UNIT 1: CELL BIOLOGY
This mathematical relationship limits the maximum size of a cell, as a ratio that is too low prevents the efficient exchange of waste and nutrients.
Surface Area to Volume Ratio (SA:V)
Extreme pH or high temperatures cause this change in an enzyme’s structure, where the active site loses its shape and can no longer bind to the substrate.
Denaturation
These two specific events during Meiosis I ensure that every gamete produced by an individual is genetically unique.
Crossing Over and Random Orientation (Independent Assortment)
This term describes a group of populations of different species living together and interacting with each other in an area.
Community
The pentadactyl limb in humans, bats, and whales is this type of structure, which shares a common evolutionary origin despite performing different functions.
Homologous Structure
These protein-synthesizing organelles are size 70S in prokaryotes but size 80S in the cytoplasm of eukaryotes.
Ribosomes
This term describes the entire set of proteins expressed by a genome, cell, tissue, or organism at a certain time.
Proteome
This specific type of mutation in the Hb gene involves a single base substitution (GAG to GTG), resulting in Glutamic Acid being replaced by Valine.
Point Mutation (or Base Substitution Mutation)
This organic matter forms when plant material is inhibited from fully decaying by acidic and anaerobic conditions, usually in waterlogged soils.
Peat
Proposed by Carl Woese based on ribosomal RNA sequences, this classification level sits above "Kingdom" and divides all life into these three groups.
Archaea, Eubacteria (Bacteria), and Eukaryota
In animal cell membranes, this amphipathic molecule reduces membrane fluidity and permeability to some solutes, preventing the membrane from becoming too crystallized or too liquid.
Cholesterol
During DNA replication, these two specific enzymes are responsible for (1) unwinding the double helix and (2) linking nucleotides together in a 5' to 3' direction.
1, Helicase and 2, DNA Polymerase
In a dihybrid cross of two heterozygous parents (AaBb x AaBb), this is the expected phenotypic ratio of the offspring if the genes are unlinked.
9:3:3:1
This statistical test is used by ecologists to determine if there is a significant association between the distribution of two species in a habitat + explain the null and alternative hypothesies
Chi-Squared Test
Null Hypothesis (H0): There is no association (species are distributed independently).
Alternative Hypothesis (H1): There is a significant association (positive or negative).
If the calculated χ2 value is greater than the critical value, you reject H0.
This term describes the rapid evolution of a variety of species from a single common ancestor, often following the colonization of a new environment with diverse ecological niches.
Adaptive Radiation
This specific type of active transport involves the cell membrane folding inward to form a vesicle, allowing the ingestion of large particles or bulk fluids.
Endocytosis
The Polymerase Chain Reaction (PCR) relies on this specific enzyme, sourced from Thermus aquaticus, because it can withstand the high temperatures (95°C) needed to denature DNA.
Taq Polymerase
To determine if an individual showing a dominant trait is homozygous or heterozygous, they must be crossed with an individual possessing this specific genotype.
Homozygous Recessive
This process occurs when increased atmospheric CO2 dissolves in seawater, lowering the pH and reducing the concentration of carbonate ions needed by calcifying organisms.
Ocean Acidification
This evolutionary process explains why sharks (fish) and dolphins (mammals) have similar streamlined body shapes despite being only distantly related.
Convergent Evolution
In a common IB lab, this is the specific point on a graph where the line of best fit crosses the x-axis, representing a state where there is no net change in mass.
Isotonic Point
These isomers of unsaturated fatty acids are distinguished by the position of hydrogen atoms around a double bond; one occurs naturally and creates a "kink," while the other is linked to coronary heart disease.
Cis and Trans isomers
Because the gene for blood clotting is located on the X-chromosome and is recessive, this gender is significantly more likely to express the phenotype of hemophilia.
In genetic modification, this specific enzyme is used to "paste" a gene into a bacterial plasmid by forming covalent phosphodiester bonds.
Males
DNA Ligase
To determine if the distribution of two species is significant, you must compare the Observed frequencies to these, which are calculated using the formula: (row total×column total)/grand total.
Expected Frequencies
This term describes a population where two or more alleles are temporarily in flux due to changing environmental pressures, famously exemplified by the shift from light to dark peppered moths during the Industrial Revolution.
Transient Polymorphism