BIO0005 Midterm Review

Active Site

The specific region of an enzyme where a substrate binds and catalysis takes place or where chemical reaction occurs. It is a structural element of protein that determines whether the protein is functional when undergoing a reaction from an enzyme.

Aerobic Metabolism

The process of cellular respiration that takes place in the presence of oxygen gas to produce energy from food.

Allele Population/Frequency

The allele frequency represents the incidence of a gene variant in a population.

Allele

The alternative form or versions of a gene. People inherit one allele for each autosomal gene from each parent.

Anaerobic Metabolism

The type of respiration through which cells can break down sugars to generate energy in the absence of oxygen.

Anchoring Junctions

Anchoring junctions are protein complexes that mediate the adhesion of cells to other cells or to the extracellular matrix.These multiprotein complexes are found in all cell types where they they stabilize the cells position, provide stability and rigidity, and support tissue integrity by holding cell sheets together.

Artificial Selection

An evolutionary process in which humans consciously select for or against particular features in organisms.

Autosome Chromosome

An autosome is one of the numbered chromosomes, as opposed to the sex chromosomes.

Bottleneck Effect (genetic drift)

When a disaster occurs which randomly kills individuals and removes their alleles from the population. Ex

Calorie

A calorie is the heat unit used in the estimation of the fuel value of various foods.

Capping

Capping is the first modification made to RNA polymerase II-transcribed RNA.

Cell

The smallest structural and functional unit of an organism

Cellular Respiration

Cellular respiration is a series of chemical reactions that break down glucose to produce ATP, which may be used as energy to power many reactions throughout the body.

Chemical Work

Chemical work in biology refers to the physical work that is carried out within a cell, due to the energy derived from chemicals, such like in diffusion.

Chromatin

The material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.

Chromosome

Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA).

Cilia

Cilia are small, slender, hair-like structures present on the surface of all mammalian cells.

Codominant Alleles

Codominance, as it relates to genetics, refers to a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual.

Codon

A codon is a DNA or RNA sequence of three nucleotides (a trinucleotide) that forms a unit of genomic information encoding a particular amino acid or signalling the termination of protein synthesis (stop signals). There are 64 signals (3 are stop signals).

Communicating Junctions

Communicating junctions mediate the passage of chemical or electrical signals from one interacting cell to its partner.

Complementary Base Pair

Complementary base pairs refer to the nitrogenous bases adenine, thymine, cytosine, and guanine.

Cytoplasm

Cytoplasm is the gelatinous liquid that fills the inside of a cell. It is composed of water, salts, and various organic molecules.

Cytoskeleton

The cytoskeleton is a network of protein fibres that form the structural network of the cell.

Cytosol

Cytosol is the liquid found inside of cells. It is the water-based solution in which organelles, proteins, and other cell structures float. (Fluid part of cytoplasm)

DNA Helicase

A DNA helicase is an enzyme that functions by melting the hydrogen bonds that hold the DNA into the double helix structure.

DNA Ligase

DNA ligase is an enzyme that joins DNA strands through the formation of phosphodiester bonds in a process called DNA ligation.

DNA Polymerase

DNA polymerase is a specific class of enzyme found in all living organisms. Its main purpose is to replicate DNA and to help in the repair and maintenance of DNA.

Deletion Mutation (Framework)

It is the loss of genetic material in the form of a DNA sequence or a specific part of the chromosome.

Diploid Cell

Diploid is a term that refers to the presence of two complete sets of chromosomes in an organism's cells, with each parent contributing a chromosome to each pair.

Directional Selection

A mode of natural selection in which a single phenotype is favoured, causing the allele frequency to continuously shift in one direction.

Disruptive Selection

A mode of natural selection in which extreme values for a trait are favoured over intermediate values.

Elongation (RNA)

The stage when the RNA strand gets longer, thanks to the addition of new nucleotides. During elongation, RNA polymerase "walks" along one strand of DNA, known as the template strand, in the 3' to 5' direction.

Enzyme Inhibitors (Competitive)

Any molecule that can bind to the active site of an enzyme with sufficient affinity such that it can compete with the enzyme's natural substrate and reduce enzyme activity as a result.

Enzyme Inhibitors (Non-Competitive)

A specific type of enzyme inhibition characterised by an inhibitor binding to an allosteric site resulting in decreased efficacy of the enzyme. An allosteric site is simply a site that differs from the active site- where the substrate binds.

Enzymes

Proteins that help speed up metabolism, or the chemical reactions in our bodies. They build some substances and break others down.

Eukaryotic Cell

Any cell or organism that possesses a clearly defined nucleus. The eukaryotic cell has a nuclear membrane that surrounds the nucleus, in which the well-defined chromosomes (bodies containing the hereditary material) are located.

Evolution

Descent with modifications (changes in traits of a population from generation to generation). Evolution occurs in a population when allele frequencies in a gene pool change from one generation to the next.

Extracellular Proteins

A protein that occurs in the space around a cell.

F1 Generation

It is the 1st filial generation obtained by crossing two different parents. The parents are quite distinct

F2 Generation

The second filial generation consists of the offsprings of the F1 generation. The F2 generation is defined as the result of a cross between two F1 individuals. The 3

Flagella

Flagella are microscopic hair-like structures involved in the locomotion of a cell.

Fluid Mosaic Model

The plasma membrane as a 'fluid` and a 'mosaic' structure. According to this model, the plasma membrane is a phospholipid bilayer structure composed of fluid and a mosaic of diverse molecules.

Founder Effect (genetic drift)

When a few individuals establish a new population (new location) and the allele frequency in the new population changes (creating a new gene pool).

Gene pool

The total amount of alleles in a population

Gene

The basic physical and functional unit of heredity. Genes are made up of DNA.

Germ Cell

A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually.

Golgi

A cell organelle that helps process and package proteins and lipid molecules, especially proteins destined to be exported from the cell.

Haploid Cell

Haploid refers to the presence of a single set of chromosomes in an organism's cells. In humans, only the egg and sperm cells are haploid.

Histone

A histone is a protein that provides structural support for a chromosome.

Homologous Pair

Two chromosomes in a pair – normally one inherited from the mother and one from the father.

Incomplete Dominance

A form of gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype. Ex

Induced Fit

It refers to an enzyme's shape and conformation changing over time in response to substrate binding. This makes the enzyme catalytic, lowering the activation energy barrier and increasing the reaction's completion rate.

Initiation (RNA)

Initiation is the beginning of transcription. It occurs when the enzyme RNA polymerase binds to a region of a gene called the promoter. This signals the DNA to unwind so the enzyme can ''read'' the bases in one of the DNA strands. The enzyme is now ready to make a strand of mRNA with a complementary sequence of bases.

Insertion Mutation (Framework)

A type of mutation that involves the addition of one or more nucleotides into a segment of DNA. Can involve the addition of any number of nucleotides.

Intermediate Filaments

Intermediate filaments form an elaborate network in the cytoplasm of most cells, extending from a ring surrounding the nucleus to the plasma membrane.

Kinetic Energy

The energy an object has because of its motion.

Lactic Acid

Lactic acid is a chemical your body produces when your cells break down carbohydrates for energy.

Lysosome

A membrane-bound cell organelle that contains digestive enzymes.

Mechanical Work

Protein attacher to a structure, the structure changes shape, and the muscle contracts (work happens).

Membrane Proteins

Protein molecule that is attached to, or associated with, the membrane of a cell or an organelle.

Mendel’s Principle of Segregation

The Law of Segregation states that alleles segregate randomly into gametes

Microfilaments

Protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton.

Microtubules

Microtubules are microscopic, hollow tubes made of alpha and beta tubulin that are a part of the cell's cytoskeleton. Microtubules extend throughout the cell providing it with proper shape and keeping the organelles in place.

Missense Mutation (Substitution)

A missense mutation is a DNA change that results in different amino acids being encoded at a particular position in the resulting protein.

Mitochondria

Membrane-bound cell organelles that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is called ATP.

Natural Selection

Natural selection is the process through which populations of living organisms adapt and change. Natural selection eliminates poorly adapted phenotypes.

Nondisjunction

Nondisjunction is the failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes. (Ex

Nonrandom Mating

Ex

Nonsense Mutation (Substitution)

A nonsense mutation, or its synonym, a stop mutation, is a change in DNA that causes a protein to terminate or end its translation earlier than expected. (Ex

Nuclear Membrane

A double layer that encloses the cell's nucleus, where the chromosomes reside.

Nucleolus

A spherical structure found in the cell's nucleus whose primary function is to produce and assemble the cell's ribosomes.

Nucleosome

A nucleosome is the structural unit of DNA packaging in eukaryotes. A nucleosome is basically DNA segments surrounded by histone protein octamers resembling a thread coiled around a spool.

Nucleus

The central and most important part of an object, movement, or group, forming the basis for its activity and growth.

Occluding Junctions

Occluding junctions seal cells together in an epithelium in a way that prevents even small molecules from leaking from one side of the sheet to the other.

P Generation

A simple P generation definition is the parental generation. The p generation is the original pair of parents at the start of a genetic cross experiment. The first generation that is produced by the p generation is called the F1 generation.

Pedigree

A table or list showing the line of ancestors of a person or animal.

Phospholipid Bilayer

A two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward.

Plasma Membrane

A microscopic membrane of lipids and proteins which forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and regulates the passage of molecules in and out of the cytoplasm.

Pleiotropy

Pleiotropy means that a single gene affects two or more characters. Ex

Polygenic Traits

A polygenic trait is a characteristic, such as height or skin colour, that is influenced by two or more genes.

Potential Energy

Stored energy that an object or system of objects may have based on their size, shape, position, or even material they are made from.

Prokaryotic Cell

Prokaryotic cells are cells that do not have a true nucleus and membrane-bound organelles.

Protein Receptors

Receptors are a special class of proteins that function by binding a specific ligand molecule. When a ligand binds to its receptor, the receptor can change conformation, transmitting a signal into the cell.

Ribosome

An intracellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell.

Rough ER

a cellular organelle composed of many folds of tissues and channels. It provides surface area for chemical reactions to take place. It is rough because its surface is covered with ribosomes.

Selective Permeability

Selective permeability of the cell membrane refers to its ability to differentiate between different types of molecules, only allowing some molecules through while blocking others.

Sex Chromosome

A sex chromosome is a type of chromosome involved in sex determination (X and Y).

Sexual Selection

Sexual selection is the process by which individuals compete for access to mates and fertilisation opportunities.

Silent Mutation (Substitution)

A silent mutation is a form of mutation that does not cause a major change in the amino acid. As a result, the protein remains active and functional.

Smooth ER

The main function of the smooth ER is to make cellular products like hormones and lipids.

Somatic Cell

All cells in the body other than sperm and egg cells.

Splicing

Splicing is a biological process where a newly synthesised pre-mRNA is transformed into a mature mRNA (during transcription).

Stabilising Selection

It favours the intermediate variants. Stabilising selection tends to remove the more severe phenotypes, resulting in the reproductive success of the norm or average phenotypes.

Substrate

The substance on which an enzyme can act.

Survival of the Fittest

An organism’s ability to survive long enough to reproduce (promoting any trait that increases fitness - even if it means death). Fittest = best adapted (have alleles with advantage) to survive and reproduce in the environment.

Termination (RNA)

Transcription termination occurs when a transcribing RNA polymerase releases the DNA template and the nascent RNA.

Testcross

A test cross is an experimental cross of an individual organism of dominant phenotype but unknown genotype and an organism with a homozygous recessive genotype (and phenotype). Testcrosses are used to determine whether a dominant phenotype is hetero or homozygous.

Transport Work

Protein attaches to a structure, the structure changes shape and moves substances.

True-Breed/Purebred

True breeding is a kind of breeding wherein the parents would produce offspring that would carry the same phenotype. This means that the parents are homozygous for every trait.