Term 1 Biology Reviewer Flashcards

Vocabulary flashcards generated from the comprehensive Term 1 Biology review notes covering biomolecules, molecular genetics, mutations, heredity, aberrations, rDNA, evolutionary history, and speciation.

Monosaccharides

The simplest carbohydrates that cannot be broken down into smaller sugar units, serving as an immediate energy source (e.g., glucose, fructose, galactose).

Glycosidic Bond

The covalent bond that joins two monosaccharide units together to form a disaccharide.

Polysaccharides

Long chains of monosaccharides that function in energy storage (starch, glycogen) and structural support (cellulose, chitin).

Triglycerides

The most common type of lipid, composed of 1 glycerol molecule and 3 fatty acid molecules, functioning in long-term energy storage and insulation.

Phospholipids

Lipids consisting of a hydrophilic head and hydrophobic tails with a phosphate group, forming the main structural component of cell membranes.

Amino Acids

The basic building blocks of proteins, linked together by peptide bonds; 20 common amino acids combine in different sequences to form various proteins.

Structural Proteins

Biological building blocks that provide physical support, shape, and mechanical integrity to cells, tissues, and organs (e.g., collagen, keratin, elastin, actin, tubulin).

Uniporters

Carrier proteins that transport a single type of molecule in one direction across a biological membrane.

Symporters

Carrier proteins that transport two different molecules in the same direction at the same time across a membrane.

Antiporters

Carrier proteins that transport two different molecules in opposite directions across a membrane.

Nucleotide

The basic building block of nucleic acids, consisting of a phosphate group, a pentose sugar (ribose or deoxyribose), and a nitrogenous base.

Complementary Base Pairing

The specific pairing of nitrogenous bases in DNA where Adenine pairs with Thymine and Cytosine pairs with Guanine, enabling accurate replication.

Friedrich Miescher

The Swiss biochemist who discovered DNA in 1869 by isolating a phosphorus-rich material called nuclein from white blood cells.

Transcription

The process by which enzymes make a single-stranded RNA copy of a DNA template strand inside the nucleus.

Translation

The process occurring on ribosomes where the sequence of nitrogen bases in mRNA is converted into a sequence of amino acids to form a protein.

Substitution Mutation

A genetic mutation that exchanges one base for another in the DNA sequence, such as the mutation causing Sickle Cell Disease by substituting valine for glutamic acid.

Huntington's Disease

An insertion mutation caused by a trinucleotide repeat expansion that creates an abnormally long protein that damages brain cells.

Fragile X Syndrome

An insertion mutation caused by a trinucleotide repeat expansion that acts as a genetic off switch, halting protein production entirely.

Cri du Chat Syndrome

A genetic disorder caused by a partial deletion of the short arm of chromosome 5 ($5p-$), leading to severe developmental and neurological impacts.

Frameshift Mutation

A mutation resulting from insertions or deletions that alter the reading frame of three-base codons, causing DNA sequences to be misparsed and producing truncated proteins.

Monohybrid Cross

A genetic cross between two parent organisms that differ by a single trait.

Law of Segregation

Mendel's law stating that during the production of gametes, two copies of each hereditary factor segregate so that offspring acquire one factor from each parent.

Incomplete Dominance

A non-Mendelian inheritance pattern where the phenotype of the heterozygote is intermediate between the phenotypes of the two homozygotes.

Codominance

A non-Mendelian inheritance pattern where both alleles for a trait are expressed equally in the phenotype rather than one allele masking the other.

Polygenic Inheritance

An inheritance pattern where a trait is controlled by two or more genes, each contributing a portion to the expressed phenotype (e.g., human eye color and skin color).

Structural Aberrations

Changes in chromosome structure caused by deletion, duplication, inversion, or translocation of chromosome segments.

Monosomy

An aneuploid condition ($2n - 1$) characterized by the absence of a single chromosome from a pair, such as Turner syndrome ($45, X$).

Polyploidy

A euploid condition ($>2x$) characterized by the presence of three or more complete sets of chromosomes in a cell.

Recombinant DNA

DNA molecules formed by laboratory methods of genetic recombination that bring together genetic material from multiple sources.

Werner Arber

The scientist credited with discovering restriction enzymes used to cut DNA molecules at specific target sequences.

Biolistic Method

A genetic modification technique using a gene gun to fire DNA-coated pellets into plant tissues to introduce expression plasmids into host cells.

Electroporation

A technique that uses an electric shock to expand plasma membrane pores, facilitating the insertion of recombinant DNA into host cells.

Flavr-Savr Tomato

The first genetically modified organism licensed for human consumption, engineered to slow its ripening process by inhibiting pectin degradation.

Bt-Corn

A genetically modified crop plant engineered to express a toxin from Bacillus thuringiensis that selectively kills Lepidoptera larvae such as the corn borer.

Crossing Over

The biological process occurring during the pachytene stage of prophase I in meiosis where non-sister chromatids of homologous chromosomes exchange genetic material at chiasmata.

Independent Assortment

The random alignment and separation of homologous chromosome pairs during metaphase I and anaphase I of meiosis, creating millions of potential chromosome combinations.

Ediacara Fauna

Oldest known fossils ($600\text{ M.Y.}$ old) of larger, multicellular, soft-bodied marine animals discovered in the Ediacara Hills, Australia.

Endosymbiotic Theory

The theory proposed by Lynn Margulis stating that eukaryotic cells evolved through early larger cells engulfing smaller bacteria that developed a mutualistic relationship and became mitochondria and chloroplasts.

Scala Naturae

The Great Chain of Being concept proposed by Aristotle, which classified living organisms in a fixed, permanent hierarchy from simplest to most complex.

Theory of Inheritance of Acquired Characteristics

Jean-Baptiste Lamarck's proposed mechanism of evolution based on the principles of use and disuse and the inheritance of traits acquired during an organism's lifetime.

Natural Selection

The process formulated by Charles Darwin and Alfred Russel Wallace where individuals with favorable inherited traits are more likely to survive, reproduce, and pass those traits to offspring.

Homologous Structures

Anatomical structures in different species that share a common evolutionary origin and structural arrangement, even if they perform different functions.

Analogous Structures

Anatomical features in different species that perform similar functions but evolved independently from dissimilar ancestral lines due to adaptive convergence.

Genetic Drift

The random loss of alleles in a population, which has a greater effect in small populations through mechanisms like the founder effect and bottleneck effect.

Biological Species Concept

The species definition associated with Ernst Mayr that defines a species as a group of actually or potentially interbreeding natural populations that are reproductively isolated from other groups.

Allopatric Speciation

The formation of new species that occurs when a physical geographic barrier separates a population into isolated groups, preventing gene flow.

Sympatric Speciation

The formation of new species without geographic separation, frequently driven by mechanisms such as polyploidy within the same geographic area.