Chapter 5a: The Molecular Basis of Inheritance Flashcards
Properties of a genetic material: (6)
- fidelity
- stability
- mutability
- capacity
- transmissibility
- translability
- Something about loyalty
- Genetic material must be faithfully replicated during cell division to maintain the integrity of genetic information from one generation to the next.
- A certain genetic material that has a low error rate (biology).
Fidelity
- The lower the number of errors, the more stable the genetic material
- Genetic material should possess ** to withstand environmental stresses and biochemical processes, ensuring the preservation of genetic information over time.
Stability
- ** is needed for species to survive and reproduce.
- While stability is important, genetic material must also be ** to allow for adaptation and evolution in response to changing environmental conditions or selective pressures.
Mutability
- Viruses do not dominate organisms because they have small genetic material
- Genetic material must have the ** to store and transmit the necessary amount of information required for the functioning and development of an organism.
Capacity
- Passing the genetic material to the next generation.
- Genetic material should be capable of being passed from one generation to the next through processes such as reproduction, ensuring the inheritance of traits from parents to offspring.
Transmissibility
- RNA → DNA, DNA → RNA → Polypeptide chain
- Genetic material should be ** into functional molecules, such as proteins or regulatory RNAs, to carry out cellular processes and determine the phenotype of an organism. This involves the ability to transcribe genetic information into messenger RNA (mRNA) and translate it into proteins through the ribosomal machinery.
Translatability
What does the relatively constant DNA content in diploid tissues suggest?
DNA’s role in genetic inheritance and maintaining genetic integrity.
What is the relationship between DNA content in haploid tissues and diploid cells?
The DNA content in haploid tissues is half that of newly formed diploid cells, indicating DNA replication during cell division.
What happens to DNA content during interphase and anaphase?
DNA content doubles during interphase, followed by equal distribution to daughter cells during anaphase, indicating DNA replication.
How does the DNA content in polyploid cells compare to normal cells?
Polyploid cells exhibit proportional increases in DNA content, supporting DNA’s role as the carrier of genetic information.
What effect does ultraviolet absorption of DNA have on organisms?
Ultraviolet absorption of DNA results in mutations in various organisms, highlighting DNA’s role in transmitting genetic information.
What do the experiments of Griffith (1928) and Zinder/Lederberg (1952) demonstrate?
The experiments demonstrate DNA transfer between bacteria, implicating DNA as the genetic material responsible for heritable changes.
What does the Hershey-Chase’s experiment support?
The Hershey-Chase experiment supports DNA, not protein, as the genetic material in bacteriophages, crucial for viral replication.
What did Griffith’s Experiment focus on?
Griffith’s Experiment focused on understanding the mechanism by which a virulent strain of pneumococcus bacteria causes disease.
What were the two forms of pneumococcus bacteria Griffith studied?
- virulent (disease-causing) strain
- non-virulent (harmless) strain of pneumococcus bacteria.
What did Griffith observe when he mixed the non-virulent pneumococcus bacteria with a heat-inactivated virulent strain and injected it into mice?
the mice developed pneumonia and died, indicating that the non-virulent strain had transformed into the virulent type.
What term did Griffith use to describe the phenomenon of the non-virulent strain transforming into the virulent type?
transformation
What did Griffith conclude from his experiment?
Griffith concluded that something from the heat-killed virulent strain had transformed the non-virulent strain into a virulent one.
What groundbreaking idea did Griffith’s experiment suggest?
Griffith’s experiment suggested that hereditary material from the dead virulent bacteria was being transferred to the non-virulent bacteria, transforming them into the disease-causing type.
What did Griffith’s findings pave the way for?
Griffith’s findings paved the way for further research into understanding the molecular basis of inheritance, ultimately leading to the discovery of DNA as the molecule responsible for carrying genetic information.
What did Oswald Avery, Colin MacLeod, and Maclyn McCarty seek to determine in their experiment?
They sought to identify the specific component of heat-killed virulent bacteria responsible for transforming non-virulent bacteria into virulent ones.
What were the three potential candidates Avery, MacLeod, and McCarty focused on?
- DNA (deoxyribonucleic acid)
- protein
- RNA (ribonucleic acid).
What were the results of treating the heat-killed bacteria with DNAase, protease, and RNAase?
Treatment with DNAase prevented transformation, indicating that DNA was the transforming principle. Treatment with protease or RNAase did not prevent transformation.
What did Avery, MacLeod, and McCarty’s experiment demonstrate regarding the transforming principle?
DNA is the transforming principle.
Avery, MacLeod, and McCarty’s experiment: What were the three potential candidates for the transforming principle?
DNA, protein, RNA.
Avery, MacLeod, and McCarty’s experiment:
Which enzyme did they use to degrade DNA?
DNAase
What are the two main cycles in the viral life cycle?
Lytic cycle and lysogenic cycle
the virus infects the host cell, replicates its genetic material, assembles new viral particles, and causes the host cell to burst, releasing new viruses.
lytic cycle
the virus integrates its genetic material into the host cell’s genome without immediately causing cell lysis. The viral DNA, known as a prophage, replicates along with the host DNA during cell division.
lysogenic cycle
Describe the general steps of viral replication. (5)
- Attachment: The virus attaches to specific receptors on the host cell.
- Entry: The virus injects its genetic material into the host cell or enters the cell through endocytosis.
- Replication: The viral genetic material hijacks the host cell’s machinery to replicate viral components, such as nucleic acids and proteins.
- Assembly: Newly synthesized viral components are assembled into complete viral particles.
- Release: Viral particles are released from the host cell, either by cell lysis or budding.
- a proposed mechanism for the origin of eukaryotic cells, suggesting that they arose through the fusion of multiple prokaryotic cells, particularly archaea and bacteria.
- suggests that eukaryotic cells originated from the endosymbiotic association of different prokaryotic cells.
Blender Hypothesis
molecular structure of DNA:
linear sequence of nucleotides held together by bridging phosphates
primary structure
- a British biophysicist and X-ray crystallographer.
- made significant contributions to the discovery of the structure of DNA.
- X-ray crystallography to study the structure of DNA molecules.
Rosalind Franklin
- played a key role in the discovery of DNA’s structure by providing critical X-ray diffraction images of DNA
- collaborated with Rosalind Franklin, providing her with access to DNA samples and facilitating her X-ray crystallography studies
- along with Watson and Crick, he was awarded the Nobel Prize in Physiology or Medicine in 1962 for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material.
Maurice Wilkins
states that in DNA, the amount of adenine (A) equals the amount of thymine (T), and the amount of cytosine (C) equals the amount of guanine (G).
Chargaff’s Rule
Who discovered Chargaff’s Rule?
Erwin Chargaff
Variant forms of DNA (4)
- B DNA
- A DNA
- Z DNA
- Triple helical DNA
Nucleic acid folding (7)
- Palindrome
- Mirror-repeat
- Hairpin
- Cruciform
- Tetraplexes in telomeres
- Triple helix
- tertiary structure-tRNA
- Produces ribosomes.
- Builds ribosome subunits from ribosomal RNA (rRNA) and proteins.
- Subunits exit through nuclear pores to the cytoplasm and combine to form functional ribosomes.
nucleolus
Function:
- Protein production.
Structure:
- Composed of rRNA and proteins.
- Consists of two subunits that combine during protein synthesis.
ribosomes
Types of Ribosomes (2)
- free ribosomes
- bound ribosomes
- Ribosomes that are located in the cytosol.
- synthesize proteins that function within the cytosol.
free ribosomes
- Ribosomes attached to the endoplasmic reticulum.
- Synthesize proteins for export or for membranes.
Bound ribosomes
