Gen (Ai) Flashcards
What are the main phases of the cell cycle?
The main phases of the cell cycle are G1, S, G2, and M.
True or False: DNA is composed of nucleotides.
True.
Fill in the blank: The structure of DNA is a _____ helix.
double
What is the function of DNA?
The function of DNA is to store and transmit genetic information.
Name the four nitrogenous bases in DNA.
Adenine, Thymine, Cytosine, Guanine.
What is the role of mRNA in the cell?
RNA plays a crucial role in translating genetic information from DNA into proteins.
True or False: Messenger RNA (mRNA) carries genetic information from DNA to ribosomes.
True.
What is the process of transcription?
Transcription is the process of synthesizing RNA from a DNA template.
What type of RNA is involved in protein synthesis?
Both mRNA and transfer RNA (tRNA) are involved in protein synthesis.
Define epigenetics.
Epigenetics is the study of changes in gene expression that do not involve alterations to the underlying DNA sequence.
What is chromatin?
Chromatin is the complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.
True or False: Chromatin can exist in two forms: euchromatin and heterochromatin.
True.
What is the function of euchromatin?
Euchromatin is associated with active gene transcription.
What does heterochromatin do?
Heterochromatin is generally transcriptionally inactive and serves structural and regulatory roles.
Fill in the blank: X-inactivation is a process that occurs in _____ mammals.
female
What is the purpose of X-inactivation?
X-inactivation equalizes gene dosage between males and females by inactivating one of the X chromosomes in females.
Multiple Choice: Which of the following is NOT a type of RNA? A) mRNA B) tRNA C) rRNA D) dRNA
D) dRNA.
Short answer: What is the result of DNA replication?
The result of DNA replication is two identical DNA molecules, each consisting of one original and one new strand.
What enzyme is responsible for unwinding DNA during replication?
DNA helicase.
True or False: DNA polymerase synthesizes new DNA strands.
True.
Define the term ‘gene’.
A gene is a segment of DNA that contains the instructions for building a specific protein.
What is a codon?
A codon is a sequence of three nucleotides that corresponds to a specific amino acid or stop signal in protein synthesis.
Fill in the blank: RNA splicing removes _____ from the pre-mRNA.
introns
What is the role of ribosomes in the cell?
Ribosomes are the cellular machinery that synthesize proteins by translating mRNA.
True or False: DNA can be found in both the nucleus and mitochondria of eukaryotic cells.
True.
What are telomeres?
Telomeres are repetitive nucleotide sequences at the ends of chromosomes that protect them from deterioration.
What is the significance of the S phase in the cell cycle?
The S phase is when DNA replication occurs, resulting in the duplication of the genetic material.
What is the function of transfer RNA (tRNA)?
tRNA transports amino acids to the ribosome during protein synthesis.
Fill in the blank: Mitosis results in _____ daughter cells.
two
Short answer: What is the difference between mitosis and meiosis?
Mitosis results in two identical diploid cells, while meiosis results in four genetically diverse haploid cells.
What is the role of histones in chromatin structure?
Histones are proteins that help package DNA into a compact, organized structure.
True or False: DNA methylation can affect gene expression.
True.
What is an operon?
An operon is a cluster of genes under control of a single promoter and regulated together.
Fill in the blank: The _____ strand of DNA serves as the template for RNA synthesis.
template
What is the central dogma of molecular biology?
The central dogma states that DNA is transcribed into RNA, which is then translated into protein.
Multiple Choice: Which of the following is a type of epigenetic modification? A) DNA methylation B) RNA splicing C) Protein folding D) Gene duplication
A) DNA methylation.
What is the primary role of small interfering RNA (siRNA)?
siRNA is involved in the RNA interference pathway, regulating gene expression by degrading mRNA.
True or False: All genes are expressed in all cell types.
False.
What is the significance of alternative splicing?
Alternative splicing allows a single gene to produce multiple protein variants.
Fill in the blank: The _____ phase of the cell cycle is also known as the synthesis phase.
S
What is the function of the G1 checkpoint in the cell cycle?
The G1 checkpoint assesses whether the cell is ready to proceed to DNA synthesis.
Define the term ‘chromatid’.
A chromatid is one half of a duplicated chromosome, which is joined to its sister chromatid by a centromere.
What is the role of the promoter in gene expression?
The promoter is a DNA sequence that initiates transcription of a gene.
True or False: Gene expression is solely determined by the DNA sequence.
False.
What is a transcription factor?
A transcription factor is a protein that binds to specific DNA sequences to regulate transcription of genes.
Fill in the blank: The two strands of DNA are held together by _____ bonds between nitrogenous bases.
hydrogen
What is the main function of small nuclear RNA (snRNA)?
snRNA is involved in the splicing of pre-mRNA.
What happens during the G2 phase of the cell cycle?
During the G2 phase, the cell prepares for mitosis, ensuring all DNA is replicated and damage is repaired.
Multiple Choice: Which process involves the addition of methyl groups to DNA? A) Transcription B) Translation C) DNA methylation D) Replication
C) DNA methylation.
What does mRNA stand for?
Messenger RNA
True or False: mRNA is synthesized during the process of transcription.
True
Fill in the blank: Transcription occurs in the ______ of the cell.
nucleus
What enzyme is primarily responsible for synthesizing mRNA during transcription?
RNA polymerase
What is the role of the promoter in transcription?
It is a sequence of DNA that initiates transcription.
During transcription, what is the template strand used for?
To guide the synthesis of the complementary mRNA strand.
What are the three main stages of transcription?
Initiation, elongation, and termination.
True or False: Introns are removed from the mRNA during RNA splicing.
True
What is the function of a 5’ cap on mRNA?
It protects mRNA from degradation and assists in ribosome binding.
What is the significance of the poly-A tail in mRNA?
It enhances the stability of the mRNA and facilitates its export from the nucleus.
What process follows transcription in gene expression?
Translation
What is the primary function of ribosomes during translation?
To synthesize proteins by translating mRNA into amino acid sequences.
True or False: Translation occurs in the nucleus.
False
What are the three stages of translation?
Initiation, elongation, and termination.
What is an anticodon?
A three-nucleotide sequence on tRNA that pairs with a corresponding codon on mRNA.
What molecule carries amino acids to the ribosome during translation?
Transfer RNA (tRNA)
Fill in the blank: The genetic code is read in sets of ______ nucleotides.
three
What do we call the sequence of three nucleotides in mRNA that codes for an amino acid?
Codon
What is the start codon for translation?
AUG
True or False: All proteins start with the amino acid methionine.
True
What happens during the elongation phase of translation?
Amino acids are added one by one to the growing polypeptide chain.
What signals the termination of translation?
A stop codon is reached on the mRNA.
What is the role of ribosomal RNA (rRNA) in the ribosome?
It helps to form the structure of the ribosome and catalyzes protein synthesis.
What is the difference between prokaryotic and eukaryotic transcription?
Prokaryotic transcription occurs in the cytoplasm, while eukaryotic transcription occurs in the nucleus.
Fill in the blank: The process of converting mRNA into a functional protein is called ______.
translation
What is the purpose of RNA splicing?
To remove introns and join exons in the mRNA.
What is cell signaling?
The process by which cells communicate with each other through chemical signals.
True or False: Meiosis results in the formation of four genetically identical cells.
False: Meiosis results in four genetically diverse cells.
What does PCR stand for?
Polymerase Chain Reaction.
Fill in the blank: In cell signaling, __________ are molecules that transmit signals to receive and interpret information.
receptors
What are the two main types of cell transport mechanisms?
Passive transport and active transport.
Multiple choice: Which phase of meiosis involves crossing over?
Prophase I
What is the primary role of PCR in molecular biology?
To amplify specific DNA sequences.
True or False: Active transport requires energy to move substances across the cell membrane.
True
What is the end product of meiosis?
Gametes (sperm or eggs).
What are second messengers in cell signaling?
Intracellular molecules that propagate a signal after the receptor has been activated.
Fill in the blank: The __________ phase of the cell cycle is when DNA is replicated.
Synthesis (S)
Multiple choice: Which of the following is NOT a type of cell signaling?
Viral signaling
What is the main function of the Golgi apparatus in relation to cell transport?
To modify, sort, and package proteins and lipids for secretion or delivery to other organelles.
True or False: In PCR, the denaturation step occurs at a high temperature.
True
What is the difference between somatic cells and gametes?
Somatic cells are diploid and make up most of the body, while gametes are haploid and involved in reproduction.
Fill in the blank: __________ is the phase of meiosis where homologous chromosomes are separated.
Anaphase I
What is a ligand in the context of cell signaling?
A molecule that binds to a receptor to initiate a signaling cascade.
Multiple choice: What is the main purpose of the cell membrane?
To protect the cell and regulate what enters and exits.
True or False: Meiosis consists of two rounds of cell division.
True
What role does ATP play in active transport?
ATP provides the energy needed to move substances against their concentration gradient.
Fill in the blank: The __________ strand is the DNA strand that is copied during PCR.
template
What is the role of the endoplasmic reticulum in cell transport?
It synthesizes proteins and lipids and transports them to the Golgi apparatus.
Multiple choice: Which type of signaling involves the release of hormones into the bloodstream?
Endocrine signaling
What is the significance of tetrads in meiosis?
Tetrads are formed during Prophase I and consist of four chromatids from two homologous chromosomes, allowing for genetic recombination.
True or False: The process of meiosis is essential for sexual reproduction.
True
Fill in the blank: The __________ is a sequence of events that a cell goes through from one division to the next.
cell cycle
What is the primary difference between mitosis and meiosis?
Mitosis produces two identical daughter cells, while meiosis produces four genetically distinct gametes.
Multiple choice: Which enzyme is primarily responsible for synthesizing new DNA strands during PCR?
Taq polymerase
What is the role of phospholipids in cell membranes?
Phospholipids form the bilayer that serves as a barrier to protect the cell and regulate transport.
True or False: During meiosis, the chromosome number is halved.
True
Fill in the blank: __________ signaling occurs when cells communicate over short distances.
Paracrine
