General Biology: Photosynthesis, Cell Division, and Genetics

Vocabulary practice flashcards covering photosynthesis, light reactions, Calvin cycle, binary fission, mitosis, meiosis, and Mendelian inheritance.

Mesophyll

The interior leaf tissue consisting of cells that contain chlorophyll and chloroplasts for photosynthesis.

Stoma

Microscopic openings in leaves that regulate gas exchange by allowing $CO_2$ to enter and $O_2$ to exit.

Thylakoid

Inner membranous sacs within chloroplasts where the light-dependent reactions of photosynthesis occur.

Stroma

The fluid-filled space between the thylakoids and the chloroplast's inner membrane where the Calvin cycle takes place.

Chlorophyll a

The primary photosynthetic pigment that absorbs blue and red light, playing a central role in driving light reactions.

Chlorophyll b

An accessory photosynthetic pigment that absorbs blue and orange light and transfers energy to chlorophyll a.

Carotenoids

Accessory plant pigments that absorb blue and green light and reflect yellow, orange, and red wavelengths.

Photosystem

A protein complex embedded in the thylakoid membrane consisting of light-harvesting complexes surrounding a reaction-center complex.

Reaction-Center Complex

The core of a photosystem containing a special pair of chlorophyll a molecules and a primary electron acceptor.

Photophosphorylation

The production of ATP driven by a chemiosmotic $H^+$ concentration gradient established using light energy during the light reactions.

Rubisco

The enzyme that catalyzes the initial carbon fixation step of the Calvin cycle, combining $CO_2$ with RuBP.

Ribulose Bisphosphate (RuBP)

A five-carbon sugar molecule that serves as the carbon acceptor during the carbon fixation phase of the Calvin cycle.

Glyceraldehyde 3-Phosphate (G3P)

The three-carbon sugar product synthesized in the Calvin cycle using electrons from NADPH and energy from ATP.

Binary Fission

The method of asexual reproduction in prokaryotes where a single circular chromosome is duplicated and the cell divides into two identical daughter cells.

Plasmids

Small, accessory circular DNA molecules found in bacteria outside of the main circular chromosome.

Chromatin

The uncoiled complex of DNA and protein found in eukaryotic cells that condenses to form chromosomes during cell division.

Sister Chromatids

Two identical copies of a duplicated chromosome joined together at a shared centromere.

Centromere

The narrow region where two sister chromatids are held together and where kinetochores form.

Kinetochore

A specialized protein structure situated on the centromere to which spindle microtubules attach during cell division.

Cell Cycle

The ordered sequence of events extending from the time a cell is formed from a parent cell until its own division, encompassing Interphase and the Mitotic phase.

Mitosis

The division of the nucleus in eukaryotic cells that produces two nuclei with identical sets of chromosomes.

Cytokinesis

The physical division of the cytoplasm into two daughter cells following nuclear division.

Metaphase Plate

The imaginary plane equidistant between the two spindle poles where chromosomes align during metaphase.

Diploid ($2n$)

A cell or organism containing two complete sets of homologous chromosomes, one inherited from each parent ($2n = 46$ in humans).

Haploid ($n$)

A cell or organism containing a single set of unpaired chromosomes ($n = 23$ in humans).

Homologous Chromosomes

A pair of chromosomes that share the same size, centromere position, and carry genes coding for the same traits at identical loci.

Somatic Cells

Typical body cells of a multicellular organism that are diploid ($2n$) and divide by mitosis.

Gametes

Specialized haploid ($n$) reproductive cells, such as sperm and egg, produced via meiosis.

Tetrad

A four-part structure consisting of paired homologous chromosomes formed during prophase I of meiosis.

Heredity

The biological process of transmitting traits from parents to offspring across generations.

Genetics

The scientific branch of biology focused on the study of heredity and the variation of inherited characteristics.

Locus

The specific physical location of a particular gene along the length of a chromosome.

Allele

Alternative versions or molecular forms of a gene that code for variations of a character.

Homozygous

Having two identical alleles for a given gene on homologous chromosomes (e.g., $PP$ or $pp$).

Heterozygous

Having two different alleles for a given gene on homologous chromosomes (e.g., $Pp$).

Genotype

The specific genetic makeup or combination of alleles carried by an individual organism.

Phenotype

The observable physical traits and physiological characteristics expressed by an organism.

Law of Segregation

Mendel's principle stating that pair of alleles separate during gamete formation so that each gamete carries only one allele for each gene.

Monohybrid Cross

A genetic mating between two individuals that are heterozygous for a single character (e.g., $Pp \times Pp$), yielding a $3:1$ phenotypic ratio.

Dihybrid Cross

A breeding experiment involving individuals that are heterozygous for two distinct characters (e.g., $RrYy \times RrYy$).

Law of Independent Assortment

Mendel's principle stating that each pair of alleles segregates independently of other allele pairs during gamete formation, resulting in a $9:3:3:1$ F2 phenotypic ratio in a dihybrid cross.