IB biology

What is the medium that life depends on for chemical reactions?

Water is the liquid medium that allows the chemistry of life to take place.

What is the composition of a water molecule?

Water (H2O) is made up of two hydrogen atoms covalently bound to one oxygen atom.

What property of water molecules results in cohesion?

Cohesion occurs due to the polarity of water molecules and their ability to form hydrogen bonds.

What is meant by water being polar?

Water molecules have a slight potential charge, with oxygen being slightly negative and hydrogen slightly positive.

How do hydrogen bonds affect the behavior of water droplets?

Cohesive forces cause water droplets to form as they try to minimize their surface area, resulting in a spherical shape.

What is adhesion in the context of water molecules?

Adhesion refers to the tendency of water molecules to stick to other polar or charged surfaces.

What is capillary action?

Capillary action is the movement of water due to adhesive forces that bond water to a surface, allowing it to rise.

What makes water a good solvent?

Water can dissolve many organic and inorganic substances that have charged or polar regions.

What are hydrophilic substances?

Hydrophilic substances are chemically attracted to water and readily dissolve in it.

What are hydrophobic substances?

Hydrophobic substances are insoluble in water and are typically nonpolar molecules.

How is glucose transported in plants?

Glucose is transported in plants dissolved in the water of the phloem.

What happens to oxygen in water during respiration?

Oxygen is a non-polar molecule that is barely soluble in water and is primarily carried by hemoglobin in red blood cells.

What is the heat capacity of water?

Water has a high specific heat capacity, meaning it requires a lot of heat to change temperature.

How does water serve as a coolant?

Water can absorb a lot of heat without a significant change in temperature, helping cool organisms in hot climates.

What is the significance of water being less dense as a solid?

Ice, being less dense than liquid water, floats, which provides insulation for aquatic habitats.

What is the principle behind DNA being the genetic material of living organisms?

DNA serves as the universal code for storing genetic information in all living organisms.

What is a genetic mutation?

A genetic mutation is a permanent change in the base sequence of DNA.

What is the difference between dominant and recessive alleles?

Dominant alleles express their traits in the presence of another allele, while recessive alleles only express their traits when both alleles are recessive.

What is the purpose of transcription in gene expression?

Transcription converts a gene into a messenger RNA (mRNA) transcript that can be translated into a protein.

How many base pairs does one triplet code for?

One triplet code, or codon, codes for one amino acid.

What is the function of ribosomes in protein synthesis?

Ribosomes create peptide bonds between amino acids to assemble polypeptides.

What is the role of tRNA in translation?

tRNA transports specific amino acids to the ribosome, matching complementary bases with mRNA codons.

How does the genetic code demonstrate universal common ancestry?

The similarities in the genetic code across diverse organisms support the theory of evolution and common descent.

What is a karyotype?

A karyotype is a visual representation of an individual's chromosomes, used to check for genetic abnormalities.

What is the difference between mitosis and meiosis?

Mitosis results in two identical daughter cells, whereas meiosis produces four genetically diverse haploid cells.

What does semi-conservative replication mean?

Semi-conservative replication means each new DNA molecule consists of one original strand and one new strand.

What is the role of helicase in DNA replication?

Helicase unwinds and unzips the DNA by breaking hydrogen bonds between complementary base pairs.

What is the catalyzing enzyme in the transcription process?

RNA polymerase is the enzyme that catalyzes the synthesis of RNA from a DNA template.

What is phenotypic plasticity?

Phenotypic plasticity is the capacity of an individual organism to alter its traits in response to environmental changes.

What does crossing over refer to in meiosis?

Crossing over is the exchange of genetic material between homologous chromosomes during prophase I of meiosis.

What technique is used to measure genetic variation in a population?

Chi-squared test is used to analyze the association between two species or genetic traits.

What is the difference between autosomes and sex chromosomes?

Autosomes are non-sex chromosomes, while sex chromosomes determine the biological sex of an organism.

What are the stages of the cell cycle?

The stages of the cell cycle include interphase (G1, S, G2) and mitosis.

What is the role of ATP in cellular activity?

ATP acts as the main energy carrier in cells, supplying energy for various biochemical processes.

What are the two types of anaerobic respiration?

Lactic acid fermentation and alcoholic fermentation are two types of anaerobic respiration.

What is the main outcome of mitosis?

Mitosis produces two genetically identical daughter cells, each with the same number of chromosomes as the parent cell.

What is the purpose of meiosis?

Meiosis is used to halve the chromosome number, producing genetically diverse haploid gametes.

What is a mutation's role in evolution?

Mutations introduce genetic variation which is essential for natural selection and evolution.

What is a stem cell niche?

A stem cell niche is a specialized microenvironment where stem cells are maintained and can differentiate when needed.

What is the genetic basis for diversity in blood types?

ABO blood groups are determined by multiple alleles where genes can produce A, B, AB, or O types based on specific carbohydrate structures on red blood cells.

What makes eukaryotic cells distinct from prokaryotic cells?

Eukaryotic cells have a nucleus and membrane-bound organelles, while prokaryotic cells do not.

What is the importance of glycolysis in cellular respiration?

Glycolysis breaks down glucose into pyruvate, producing a small amount of ATP and NADH in the process.

What is the universal genetic code?

The universal genetic code refers to the set of rules by which genetic information is translated into proteins in almost all living organisms.

How does temperature affect enzyme activity?

Increased temperature typically increases enzyme activity until the enzyme is denatured, which impairs function.

In what processes is ATP produced?

ATP is produced during glycolysis, Krebs cycle, and oxidative phosphorylation.

What is the significance of photosynthesis in ecosystems?

Photosynthesis converts light energy into chemical energy, producing oxygen as a byproduct and serving as the foundation for food webs.

How do mutations contribute to genetic diversity?

Mutations introduce new alleles into a gene pool, increasing variation that can be acted upon by natural selection.

What is transcription in protein synthesis?

Transcription is the process of creating mRNA from a DNA template, which occurs in the nucleus.

What happens during the process of translation?

Translation converts the sequence of mRNA into a specific sequence of amino acids, forming a polypeptide.

What is a phenotype?

The phenotype is the observable characteristics of an organism resulting from the interaction of its genotype and the environment.

How are genetic disorders inherited?

Genetic disorders can be inherited via alleles and are often classified as autosomal dominant, autosomal recessive, or sex-linked traits.

What are the roles of the major classes of biomolecules?

Carbohydrates provide energy, proteins perform various functions, lipids store energy, and nucleic acids store genetic information.

What is the role of restriction enzymes in genetic research?

Restriction enzymes cut DNA at specific sequences allowing for the analysis of fragments in various applications like cloning.

What is the law of segregation in genetics?

The law of segregation states that allele pairs separate during gamete formation, and each gamete carries only one allele for each gene.

What occurs during anaphase in mitosis?

During anaphase, sister chromatids separate and are pulled to opposite poles of the cell.

What is the central dogma of molecular biology?

The central dogma describes the flow of genetic information from DNA to RNA to protein.

What is a gene?

A gene is a segment of DNA that contains the instructions for building a protein or RNA molecule.

How do environmental factors influence phenotype?

Environmental factors can affect the expression of genes, leading to variations in phenotype despite identical genotypes.

What defines a wetland ecosystem?

Wetlands are defined by their saturated soil conditions and are crucial for biodiversity, water filtration, and flood control.

What are alleles?

Alleles are different versions of the same gene, contributing to genetic variation within a population.

How does the immune system recognize pathogens?

The immune system recognizes pathogens through specific glycoproteins present on their surfaces, which are detected by immune cells.

What is the biological significance of hydrogen bonds in water?

Hydrogen bonds allow water to have unique properties such as high surface tension, cohesion, and the ability to dissolve many substances.

What is the function of the Golgi apparatus?

The Golgi apparatus modifies, sorts, and packages proteins and lipids for storage or transport out of the cell.

What are spliceosomes?

Spliceosomes are molecular complexes that remove introns from pre-mRNA and splice exons together during RNA processing.

How does fermentation differ from respiration?

Fermentation is an anaerobic process that produces energy without oxygen, whereas respiration requires oxygen for the oxidative breakdown of glucose.

What is the significance of genetic variation within populations?

Genetic variation within populations is important for evolution and adaptation, allowing species to respond to environmental changes.

What is the impact of genetic drift on small populations?

Genetic drift can lead to significant changes in allele frequencies in small populations, potentially reducing genetic diversity.

What is the benefit of biodiversity in ecosystems?

Biodiversity enhances ecosystem resilience, productivity, and stability by providing varied genetic resources and ecological functions.

What are sex-linked traits?

Sex-linked traits are traits associated with genes located on sex chromosomes, often showing different patterns of inheritance in males and females.

What is the role of ATP synthase?

ATP synthase catalyzes the formation of ATP from ADP and inorganic phosphate during oxidative phosphorylation.

What is the significance of the Calvin cycle?

The Calvin cycle is crucial for converting carbon dioxide into glucose through energy derived from ATP and NADPH during photosynthesis.

What are multiple alleles?

Multiple alleles refer to the presence of more than two forms of a gene within a population, allowing for a range of phenotypes.

What is a pedigree chart?

A pedigree chart is a diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and allows for tracking genetic traits.

What does polygenic inheritance refer to?

Polygenic inheritance refers to the phenomenon where multiple genes influence a single trait, resulting in continuous variation.

What are the three main types of RNA and their functions?

mRNA carries genetic information from DNA to ribosomes, tRNA brings amino acids to ribosomes during protein synthesis, and rRNA is a component of ribosomes.

What is the difference between innate and adaptive immunity?

Innate immunity is the body's first line of defense, providing immediate response, while adaptive immunity provides a specific response that improves upon repeated exposure.