DNA VS RNA flashcards

All 30 cards

1. Card 1

   Define what a gene is according to molecular biology principles.

   A gene is a specific sequence of DNA that carries the instructions to encode for an RNA molecule. This RNA molecule may then be translated into a protein, serving as the fundamental unit of heredity passed from parents to offspring.

2. Card 2

   How do promoters contribute to the regulation of gene expression?

   Promoters are crucial regulatory elements because they serve as the specific binding site for RNA polymerase. This binding is the initial step that signals where transcription should begin, thereby controlling whether and when a gene is expressed.

3. Card 3

   Distinguish between the roles of co-activators and co-repressors in gene regulation.

   Co-activators are proteins that interact with enhancers to increase the rate of transcription, effectively boosting gene expression. In contrast, co-repressors decrease transcription by interacting with other regulatory proteins, thereby suppressing gene expression.

4. Card 4

   Explain the primary function of RNA polymerase during transcription.

   RNA polymerase is the enzyme responsible for catalyzing the synthesis of an RNA strand. It does this by reading the DNA template strand and incorporating complementary RNA nucleotides, effectively transcribing the genetic information from DNA to RNA.

5. Card 5

   Why is the 5' UTR (Untranslated Region) important for the initiation of translation?

   The 5' UTR is critical for translation initiation because it contains sequences that interact directly with the ribosome. This interaction helps to correctly position the ribosome on the mRNA, ensuring that translation begins at the appropriate start codon.

6. Card 6

   Describe the directionality of RNA synthesis and DNA template reading during transcription.

   During transcription, RNA is synthesized in the 5' to 3' direction. Concurrently, RNA polymerase reads the DNA template strand in the opposite, antiparallel direction, specifically from 3' to 5'.

7. Card 7

   How does an enhancer sequence influence gene expression, and where can it be located?

   An enhancer sequence increases the rate of transcription for a gene. It can be located in various positions relative to the gene, including upstream, downstream, or even within the introns of the gene itself or other genes.

8. Card 8

   What is the role of transcription factors in the process of gene expression?

   Transcription factors are proteins that bind to specific DNA sequences, playing a pivotal role in regulating gene expression. They can either activate transcription by recruiting RNA polymerase or repress it by blocking its access or activity.

9. Card 9

   Explain the function of mRNA in the process of translation.

   mRNA (messenger RNA) carries the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm. It contains the sequence of codons that dictates the specific order of amino acids to be incorporated into a polypeptide chain during protein synthesis.

10. Card 10

    What is the specific role of tRNA in decoding the genetic message during translation?

    tRNA (transfer RNA) molecules are responsible for delivering the correct amino acids to the ribosome during translation. Each tRNA has an anticodon that base-pairs with a specific codon on the mRNA, ensuring the accurate assembly of the polypeptide chain.

11. Card 11

    How does rRNA contribute to the formation of a polypeptide during translation?

    rRNA (ribosomal RNA) is a structural and catalytic component of ribosomes. Its primary function during translation is to catalyze the formation of peptide bonds between incoming amino acids, thereby linking them together to build the polypeptide chain.

12. Card 12

    What is the mechanism by which stop codons terminate translation?

    Stop codons do not encode an amino acid but instead recruit release factors to the ribosome. These release factors hydrolyze the bond between the completed polypeptide chain and the tRNA in the P-site, leading to the release of the newly synthesized protein and the dissociation of the ribosomal complex.

13. Card 13

    Define a point mutation and explain its potential impact on a gene.

    A point mutation is a type of mutation involving a change in a single nucleotide base within a DNA sequence. This small change can potentially alter the amino acid sequence of a protein, leading to altered protein function, loss of function, or even a gain of function.

14. Card 14

    How can radiation lead to mutations in DNA?

    Radiation is a significant cause of mutations because it can induce double-stranded breaks in the DNA molecule. These breaks are severe forms of damage that, if not repaired correctly, can lead to chromosomal rearrangements or loss of genetic material.

15. Card 15

    Explain how polymerase slippage can result in an insertion mutation.

    Polymerase slippage occurs when DNA polymerase temporarily disengages from the template strand during replication, particularly in regions with repetitive sequences. When it re-engages, it may misalign, leading to the insertion of extra repeat units into the newly synthesized strand.

16. Card 16

    What is the function of aminoacyl-tRNA synthase in translation?

    Aminoacyl-tRNA synthase is an enzyme crucial for translation because it is responsible for attaching the correct amino acid to its corresponding tRNA molecule. This 'charging' of tRNA ensures the accuracy of protein synthesis by matching the right amino acid to the right codon.

17. Card 17

    Why are cell membranes described as a phospholipid bilayer with embedded proteins?

    Cell membranes are described this way because their fundamental structure consists of two layers of phospholipid molecules, whose hydrophilic heads face outwards and hydrophobic tails face inwards. Embedded within this bilayer are various proteins that perform diverse functions, such as transport, signaling, and enzymatic activity.

18. Card 18

    How do chemical agents cause mutations in DNA?

    Chemical agents can cause mutations by directly modifying the chemical structure of DNA bases. For example, some agents can convert an amino group to a carbonyl group, altering the base pairing properties and leading to errors during DNA replication.

19. Card 19

    What are the three main steps of translation, and what happens in each?

    The three main steps of translation are Initiation, Elongation, and Termination. Initiation involves the ribosome binding to mRNA at the start codon. Elongation is when tRNA brings amino acids to the ribosome, matching codons with anticodons to build the polypeptide. Termination occurs when a stop codon recruits release factors, ending translation and releasing the protein.

20. Card 20

    How do insertions and deletions differ from point mutations in their effect on gene sequence?

    Insertions and deletions involve the addition or removal of one or more nucleotides from the DNA sequence, respectively. Unlike point mutations, which change a single base, insertions and deletions can cause a frameshift, altering the reading frame and potentially changing every amino acid downstream of the mutation, often leading to a non-functional protein.

21. Card 21

    What is the general concept of gene expression regulation in molecular biology?

    Gene expression regulation refers to the complex mechanisms by which cells control which genes are turned on or off, and at what level. This regulation ensures that the right proteins are made at the right time and in the right amounts, allowing cells to adapt to their environment and perform specialized functions.

22. Card 22

    Explain how the interaction between the ribosome and the 5' UTR initiates translation.

    The 5' UTR (Untranslated Region) of an mRNA molecule contains specific sequences that are recognized by the ribosome. This interaction helps the ribosome to correctly bind to the mRNA and position itself at the start codon, ensuring that protein synthesis begins at the appropriate point.

23. Card 23

    What is the primary difference in function between mRNA and tRNA?

    mRNA (messenger RNA) carries the genetic instructions for a protein's amino acid sequence from the DNA to the ribosome. In contrast, tRNA (transfer RNA) acts as an adapter molecule, physically bringing the specific amino acids to the ribosome according to the codons on the mRNA.

24. Card 24

    How can mutations contribute to evolution?

    Mutations are the ultimate source of genetic variation, which is the raw material for evolution. While many mutations are harmful or neutral, some can lead to new traits that provide a selective advantage, allowing organisms to better adapt to their environment and pass these advantageous traits to future generations.

25. Card 25

    What is the significance of the 'start codon' in the initiation of translation?

    The start codon, typically AUG, is critical because it signals the precise point where translation should begin on the mRNA molecule. It also specifies the first amino acid (methionine) to be incorporated into the polypeptide chain, setting the reading frame for the entire protein synthesis process.

26. Card 26

    How does cholesterol regulate the fluidity of the cell membrane, and what is its dual effect at different temperatures?

    Cholesterol acts as a temperature buffer in the cell membrane. At low temperatures, it increases fluidity by preventing phospholipids from packing too closely. Conversely, at high temperatures, it decreases fluidity by restricting the movement of phospholipids, thus maintaining membrane integrity.

27. Card 27

    Distinguish between the roles of the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER) within the endomembrane system.

    The rough ER is primarily involved in the synthesis, folding, modification, and transport of proteins destined for secretion or insertion into membranes, due to the ribosomes attached to its surface. The smooth ER, on the other hand, is responsible for lipid synthesis, detoxification of drugs and poisons, and storage of calcium ions, lacking ribosomes.

28. Card 28

    Explain the mechanism by which stop codons terminate translation.

    Stop codons signal the end of translation by recruiting release factors to the ribosome. These release factors then catalyze the hydrolysis of the bond between the polypeptide chain and the tRNA in the P-site, leading to the release of the completed protein from the ribosome.

29. Card 29

    How do unsaturated fatty acids contribute to the fluidity of the cell membrane?

    Unsaturated fatty acids in phospholipids contain double bonds, which create kinks in their hydrophobic tails. These kinks prevent the fatty acid tails from packing tightly together, thereby increasing the spacing between phospholipids and enhancing the overall fluidity of the cell membrane.

30. Card 30

    Describe the function of aminoacyl-tRNA synthase in the process of translation.

    Aminoacyl-tRNA synthase is an enzyme crucial for translation, as it is responsible for attaching the correct amino acid to its corresponding tRNA molecule. This precise attachment, known as tRNA charging, ensures that the genetic code is accurately translated into the correct amino acid sequence of a polypeptide.

More flashcard decks

• Thermochemistry and Thermodynamics flashcards (149 cards)
• Género Bacillus y Clostridium flashcards (100 cards)
• Ψηφιακά Παιχνίδια και Μάθηση flashcards (100 cards)
• Philosophy AS flashcards (100 cards)
• Nervous system flashcards (100 cards)
• ECG, IGEL and Iv flashcards (100 cards)

Browse every shared deck