General Biology 2 - Quarter 3 Module 1: Genetics, Evolution and Taxonomy

A set of 100 question-and-answer flashcards covering sex linkage, non-Mendelian inheritance, molecular structure of DNA/RNA, central dogma, recombinant DNA, geological timeline, mechanisms of evolution, and principles of taxonomy from General Biology 2 Quarter 3 Module 1.

What is a sex-linked gene?

A gene located on a sex chromosome.

Where are genes located on the Y chromosome found, and how are they inherited?

They are found only in males and are passed directly from father to son.

What is a pedigree?

A chart showing the presence or absence of a trait according to the relationships between parents, siblings, and offspring across generations.

What does a square symbol represent in a standard pedigree chart?

A male individual.

Why can an X-linked trait NEVER be passed directly from a father to his son?

Because a father passes his Y chromosome to his son, not his X chromosome.

Which sex is never affected by Y-linked traits?

Females.

What are the main inheritance features of X-linked recessive traits?

They are much more common in males; affected males pass the allele to ALL of their daughters and NONE of their sons; affected females have affected sons.

Why are daughters of males affected by X-linked recessive traits always carriers?

Because they inherit their father's single affected X chromosome, unless they also inherit an affected allele from their mother.

How do X-linked dominant traits differ in expression between males and females?

They occur more frequently in females, and ALL daughters of an affected male will be affected with no carriers.

What is the defining pedigree pattern of Y-linked traits?

There are no affected females, and ALL sons of an affected male are affected.

Which two genes on the X chromosome contribute to blood clotting control and cause hemophilia when mutated?

Two recessive genes carried on the X chromosome that help control blood clotting.

What are non-Mendelian inheritance patterns?

Inheritance patterns that do not follow one or more of Mendel's classic laws of genetics.

What is codominance?

An inheritance pattern where both alleles are expressed equally in the phenotype of the heterozygote.

What is incomplete dominance?

An inheritance pattern where the phenotype of a heterozygote offspring is intermediate between the phenotypes of both homozygous parents.

What phenotypic ratio results in the $F_2$ generation when two pink snapdragons ($C^R C^W$) are crossed?

$1\,\text{red} : 2\,\text{pink} : 1\,\text{white}$.

What is the definition of multiple alleles?

An inheritance pattern involving more than two alleles that code for a specific characteristic in a species.

What coat phenotype is produced in cattle when a brown fur allele ($B$) is co-dominant with a white fur allele ($W$)?

Roan fur ($BW$), consisting of both red/brown and white hairs.

What are the three alleles that determine human ABO blood groups?

Dominant $I^A$, dominant $I^B$, and recessive $I^O$ (or $A$, $B$, and $O$).

What genotypes correspond to human blood types A, B, AB, and O?

Type A ($I^A I^A$ or $I^A I^O$), Type B ($I^B I^B$ or $I^B I^O$), Type AB ($I^A I^B$), and Type O ($I^O I^O$).

In a complete dominance model, what phenotypic ratio is expected from a cross of two heterozygous parents ($Rr \times Rr$)?

$3:1$ (dominant to recessive phenotype).

In the Dela Cruz family, if Mrs. Dela Cruz is Type A and Mr. Dela Cruz is Type O, why can Luke (Type AB) NOT be Mr. Dela Cruz's biological child?

Because a father with Type O blood ($I^O I^O$) can only pass an $I^O$ allele, making it impossible to produce a Type AB ($I^A I^B$) child.

If a red-feathered cock and yellow-feathered hen produce all orange-feathered offspring, what mode of inheritance is demonstrated?

Incomplete dominance.

What three sub-molecules construct a single nucleotide?

A phosphate group, a five-carbon sugar, and a nitrogenous base.

What components form the repeating backbone of a DNA molecule?

Deoxyribose sugar and phosphate groups.

What is the sugar found in DNA compared to the sugar found in RNA?

Deoxyribose in DNA, and ribose in RNA.

What nitrogenous base in RNA replaces thymine found in DNA?

Uracil ($U$).

What are the complementary base pairing rules in DNA?

Adenine ($A$) pairs with Thymine ($T$), and Guanine ($G$) pairs with Cytosine ($C$).

What are the complementary base pairing rules in RNA?

Adenine ($A$) pairs with Uracil ($U$), and Guanine ($G$) pairs with Cytosine ($C$).

How do DNA and RNA differ in strand structure?

DNA is double-stranded, whereas RNA is single-stranded.

In nucleotide chemical structure, which functional component is highlighted at position 1 and 5 in this diagram?

The five-carbon sugar (deoxyribose/ribose).

What is a codon?

A three-nucleotide sequence in mRNA (such as AUG) that codes for a specific amino acid.

What biological function do proteins perform in cells?

They execute cellular functions as the functional products of genes.

What are the four structural levels of proteins?

Primary, secondary, tertiary, and quaternary levels.

Who proposed the Central Dogma of molecular biology, and in what year?

Francis Crick in 1956.

What directional sequence summarizes the Central Dogma of molecular biology?

Genetic information flows from $\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$.

What process converts DNA into RNA, and what process converts RNA into protein?

Transcription converts DNA into RNA, and translation converts RNA into protein.

What is semiconservative DNA replication?

Replication in which each resulting double-stranded DNA molecule consists of one original parent strand and one newly synthesized strand.

In what directional orientation are new DNA strands continuously synthesized?

In the $5' \rightarrow 3'$ direction.

How does leading strand synthesis differ from lagging strand synthesis during replication?

The leading strand is synthesized continuously ($5' \rightarrow 3'$), while the lagging strand is synthesized discontinuously in short stretches called Okazaki fragments.

What molecule provides the primer terminus required for lagging strand synthesis, and what enzyme synthesizes it?

An RNA primer molecule synthesized by primase (or RNA polymerase).

What is transcription?

The process where DNA is unwound and one strand is used as a template by RNA polymerase to produce an RNA molecule.

What are promoter regions in DNA?

Specific DNA regions that allow the binding of transcription factors to facilitate the binding of RNA polymerase.

What are the three major types of RNA produced during transcription?

Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

What is the role of tRNA during translation?

Various tRNA molecules carry specific amino acids from the cytoplasm to the ribosome during protein synthesis.

What is a Genetically Modified Organism (GMO)?

An organism produced through recombinant DNA technology containing DNA obtained from two different species.

What is genetic engineering or biotechnology?

The branch of science using recombinant DNA techniques to isolate, study, modify, or combine genes from different sources for practical purposes.

What is a vector in recombinant DNA technology?

A carrier used by scientists to transfer genetic material into a target cell.

What circular DNA molecules found in bacteria serve as vectors?

Plasmids.

What are the five main steps in the gene cloning technique?

1. Isolate gene of interest; 2. Insert gene into plasmid; 3. Insert plasmid into vector/bacterium; 4. Clone gene via bacterial fission; 5. Identify and harvest gene product.

How is human insulin commercially produced using recombinant DNA technology?

By inserting the human insulin gene into a bacterial plasmid to create transgenic bacteria that synthesize insulin in culture.

What is gene splicing?

A technique allowing specific isolation and movement of genes for desirable traits without including less desirable traits.

What are transgenes?

Genes of interest that are moved into an organism using recombinant DNA technology.

What is phytoremediation in the context of biotech crops?

The use of genetically modified crops to remove heavy metals from soil and water.

According to Rani and Usha (2014), what are the five steps in producing genetically modified crops?

1. Identifying and locating genes for plant traits; 2. Designing genes for insertion; 3. Transforming plants; 4. Selection of successfully transformed tissues; 5. Regeneration of whole plants.

What are two primary economic and agricultural benefits of GM crops?

Increased crop yields and resistance to pests and herbicides.

Approximately how many years ago did the history of life on Earth begin unfolding?

About $4.5 \times 10^9$ years ago (4.5 billion years ago).

What did Nicolas Steno publish in 1669 regarding rock layers?

The first laws of stratigraphy, stating that deeper rock layers are older than layers closer to the surface.

How did Giovanni Arduino categorize the rock layers of the Italian Alps in the 1760s?

Into Primary (metamorphic/volcanic), Secondary (hard sedimentary), and Tertiary/Quaternary (softer alluvial) layers.

How did William Smith contribute to geological time scale construction in 1819?

By matching rock ages across different geographical locations using comparative fossil remains.

What are eons in the geological time scale?

The largest intervals of geologic time, lasting hundreds of millions of years.

Into what three eras is the Phanerozoic Eon divided?

Paleozoic, Mesozoic, and Cenozoic eras.

What significant biological event marks the boundary between the Precambrian and Paleozoic eras?

The first appearance of animals with hard body parts.

What event marks the boundary between the Permian and Triassic periods?

A global extinction event that eliminated a large percentage of Earth's plant and animal species.

What is natural selection as an evolutionary mechanism?

The process through which naturally variable populations adapt and change as individuals with favorable traits survive and reproduce.

What is genetic drift?

Random chance events that cause unpredictable changes in allele frequencies within a population.

What is gene flow?

The movement of alleles into or out of a population due to individual migration.

How did zoologist Ernst Mayr classify reproductive isolation mechanisms?

Into pre-zygotic mechanisms (acting before fertilization) and post-zygotic mechanisms (acting after fertilization).

What is geographic or habitat isolation?

A pre-zygotic mechanism where potential mates occupy different habitats and never come into contact.

What is temporal or seasonal isolation?

A pre-zygotic mechanism where different groups reproduce at different times, seasons, or years.

What is behavioral isolation?

A pre-zygotic mechanism involving differences in courtship behaviors or mating calls.

What is mechanical isolation?

A pre-zygotic mechanism caused by structural differences in reproductive organs that prevent successful mating.

What is gametic isolation?

A pre-zygotic mechanism involving chemical or molecular incompatibilities between egg and sperm that prevent fertilization.

What is hybrid inviability?

A post-zygotic mechanism where a fertilized egg fails to develop during early embryonic stages.

What is hybrid sterility?

A post-zygotic mechanism where hybrid offspring reach adulthood but cannot produce viable gametes due to abnormal chromosome segregation during meiosis.

What is hybrid breakdown?

A post-zygotic mechanism where $F_1$ hybrids are fertile and viable, but $F_2$ offspring are weak or sterile.

What is allopatric speciation?

Speciation that occurs when population members become physically or geographically separated by barriers like mountains or bodies of water.

What is sympatric speciation?

Speciation occurring within the same geographical area, often driven by abrupt genetic changes such as polyploidization.

What early evolutionary view was shared by ancient philosophers Anaximander and Lucretius?

That all living things were related and transformed over time.

What was Aristotle's concept of the "Great Chain of Being"?

The belief that life was arranged fixedly from simplest to most complex, and that Earth was full with no new species possible.

What Creation date was calculated by Archbishop James Ussher based on Biblical chronology?

4004 BC.

What scientific contribution is credited to John Ray?

Providing the first formal definitions of the biological concepts of species and genus.

What taxonomic system was created by Carolus Linnaeus?

Binomial nomenclature and a hierarchical system of taxonomic classification.

What was Comte de Buffon's key contribution to evolutionary thought?

Recognizing the environment as an active agent of change in organisms.

What was Jean-Baptiste Lamarck's proposed mechanism of evolution?

The Theory of Use and Disuse (inheritance of acquired characteristics).

What concepts were introduced to science by Georges Cuvier?

The concept of extinction and the Theory of Catastrophism.

What theory of geological change was developed by Charles Lyell?

The Theory of Uniformitarianism.

What was Thomas Malthus's thesis regarding population growth and food supply?

That human population growth naturally outruns food supply capacity.

What evolutionary concept was co-proposed by Alfred Russel Wallace and Charles Darwin?

Evolution driven by Natural Selection.

What famous quote regarding evolution was stated by Theodosius Dobzhansky?

"Nothing in biology makes sense except in the light of evolution."

What are the five primary lines of evidence supporting evolution?

Biogeography, Fossil Record, Comparative Anatomy, Molecular Biology, and Direct Observation.

How does biogeography in Indonesia demonstrate evolutionary history?

Eastern Indonesian species resemble Australian fauna, while Western Indonesian species resemble Asian fauna, reflecting geological history.

What are homologous structures?

Physical features in different species that are structurally similar because they were inherited from a common ancestor.

What are analogous structures?

Structures in unrelated species that evolved independently to serve similar functions, not inherited from a common ancestor.

What are vestigial structures?

Reduced, non-functional structures in modern organisms that were fully functional in ancestral species.

How does comparative embryology support evolution?

Closely related organisms display striking anatomical similarities during early embryonic development before birth.

How does molecular biology provide evidence for common ancestry?

Universal similarities in DNA sequences, genetic code, and protein synthesis mechanisms across organisms.

What is direct observation of evolution?

Documenting small-scale evolutionary changes in organisms with rapid generation times, such as antibiotic resistance in bacteria.

What concept map summarizes the primary lines of evidence for evolution?

A mind map covering Proteins, Fossils, Geological Timeline, Genetics, and Comparative Anatomy.

Why are birds considered surviving descendants of dinosaurs in the fossil record?

Fossil records show modern birds represent the sole surviving lineage of archosaurs (dinosaurs).

What standard taxonomic hierarchy ranks organisms from broadest to most specific?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.