Biology 2021: Content Updates and Revisions

Note: This article provides general information about biology concepts in 2021, it may not encompass all necessary content. You should consult additional textbooks and teachers to ensure a comprehensive understanding of the subject.

Evolution and Origins

• Primate Evolution in the Cenozoic Era: The earliest primate fossils are found in the Paleocene epoch (around 66 million years ago) of the Cenozoic Era, indicating the early appearance and diversification of this group.

• The Rise of Birds, Mammals, Insects and Flowering Plants (Cenozoic Era): The Cenozoic is considered the age of mammals, birds, insects, and flowering plants. The extinction of dinosaurs at the end of the Mesozoic Era opened up opportunities for these groups to flourish.

• The Dominance of Reptiles and Gymnosperms (Mesozoic Era): The Mesozoic Era was the age of dinosaurs, flying reptiles, and giant marine reptiles. Gymnosperms were the dominant plant type during this period.

• The Rise of Vascular Plants and Amphibians (Paleozoic Era): The Paleozoic Era is marked by the emergence of the first vascular plants, paving the way for the evolution of terrestrial animals such as amphibians.

• Mammals Emerged in the Mesozoic Era: The earliest mammal fossils were discovered in the Triassic period (around 252 million years ago) of the Mesozoic Era. However, they were small and lived in hiding.

Genetics

• Gene Pairs Assort Independently of the Gene Determining Red Flowers: This gene pair can determine another trait, such as plant height, fruit shape, etc. Importantly, this gene pair must reside on different chromosomes to assort independently from the gene determining flower color.

• One Ostrich Germ Cell with Genotype BbXDY Undergoing Normal Meiosis Produces a Maximum of One Type of Gamete: Since ostrich sex is determined by the XY system, males will produce one type of gamete, BY.

• Incorrect Statement Regarding Agricultural Land Improvement: Inorganic nitrogen application does not help improve acidic soil. Inorganic nitrogen can actually increase soil acidity.

• Minerals that Help Plants Mobilize Nutrient Metabolism for Accumulation in Seeds and Fruits: Potassium ions (K+) play a critical role in nutrient metabolism and transport.

• A Gene Functioning Normally Is Moved to a New Location, Leading to Its Cessation of Function, Due to an Inversion Mutation: Inversion can alter the gene’s position, resulting in changes in gene activity, potentially even stopping its function.

Cell Biology and Physiology

• Carbon Enters the Cycle as CO2 through Photosynthesis: Photosynthesis is the process by which plants use light energy to convert CO2 and water into glucose and oxygen, incorporating carbon into the cycle.

• Embryo Transfer Characteristics: Embryo transfer produces numerous individuals with identical genotypes, facilitating the rapid propagation of high-yielding crops or animals with superior qualities.

• What Material Does a Cell Utilize to Synthesize the Polynucleotide Chain During Mitosis: During DNA replication, the cell uses nucleotides to create new polynucleotide chains.

• The Pouking Network Electrical Impulse Transmitted to Ventricular Cells: The Pouking network is the electrical conduction system in the heart, transmitting impulses from the AV node to ventricular cells, stimulating contraction.

• Genes Are Distributed Evenly: Alleles of the same gene pair are distributed evenly into two daughter cells during cell division.

• The Electrical Impulse from the AV Node Transmitted to the Bundle of His: The AV node controls the heart rhythm, transmitting impulses to the Bundle of His, which conducts the impulse from the atria to the ventricles.

• The Heart’s Automatic System: Sinoatrial Node → Atrial Muscle → Atrioventricular Node → Bundle of His → Purkinje Network → Ventricles

• Enzymes Capable of Unwinding: RNA polymerase unwinds DNA to create a template for transcription.

• Pigment That Converts Light Energy into ATP and NADPH Energy: Chlorophyll a is the primary pigment involved in photosynthesis, absorbing light energy to produce ATP and NADPH.

• Duplication Arises from Unequal Crossing Over During Prophase I of Meiosis: During unequal crossing over, a segment of a chromosome can be duplicated on the same chromosome.

• Function of the Vena Cava: Transports oxygen-rich blood from organs to the heart.

Ecology

• Planting Legumes Increases Soil Nitrogen Content: Legumes have the ability to fix nitrogen from the air thanks to nitrogen-fixing bacteria in their root nodules, contributing to increased nitrogen levels in the soil.

• Limestone Powder Application Reduces Soil Acidity: Limestone powder contains calcium hydroxide, which helps neutralize acid in the soil, reducing acidity.

• Organic Fertilizers and Microbial Fertilizers Reduce Soil Acidity: Organic and microbial fertilizers improve soil structure, enhance the activity of beneficial microorganisms, and contribute to reducing acidity.

• Inorganic Fertilizer Application Increases Soil Acidity: Inorganic fertilizers often contain acidic components, which can increase soil acidity.

• After Measuring a Person’s Blood Pressure, Waiting 5-8 Minutes Before Measuring the Next Person: This waiting period allows the previous person’s blood pressure to return to normal, ensuring accurate measurements for the subsequent person.

• Avoid Strong Electromagnetic Fields When Measuring Blood Pressure: Electromagnetic waves can interfere with the operation of blood pressure monitors, leading to inaccurate results.

• In Plant Respiration Experiments, Pouring Water into the Flask Aims to: Push CO2 into the test tube to determine the plant’s respiration.

• All Species Share the Same Genetic Code, Known as Universality: The genetic code is the system for encoding genetic information and is universally used by almost all living organisms.

• Multiple Codons Determine One Amino Acid, Known as Degeneracy: Some amino acids are encoded by multiple codons.

• One Codon Encodes Only One Amino Acid, Known as Specificity: Each codon uniquely encodes a single amino acid.

• Universality is Evidence for the Common Origin of Species: The similarity in the genetic code is evidence of the close relationship between living organisms on Earth.

• The Process of Protein Synthesis is Translation: Translation is the process of converting genetic information from messenger RNA (mRNA) to a polypeptide chain (protein).

• Translation Always Involves Ribosomes, True: Ribosomes are organelles involved in translation, acting as protein synthesis “factories.”

• Translation Always Involves the Formation of Peptide Bonds Between Amino Acids, True: Peptide bonds are chemical bonds that link amino acids together to form polypeptide chains.

• Translocation Leads to the Exchange of Segments Between Two Non-Homologous Chromosomes: Translocation is the phenomenon where a chromosome segment breaks off and attaches to a different chromosome.

• Duplication Places Two Alleles of the Same Gene on the Same Chromosome: Duplication increases the number of gene copies, which can reside on the same chromosome.

• Can Duplication Create Conditions for Gene Mutations? Yes: Duplication creates conditions for gene mutations by increasing the number of gene copies, allowing mutations to arise in those copies.

• Inversion Can Cause a Gene that Was Functioning to Become Inactive When Moved to a New Location, True: Inversion can alter the gene’s position, affecting its activity, potentially rendering it inactive.

• The Discoverer of Linked Genes, Gene Mapping, and Sex Linkage is Morgan: Morgan was the scientist who conducted experiments with fruit flies and discovered these phenomena.

• The Discoverer of Extra-Nuclear Inheritance is Correns: Correns was the scientist who studied inheritance in cytoplasm and discovered extra-nuclear inheritance.

• The Laws of Segregation and Independent Assortment were Discovered by Mendel: Mendel was the scientist who discovered and formulated the two fundamental laws of inheritance: the law of segregation and the law of independent assortment.

• According to Mendel, Genetic Factors from the Father and Mother in the Offspring’s Cells Exist Separately, Not Blending Together: Mendel proposed that genetic factors (alleles) are transmitted from parents to offspring separately, without blending.

• According to Mendel, Alleles Determining High Fruit Yield Assort Independently of Alleles Determining Low Fruit Yield: Mendel’s law of segregation states that alleles assort independently into gametes.

• According to Mendel, Alleles Determining High Fruit Yield Assort Independently of Alleles Determining Red Flowers: Mendel’s law of independent assortment states that gene pairs located on different chromosomes will assort independently of each other.

• The Human Appendix and Coccyx are Vestigial Organs: These organs once had important functions during evolution but have now degenerated and lost their primary function.

• The Appendix and Cecum are Homologous Organs: They share a common origin and similar structure, but have different functions.

• Natural Selection Increases the Adaptive Level of Traits by Accumulating Alleles Involved in Determining Adaptive Traits. True: Natural selection is the primary driving force of evolution, eliminating less adapted individuals and maintaining those with traits suited to the environment, contributing to the accumulation of beneficial alleles.

• Natural Selection is the Primary Factor Shaping Adaptive Evolution: Natural selection is the primary driving force behind the adaptive evolution of species.

• Natural Selection Plays a Role in Filtering and Increasing the Number of Individuals with Adaptive Phenotypes Pre-Existing in the Environment: Natural selection filters out unfit individuals while maintaining and increasing the number of individuals with adaptive phenotypes.

• Mating Occurs to Form a Zygote, but the Zygote Does Not Develop, Representing Post-Zygotic Isolation: Post-zygotic isolation is a mechanism that prevents reproduction between species, occurring after the formation of a zygote but the zygote fails to develop into an individual.

• Different Reproductive Organ Structures Constitute Mechanical Isolation: Differences in reproductive organ structure can hinder mating between species, leading to reproductive isolation.

• Stratification in Communities is Due to Light: Light is a crucial factor influencing stratification within communities, creating distinct layers of trees, grasses, animals, etc.

• The Actual Lifespan of an Individual is the Ecological Age: Ecological age is the actual lifespan an individual reaches in a specific environment.

• The Potential Lifespan of an Individual is the Physiological Age: Physiological age is the maximum lifespan an individual can reach under ideal conditions.

• The Average Age of All Individuals is the Population Age: Population age is the average lifespan of all individuals in a population.

• Orchids Growing on Tree Trunks Represent a Commensalistic Relationship: Orchids benefit (a place to live) while the tree is not affected.

• Starlings and Buffalo Represent a Mutualistic Relationship: Both species benefit, starlings forage on buffalo backs, while buffalo are alerted to predators by the starlings.

• In Animal Cells, Genes Located in Mitochondria Are Not Distributed Evenly During Cell Division: Extra-nuclear inheritance (cytoplasmic) differs from nuclear inheritance, and mitochondrial genes may not be evenly distributed during cell division.

• Gymnosperms Arising in the Paleozoic Era: Gymnosperms emerged in the Devonian period (around 419 million years ago) of the Paleozoic Era.

• In the Digestive System of Animals, Glucose in Food is Absorbed by the Body Without Modification: Glucose is a simple sugar that can be absorbed directly by the body without modification.

• The Amino Acid Proline Has 4 Codons Determining It, While Glycine Has 4 Different Codons Determining It. A Chain with Two Proline and Glycine Amino Acids Will Have a Maximum of 8 tRNA Types: Each amino acid has 4 codons, so two amino acids can have a maximum of 4 x 4 = 16 tRNA types. However, in this case, the 4 proline codons and the 4 glycine codons are different, so the maximum number of tRNA types is 8.

• The Kidneys Participate in pH Regulation by Excreting H+ and Absorbing Na+: The kidneys play a crucial role in regulating blood pH by excreting H+ ions and absorbing Na+ into the blood.

• When Salt Intake Is High, the Kidneys Increase Water Reabsorption to Reduce Salt Concentration in the Blood: The kidneys regulate blood salt concentration by reabsorbing water and excreting excess salt through urine.

• The Lungs Participate in pH Regulation by Excreting CO2: The lungs expel CO2, reducing the concentration of carbonic acid (H2CO3) in the blood, thereby contributing to pH regulation.

• When Blood Glucose Levels Increase, the Pancreas Secretes Insulin to Convert Glucose into Glycogen: Insulin is a hormone released by the pancreas that lowers blood sugar levels by promoting the conversion of glucose into glycogen for storage in the liver and muscles.

• When Blood Glucose Levels Decrease, the Pancreas Secretes Glucagon to Convert Glycogen into Glucose: Glucagon is a hormone released by the pancreas that raises blood sugar levels by promoting the conversion of glycogen into glucose.

• When Blood pH Decreases, Buffer Systems Enhance the Removal of H+ Ions to Bring the pH Back to Normal: Buffer systems in the blood can neutralize H+ ions to maintain stable pH levels.

• The Element Magnesium (Mg) Is a Component of Chlorophyll: Magnesium is a component of chlorophyll, playing a crucial role in photosynthesis.

• What Type of Mutation Is Replicated in One Tissue and Expressed as a Phenotype in Part of the Body? Dominant Somatic Mutation: A dominant mutation in a somatic cell (soma) will be expressed as a phenotype in part of the body, depending on the location of the mutated cell.

• Polyploid Individuals Are Reproductively Isolated from the Diploid Forms That Gave Rise to Them: Differences in chromosome number between polyploid individuals and diploid forms lead to reproductive isolation between them.

• Communities That Recover After Destruction May Become Degraded Communities Due to Low Recovery Potential. True: The recovery potential of a community is influenced by factors such as biodiversity, environmental conditions, etc. Recovery may lead to degraded communities if sufficient conditions are not met to restore the original structure and function.

• Which Statement About Point Mutations Is True? 2. If the Mutation Does Not Change the Total Number of Hydrogen Bonds in the Gene, It Will Not Change the Gene’s Length: Point mutations can alter the number of hydrogen bonds, but they do not change the gene’s length if the mutation substitutes one base pair for another of the same type (e.g., A-T for G-C or vice versa).

• Triploidy Can Arise Due to Chromosome Non-Disjunction During Meiosis: During meiosis, if all chromosomes fail to segregate, a triploid gamete is produced, and when this gamete combines with a normal gamete, a triploid individual is formed.

• The Two Polynucleotide Chains in a DNA Molecule Are Linked by Hydrogen Bonds: Complementary base pairs (A-T and G-C) in the two polynucleotide chains of DNA are connected by hydrogen bonds.

• Red Light Synthesizes Glucides: Red light is a component of light energy utilized in photosynthesis to synthesize glucose.

• Blue-Violet Light Synthesizes Amino Acids: Blue-violet light energy is used in photosynthesis to provide energy for amino acid synthesis.

• The Flagellate Living Inside the Termite’s Gut Represents a Symbiotic Relationship: The flagellate benefits (habitat and food) while the termite benefits (digestion of wood).

• Aneuploidy Does Not Alter the Number of Genes on Chromosomes: Aneuploidy is a change in the number of chromosomes in a cell, but it does not alter the number of genes on chromosomes.

• Aneuploidy Always Alters the Amount of DNA in the Cell: Changes in chromosome number result in altered DNA content in the cell.

• Most Water Exists in Oceans, Lakes, and Ponds: Oceans and freshwater sources contain the vast majority of water on Earth.

• Biogeochemical Cycles Balance Matter, Not Energy Circulation: Biogeochemical cycles are cycles of matter circulation in nature, while energy is gradually lost with each cycle.

• What Measures Can Be Taken to Maintain and Strengthen Hybrid Vigor in Crops? Asexual Reproduction: Asexual reproduction helps to rapidly propagate crops with hybrid vigor, preserving desired traits.

• Insects Emerged in the Paleozoic Era: Insects emerged in the Silurian period (around 443 million years ago) of the Paleozoic Era.

• Communities with High Diversity Are More Stable in Structure: High biodiversity contributes to the stability of ecosystems, promoting ecological balance.

• All Species with Double Circulation Systems Undergo Gas Exchange in Alveoli. False: Birds have double circulation, but gas exchange does not occur in alveoli. Birds exchange gases in their lungs through a system of air tubes.

• All Species with Tubular Digestive Systems Have Closed Circulation Systems. False: Insects have a tubular digestive system but have an open circulatory system.

• All Species with Open Circulatory Systems Exchange Gases Using Tracheae. False: Clams have an open circulatory system but exchange gases through gills.

• UV Light Does Not Cause Gene Mutations: Gene mutations are alterations in the nucleotide sequence of DNA, and UV light does not cause gene mutations.

• Chromosome Duplication Always Leads to an Increased Number of Gene Copies at the Duplicated Location. False: Duplication can increase the number of gene copies but not necessarily at the duplicated location.

• The Right Atrium Receives Blood from the Vena Cava: The right atrium receives blood from the superior vena cava and inferior vena cava, which carry oxygen-poor blood back to the heart.

• Each Ecosystem Has One Food Web: Each ecosystem can have multiple food webs, creating a complex food web that interconnects different species.

• If a Population Is Not Subject to Mutagenic Agents and No Gene Flow Occurs, New Alleles Still Exist: The emergence of new alleles can occur due to gene mutations, even if the population is not exposed to mutagenic agents.

• For Tilapia, 5.6 Degrees Is Known as the Lethal Point: The lethal point is the minimum or maximum temperature that tilapia can tolerate.

• Respiration in Plants Always Produces ATP. False: Photorespiration, a type of respiration that occurs in C3 plants, does not produce ATP.

• In Unicellular Organisms, Only Intracellular Digestion Occurs: Unicellular organisms digest food through phagocytosis and intracellular digestion.

• All Animal Species Have Mechanical and Chemical Digestion. False: Some animal species, such as unicellular organisms, only have intracellular digestion or sac digestion.

• The Remora Fish Living Attached to Larger Fish Represents a Mutualistic Relationship: The remora benefits (habitat and food) while the larger fish is harmed (blood loss and health issues).

• Insects Flourished in the Cenozoic Era: Insects thrived and diversified in the Cenozoic Era, particularly after the extinction of dinosaurs.

• Assuming Goats Are Removed from an Ecosystem, Competition Between Two Grass Species Could Increase. True: Goats are herbivores. Their removal leads to increased competition between grass species due to the lack of herbivores to consume them.

• Inversion Can Increase the Protein Content of the Inverted Gene. True: Inversion can alter the gene’s position, leading to changes in the amount of protein synthesized.

• Can Aneuploidy Arise During Mitosis? Yes: Aneuploidy can occur during mitosis if chromosomes do not segregate evenly into two daughter cells.

Note: The content updates and revisions provided in this article are for informational purposes only. Consult additional resources and teachers to gain the most accurate knowledge.