BIOCUMUL

Vocabulary flashcards to review key concepts from the cell biology lecture.

Atomic Number

The number of protons in the nucleus of an atom, which determines the element's identity.

Atomic Mass

The total mass of an atom, approximately equal to the number of protons plus the number of neutrons in the nucleus.

Electron Configuration

The arrangement of electrons in the different energy levels and sublevels within an atom. Describes which orbitals are occupied by electrons.

Isotopes

Atoms of the same element that have the same number of protons but different numbers of neutrons, and therefore different atomic masses.

Covalent Bond

A chemical bond formed by the sharing of one or more pairs of electrons between atoms.

Ionic Bond

A chemical bond resulting from the electrostatic attraction between oppositely charged ions.

pH

A measure of the acidity or alkalinity of a solution, ranging from 0 to 14. pH values below 7 are acidic, pH values above 7 are alkaline or basic , and pH 7 is considered neutral.

Hierarchy of Biological Organization

The arrangement of biological structures from the simplest to the most complex, such as atoms, molecules, cells, tissues, organs, and organisms.

Monosaccharide

A simple sugar molecule, such as glucose or fructose, which cannot be broken down into simpler sugars.

Disaccharide

A sugar molecule composed of two monosaccharides joined together by a glycosidic bond, such as sucrose (glucose + fructose).

Phospholipid Bilayer

A double layer of phospholipid molecules that forms the basic structure of biological membranes. Lipid molecules are arranged with their hydrophobic tails oriented inward and their polar head groups facing the aqueous environment.

Osmosis

The net movement of water molecules across a selectively permeable membrane from a region of higher water concentration (lower solute concentration) to a region of lower water concentration (higher solute concentration).

Hypotonic Solution

A solution with a lower solute concentration compared to another solution (or a cell). In this case water will move into the cell.

Peripheral Protein

Proteins associated with the plasma membrane of a cell, but not embedded in the lipid bilayer. They are typically associated with the membrane through interactions with integral membrane proteins.

Integral Protein

A type of membrane protein that is permanently attached to the biological membrane. Significant portions of it are located within the hydrophobic core of the lipid bilayer.

Passive Transport

The movement of molecules across a cell membrane without the need for energy input by the cell. It relies on the concetration gradient for diffusion.

Active Transport

The movement of molecules across a cell membrane against their concentration gradient, requiring energy input (e.g., ATP) by the cell.

Permeability

The extent to which a membrane allows a substance to pass through it.

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration.

Potential Energy

Stored energy that can be converted into other forms of energy, such as kinetic energy or heat.

Entropy

A measure of disorder or randomness in a system.

Enthalpy

A thermodynamic property of a system that is equal to the sum of its internal energy and the product of the the system's pressure and volume.

Spontaneous Reaction

A reaction that occurs without the input of external energy. Also known as a exergonic reaction.

Terminal Electron Acceptor

A compound that receives or catches electrons at the end of the electron transport chain.

Aerobic Respiration

The process of cellular respiration that uses oxygen as the terminal electron acceptor.

Anaerobic Respiration

A form of cellular respiration that occurs in the absence of oxygen, using other molecules (e.g., sulfate, nitrate) as the final electron acceptor.

Fermentation

A metabolic process that produces energy from the oxidation of organic compounds in the absence of oxygen.

Glycolysis

The breakdown of glucose by enzymes, releasing energy and pyruvate.

Citric Acid Cycle

A series of chemical reactions that extract energy from acetyl-CoA.

Electron Transport Chain

A series of protein complexes that transfers electrons from electron donors to electron acceptors, couples with the transfer of protons (H+) across a membrane.

ATP Synthase

An enzyme that catalyzes the formation of ATP from ADP and inorganic phosphate, using a proton gradient (H+) as the energy source.

Substrate-Level Phosphorylation

The creation of ATP through the direct transfer of a phosphate group from an organic substrate to ADP by an enzyme.

Oxidative Phosphorylation

The metabolic pathway in which cells use enzymes to oxidize nutrients, thereby releasing energy which is used to reform ATP. Oxygen is the final electron acceptor.

Autotroph

An organism that produces organic compounds from inorganic substances using energy from sunlight (photosynthesis) or chemical reactions (chemosynthesis).

Cellular Respiration

A set of metabolic reactions and processes that take place in the cells of organisms to convert chemical energy from oxygen molecules or nutrients into adenosine triphosphate (ATP), and then release waste products.

Photophosphorylation

The phosphorylation of ADP to ATP using the energy of sunlight.

Photosystem

A biochemical mechanism in plants by which chlorophyll and other light-absorbing pigments absorb light energy and pass it on to other parts of the photosystem to generate chemical energy.

Non-Cyclic Electron Flow

A pathway that involves both photosystems I and II and produces ATP, NADPH, and oxygen.

Wavelength

The distance between successive crests or troughs of a wave, such as a light wave.

Photon

A particle of light, also known as a quantum of electromagnetic radiation.

Rubisco

An enzyme involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is converted by plants and other photosynthetic organisms to energy-rich molecules such as glucose.

Mitotic Cell Division

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

Meiotic Cell Division

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell.

Chromosome

A thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Anaphase

The stage of meiotic or mitotic cell division in which the chromosomes move away from one another to opposite poles of the spindle.

Cytokinesis

The cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.

Interphase

The resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.

Ploidy

The number of sets of chromosomes in a biological cell. Haploid = half and diploid = full number.

Gametes

A mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.

Independent Assortment

The principle, originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary traits assort independently during gamete production, giving different traits an equal opportunity of occurring together.

Homologous Chromosomes

Chromosome pairs (one from each parent) that are similar in length, gene position, and centromere location.

Allele

One of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent.

Homozygous

Having two identical alleles of a particular gene.

Genotype

The genetic constitution of an individual organism.

Phenotype

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

True Breeding

Organisms for which sexual reproduction produces offspring with inherited traits identical to those of the parents. The offspring are homozygous for those traits.

Dominant Allele

An allele that produces the same phenotype whether paired with an identical allele or a different allele. It masks the effect of the recessive allele.

Recessive Allele

An allele that produces its characteristic phenotype only when paired with an identical allele. Its effect is masked by the dominant allele.

Incomplete Dominance

A form of dominance in heterozygous condition wherein the allele that is regarded as dominant completely masks the effects of the recessive allele. The heterozygote results in a blended phenotype.

Codominance

A relationship between two versions of a gene. Individuals receive one version of a gene (allele) from each parent. If the alleles are different, the dominant allele will usually be expressed, while the effect of the other allele, called recessive, is masked. In codominance, however, neither allele is recessive and the phenotypes of both alleles are expressed. Both alleles are expressed.

Pleitropy

A situation in which a single gene influences multiple distinct phenotypic traits.

Linked Genes

Genes located close enough together on a chromosome that they tend to be inherited together.

X-linked Genes

A trait where a gene lies on the X chromosome. Sex-linked diseases are passed down through one of the sex chromosomes (X or Y).

Y-linked Genes

Traits or conditions caused by mutated genes on the Y chromosome. Only males are affected by Y-linked conditions, and all sons of an affected father will also be affected.

Barr Bodies

The inactive X chromosome in a female somatic cell, rendered inactive in a process called lyonization, in those species in which sex is determined by the presence of the X or Y chromosome.

Central Dogma of Molecular Biology

The process by which genetic information flows from DNA to RNA, to make a functional product such as a protein.

Silent Mutation

A mutation that does not result in a change in the amino acid sequence of the protein. Occurs because the genetic code is redundant (more than one codon can code for the same amino acid).

Missense Mutation

A mutation that results in the substitution of one amino acid for another in the resulting protein.

Nonsense Mutation

A mutation that results in a premature stop codon in the mRNA, leading to a truncated and often non-functional protein.

Frameshift Mutation

A mutation that shifts the reading frame of the mRNA, leading to a completely different amino acid sequence downstream of the mutation.

Promoter

A region of DNA where RNA polymerase binds to initiate transcription of a gene.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing a protein from an mRNA template.

Exon

In eukaryotic genes, a segment of a gene that is transcribed into mRNA and is translated into protein. Usually flanked by introns.

Intron

In eukaryotic genes, a noncoding sequence that is transcribed into mRNA but is removed by RNA splicing before translation.

Codon

A sequence of three nucleotides that corresponds to a specific amino acid or stop signal during protein synthesis.

mRNA

A type of RNA molecule that carries genetic information from DNA to the ribosome, where it serves as a template for protein synthesis.

rRNA

A type of RNA molecule that is a structural component of ribosomes, the site of protein synthesis.

tRNA

A type of RNA molecule that carries amino acids to the ribosome during protein synthesis, matching them to the codons on the mRNA.

Translation

The process by which ribosomes synthesize proteins using the sequence of codons in mRNA.

Terminator

A sequence of DNA that signals the end of transcription of a gene.

Gene

A sequence of DNA that codes for a functional RNA molecule (mRNA, tRNA, rRNA) or protein.

Phenotype

The observable characteristics of an organism resulting from the interaction of its genotype with the environment.

Genotype

The genetic makeup of an organism, including all the genes and alleles it carries.

Mutation

A change in the nucleotide sequence of DNA.

Frameshift Mutation

A mutation that results in the insertion or deletion of nucleotides in a DNA sequence, altering the reading frame of the mRNA.

Silent Mutation

A mutation that does not result in a change in the amino acid sequence of the protein due to the redundancy of the genetic code.

Missense Mutation

A mutation that results in the substitution of one amino acid for another in the resulting protein.

Nonsense Mutation

A mutation that introduces a premature stop codon in the mRNA, resulting in a truncated and often non-functional protein.

Emergent properties are characteristics of a system that arise from the interaction of the system's parts and may not be predictable from the individual parts alone.

Emergent properties refer to the way parts interact to form a complex whole with new characteristics.

Matter is anything that has mass and occupies space.

All biological structures are made of matter.

These are the three subatomic particles essential to atomic structure.

Atoms are composed of protons, neutrons, and electrons.

Protons and neutrons are found in the nucleus of an atom.

Electrons orbit outside the nucleus.

Protons have… , neutrons… have and electrons… have a

positive charge, no charge, negative charge

The number of protons in an atom determines its atomic number.

Atomic number identifies the element.

The number of protons equals the number of electrons in a neutral atom.

This balance results in a net neutral charge.

The atomic mass is calculated by adding the mass of protons and neutrons.

Electrons are negligible in mass.

In biology, atomic mass is commonly simplified by saying….. Although technically 1.007 and 1.009 respectively.

1 proton ≈ 1 Dalton and 1 neutron ≈ 1 Dalton.

In simplified atomic diagrams, lines or rings around the nucleus can represent energy levels, not actual electron paths.

Electrons do not follow neat orbits; this is an oversimplification.

Electrons are located in energy levels around the nucleus, not fixed paths.

This reflects the quantum nature of electron positioning.