is an **intron**?
Non-coding regions of a gene that are transcribed into mRNA but are spliced out before translation into protein ## Footnote Play a role in gene regulation.
28
What is an **operator**?
A DNA sequence in prokaryotic operons that acts as a binding site for repressor proteins to control the transcription of adjacent genes ## Footnote Key component in gene regulation.
29
Define **operon**.
A group of genes in prokaryotes that are regulated together, typically involved in the same metabolic pathway ## Footnote Allows coordinated expression of related genes.
30
What is a **poly-A tail**?
A string of adenine nucleotides added to the 3' end of eukaryotic mRNA, important for stability, export, and translation ## Footnote Enhances mRNA longevity.
31
What is a **promoter region**?
A sequence of DNA located near the beginning of a gene that is recognized by RNA polymerase to initiate transcription ## Footnote Crucial for gene expression.
32
Define **regulatory gene**.
A gene that codes for a protein (such as a repressor or activator) that regulates the expression of other genes ## Footnote Plays a role in controlling gene activity.
33
What is a **structural gene**?
A gene that codes for a protein or RNA that has a specific function, as opposed to regulatory genes ## Footnote Essential for producing functional products.
34
What is **alternative splicing**?
A process where a single gene can produce multiple protein variants by including or excluding different exons during mRNA processing ## Footnote Increases protein diversity.
35
Define **base pair**.
Two complementary nitrogenous bases in DNA or RNA that are bonded together, such as adenine pairing with thymine (or uracil in RNA) and guanine with cytosine ## Footnote Fundamental unit of the DNA structure.
36
What does **Deoxyribonucleic acid (DNA)** carry?
Genetic instructions used in growth, development, and reproduction ## Footnote DNA is composed of two strands forming a double helix.
37
What is the function of **DNA polymerase**?
Catalyzes the synthesis of a new DNA strand by adding nucleotides ## Footnote This occurs during DNA replication.
38
Define **gene expression**.
The process by which the information encoded in a gene is used to produce a functional product ## Footnote Typically a protein or RNA.
39
What is **Messenger RNA (mRNA)**?
RNA molecule that carries genetic information from DNA to the ribosome ## Footnote It is used to synthesize proteins.
40
What is the **non-template strand** of DNA?
The strand not used as a template during transcription ## Footnote It is identical to the mRNA sequence (except for thymine being replaced by uracil).
41
What is the purpose of a **Poly-A tail**?
Aids in stability and translation of eukaryotic mRNA ## Footnote It is a string of adenine nucleotides added to the 3' end after transcription.
42
What is **pre-mRNA**?
The initial, unprocessed RNA transcript synthesized from a gene ## Footnote It includes both exons and introns before splicing.
43
Define **Ribonucleic acid (RNA)**.
A single-stranded nucleic acid involved in protein synthesis ## Footnote It carries genetic information from DNA to ribosomes.
44
What does **RNA polymerase** do?
Synthesizes RNA by transcribing a DNA template ## Footnote This occurs during the process of transcription.
45
What is a **template** in the context of nucleic acids?
A strand of DNA or RNA that serves as a guide for synthesizing a complementary strand ## Footnote Used during replication or transcription.
46
What is the **template strand**?
The DNA strand read by RNA polymerase during transcription ## Footnote It creates a complementary RNA molecule.
47
What does it mean to **transcribe**?
The process of synthesizing RNA from a DNA template ## Footnote The genetic information in DNA is copied into RNA.
48
Define **transcription**.
The process of copying a segment of DNA into RNA by RNA polymerase ## Footnote This forms mRNA used in protein synthesis.
49
What are **transcription factors**?
Proteins that bind to specific DNA sequences to regulate transcription ## Footnote They can aid or block RNA polymerase activity.
50
What is **alternative splicing**?
A process where different combinations of exons are joined together ## Footnote Produces multiple mRNA variants from a single gene.
51
What are **amino acids**?
Organic compounds that combine to form proteins ## Footnote Each has a specific side chain that determines its properties.
52
What is an **anticodon**?
A three-nucleotide sequence in tRNA complementary to a codon in mRNA ## Footnote Ensures proper amino acid incorporation during translation.
53
Define **base pair**.
Two complementary nucleotides held together by hydrogen bonds ## Footnote Examples include adenine paired with thymine (or uracil in RNA) and guanine paired with cytosine.
54
What is a **Codon**?
A three-nucleotide sequence in mRNA that specifies a particular amino acid during protein synthesis ## Footnote Codons are essential for translating genetic information into proteins.
55
What does **Degenerate** refer to in genetics?
The redundancy of the genetic code, where multiple codons can specify the same amino acid ## Footnote This feature allows for some mutations to be silent, not affecting the protein produced.
56
Define **Functional proteins**.
Proteins that have a specific biological function, such as enzymes, antibodies, or structural components ## Footnote Functional proteins are crucial for various biological processes.
57
What is a **Peptide bond**?
A covalent bond formed between the carboxyl group of one amino acid and the amino group of another, linking amino acids in a protein ## Footnote Peptide bonds are fundamental to protein structure.
58
What is a **Protein**?
Large, complex molecules made up of amino acids that perform a variety of functions, including catalysis, structure, and regulation in living organisms ## Footnote Proteins are essential for life and perform numerous roles in biological systems.
59
What is **Ribosomal RNA (rRNA)**?
RNA molecules that are a key component of ribosomes and are involved in protein synthesis by facilitating the translation of mRNA into amino acid sequences ## Footnote rRNA plays a critical role in the assembly of ribosomes.
60
What is a **Ribosome**?
A molecular machine composed of rRNA and proteins, responsible for synthesizing proteins by translating mRNA into polypeptide chains ## Footnote Ribosomes are essential for protein synthesis in all living cells.
61
Define **Subunit** in the context of ribosomes.
A smaller, individual protein or RNA component of a larger complex, such as the large and small subunits of a ribosome ## Footnote Subunits come together to form functional ribosomes.
62
What is the role of **Transfer RNA (tRNA)**?
A type of RNA that carries amino acids to the ribosome during translation and matches them with the appropriate codons in the mRNA ## Footnote tRNA is crucial for the accurate translation of mRNA into proteins.
63
What is **Translation**?
The process by which a ribosome reads an mRNA molecule and synthesizes a corresponding polypeptide (protein) chain ## Footnote Translation is a key step in gene expression.
64
What is **Attenuation**?
A regulatory mechanism in bacterial gene expression where transcription is prematurely terminated, often in response to the concentration of certain metabolites ## Footnote Attenuation helps bacteria adapt to changing environments.
65
Define the **Genetic code**.
The set of rules that defines how sequences of DNA or RNA are translated into amino acids to form proteins ## Footnote The genetic code is universal among most organisms.
66
What is a **Regulatory gene**?
A gene that produces proteins (like repressors or activators) that regulate the expression of other genes ## Footnote Regulatory genes play a crucial role in controlling gene expression.
67
What is a **Repressor protein**?
A protein that binds to DNA to inhibit the transcription of a gene, thereby preventing gene expression ## Footnote Repressor proteins are key players in gene regulation.
68
Define **Substrate** in enzymatic reactions.
A molecule upon which an enzyme acts to catalyze a biochemical reaction ## Footnote The interaction between an enzyme and its substrate is critical for catalysis.
69
What does it mean to **Transcribe**?
To copy a segment of DNA into RNA, typically referring to the creation of mRNA from a gene's DNA template ## Footnote Transcription is the first step in gene expression.
70
What is **Transcription**?
The process by which RNA is synthesized from a DNA template, resulting in mRNA, which carries genetic information for protein synthesis ## Footnote Transcription is essential for producing mRNA from DNA.
71
What is an **𝛼-helix (alpha helix)**?
A common secondary structure of proteins, where the polypeptide chain coils into a right-handed spiral stabilized by hydrogen bonds ## Footnote The alpha helix is a fundamental structural motif in proteins.
72
What is a **𝛽-pleated sheet (beta pleated sheet)**?
A secondary protein structure formed by hydrogen bonding between parallel or antiparallel strands of polypeptide chains, creating a sheet-like structure ## Footnote Beta pleated sheets contribute to the overall stability of protein structures.
73
Define **hydrophilic**.
Molecules or parts of molecules that are attracted to water, typically polar and capable of forming hydrogen bonds with water molecules. ## Footnote Hydrophilic substances interact well with water.
74
Define **hydrophobic**.
Molecules or parts of molecules that repel water, typically nonpolar and unable to form hydrogen bonds with water. ## Footnote Hydrophobic substances do not mix well with water.
75
What is the **primary structure** of a protein?
The sequence of amino acids in a polypeptide chain, determining the protein’s specific structure and function. ## Footnote The primary structure is crucial for the protein's overall shape.
76
Define **quaternary structure**.
The arrangement of multiple polypeptide chains (subunits) in a protein, resulting in a functional multi-subunit complex. ## Footnote Quaternary structure is important for the functionality of many proteins.
77
What is a **random coil**?
A disordered, flexible region of a polypeptide chain that lacks a regular secondary structure, often involved in protein flexibility or interaction. ## Footnote Random coils can play a role in protein dynamics.
78
Define **secondary structure**.
The localized folding of a polypeptide chain into structures like alpha helices or beta sheets, stabilized by hydrogen bonds. ## Footnote Secondary structures are key for the overall shape of proteins.
79
What is a **subunit**?
A smaller, individual component of a larger molecular complex, such as the protein subunits of a ribosome or enzyme. ## Footnote Subunits can combine to form larger functional complexes.
80
Define **tertiary structure**.
The three-dimensional shape of a protein formed by the folding of its secondary structures, stabilized by various interactions like hydrogen bonds and hydrophobic forces. ## Footnote Tertiary structure is critical for the protein's function.
81
What is a **catalyst**?
A substance that accelerates the rate of a chemical reaction without being consumed, often referring to enzymes in biological systems. ## Footnote Catalysts lower the activation energy of reactions.
82
Define **cellular signalling**.
The process by which cells communicate with each other through signaling molecules, triggering specific responses that regulate cell functions. ## Footnote Cellular signalling is essential for maintaining homeostasis.
83
What are **cell surface receptors**?
Proteins located on the surface of cells that bind to signaling molecules, initiating intracellular signaling pathways. ## Footnote These receptors are crucial for cell communication.
84
Define **defence** in biological terms.
The biological mechanisms used by organisms to protect against harmful agents like pathogens, toxins, or foreign invaders. ## Footnote Defence mechanisms include immune responses.
85
What is **motility**?
The ability of cells or organisms to move actively, often through structures like flagella or cilia, enabling them to respond to environmental stimuli. ## Footnote Motility is important for survival and adaptation.
86
Define **proteome**.
The entire set of proteins expressed by a genome, cell, or organism at a given time, reflecting its functional capabilities. ## Footnote The proteome can change in response to environmental conditions.
87
What is **proteomics**?
The large-scale study of proteins, their functions, interactions, and modifications within a biological system. ## Footnote Proteomics helps in understanding cellular processes.
88
Define **structural** proteins.
Referring to proteins or components that provide support, shape, and organization to cells or organisms, such as collagen or actin. ## Footnote Structural proteins are vital for maintaining cell integrity.
89
What does **transport** refer to in biological systems?
The movement of substances, such as ions, nutrients, or proteins, across membranes or within cells, often facilitated by transport proteins or channels. ## Footnote Transport is essential for cellular function and homeostasis.
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