Biology Lecture Notes: Chapters 7, 8, and 9

A Comprehensive collection of vocabulary flashcards covering basic concepts of photosynthesis, stages of the cell cycle, meiosis, and Mendelian genetics principles based on lecture chapters 7, 8, and 9.

Autotrophs

Living entities that can make their own food without organic molecules from other living entities.

Photoautotrophs

Autotrophs that use energy of light to produce organic molecules (e.g., plants, algae, protists, and some prokaryotes).

Chloroplasts

Organelles consisting of photosynthetic pigments, enzymes, and other molecules grouped together in a membrane.

Chlorophyll

Light-absorbing pigment in chloroplasts that converts solar energy to chemical energy and is responsible for the green pigment in plants.

Mesophyll

Green tissue in the interior of a leaf where chloroplasts are concentrated.

Stomata

Tiny pores in the leaf that allow carbon dioxide to enter and oxygen to exit.

Stroma

Dense fluid within chloroplasts enclosed in an envelope of two membranes.

Thylakoids

A system of interconnected membranous sacs that segregate the stroma from the inner thylakoid space.

Light Energy

Energy captured by chlorophyll molecules providing boost for electrons and is therefore converted to chemical energy stored in sugar molecules

Light Reaction

The first stage of photosynthesis where solar energy is absorbed and converted to chemical energy in the form of $ATP$ and $NADPH$, powering the Calvin cycle.

Light Independent Reaction/Calvin Cycle

The second stage of photosynthesis occurring in the stroma; a cyclic series of chemical reactions using carbon from $CO_2$ along with $ATP$ and $NADPH$ to make $G3P$ (sugar).

Carbon Fixation

The incorporation of carbon from atmospheric $CO_2$ into organic compound carbons.

Photon

A fixed quantity of light energy; light behaves in this manner, and shorter wavelengths possess greater energy.

Pigments

Molecules that absorb wavelengths of light and sometimes transmit them.

Chlorophyll A

A chloroplast pigment that absorbs blue, violet, and red light and reflects green light.

Chlorophyll B

A chloroplast pigment that absorbs blue and orange light and reflects yellow-green light.

Carotenoids

Pigments that absorb blue-green light and reflect yellow and orange.

Chloroplast Pigments

Molecules responsible for absorbing photons and releasing electrons in an excited state.

Photosystems

Light-harvesting complexes surrounding a reaction center complex contained within the thylakoid membrane.

Reaction Center Complex

The part of a chloroplast photosystem where chlorophyll A molecules and a primary electron acceptor trigger the light reactions of photosynthesis.

Photosystem 1 (PS1)

The second photosystem to function, called $P700$ because it absorbs light with a wavelength of $700\,nm$.

Photosystem 2 (PS2)

The first photosystem to function, called $P680$ because it absorbs light with a wavelength of $680\,nm$ while splitting water.

Electron Transport Train

A bridge between photosystems 1 and 2 that provides the energy required for $ATP$ synthesis.

Chemiosmosis

The mechanism involved in both oxidative phosphorylation in mitochondria and the generation of $ATP$ in chloroplasts.

Photophosphorylation

The chemiosmotic production of $ATP$ during photosynthesis.

G3P

Glyceraldehyde-3-phosphate; an energy-rich, 3-carbon sugar produced by $CO_2 + ATP + NADPH$, sometimes used to make glucose.

RuBP (ribulose biphosphate)

A 5-carbon sugar that serves as the starting material for the Calvin cycle.

Rubisco

An enzyme that aids in the second step of carbon fixation.

Tubers

Thickened underground parts of a stem used by plants for the stockpiling of starch (along with roots and stems).

C3 Plants

Plants that use the Calvin cycle for the incorporation of $CO_2$ into organic material, forming a stable 3-carbon compound.

C4 Plants

Plants that preface the Calvin cycle with reactions that incorporate $CO_2$ into 4-carbon compounds, which then supply $CO_2$ to the Calvin cycle.

Photorespiration

The breakdown of a 2-carbon compound produced by the Calvin cycle in plants.

CAM Plants

Plants that conserve water by opening their stomata and admitting $CO_2$ only at night.

Greenhouse Effect

An atmospheric process in which gases like $CO_2$ keep the planet warm and support life by trapping reflected solar energy.

Global Warming

The slow and steady rise in the Earth's surface temperature due to the combustion of carbon-based fossil fuels.

Cell Division

Reproduction at the cellular level requiring the duplication of chromosomes and the sorting of chromosomes into new sets for daughter cells.

Prokaryote Chromosome

A singular circular $DNA$ molecule associated with proteins that is smaller than eukaryotic chromosomes.

Binary Fission

The process of prokaryotic cell division.

Chromatin

A complex consisting of one $DNA$ molecule and proteins that maintain the protein structure and activity.

Centromere

The region where two sister chromatids are held together before they divide into individual chromosomes.

Cell Cycle

An ordered sequence of events extending from the initial formation of a cell to its own division.

Interphase

A phase of the cell cycle involving the duplication of cell contents through $G_1$, $S$, and $G_2$ stages.

Mitotic Phase

The phase of the cell cycle consisting of the division of the nucleus (mitosis) and the division of the cytoplasm (cytokinesis).

Mitotic Spindle

A structure produced by centrosomes and composed of microtubules, required for the division of chromosomes.

Centrosomes

Structures in the cytoplasm that organize microtubule arrangement and contain a pair of centrioles in animal cells.

Prometaphase

The second stage of mitosis where the nuclear envelope fragments and spindle microtubules attach to the kinetochores of sister chromatids.

Cleavage Furrow

A structure formed from a contracting ring of microfilaments interacting with myosin that deepens to separate cell contents; found only in animal cells.

Cell Plate

A structure that forms in the middle of a plant cell from vesicles and grows outward to split the cell into two, creating a new plasma membrane and cell wall.

Cell Cycle Control System

A cycling set of molecules in the cell that trigger and coordinate key events in the cell cycle.

Checkpoints of Cell Cycle

Stages ($G_1$, $G_2$, $M$) that signal the cycle to proceed or stop an event.

G1 Checkpoint

A checkpoint that allows entry into the $S$ phase or causes the cell to enter the non-dividing $G_0$ phase.

Cancer Cells

Cells that escape the controls of the cell body, dividing rapidly and spreading to other tissues through the circulatory system.

Tumor

An abnormally growing mass of body cells.

Benign Tumors

Abnormal masses of cells that remain at their original site.

Malignant Tumors

Also called metastasis, these tumors spread to other sites in the body.

Carcinomas

Cancers that arise in external or internal body coverings.

Sarcomas

Cancers that arise in supportive and connective tissue.

Leukemias & Lymphomas

Cancers that arise from blood-forming tissues.

Somatic Cells

Body cells with 23 pairs of homologous chromosomes, with one member of each pair inherited from each parent.

Sex chromosomes

The $X$ and $Y$ chromosomes.

Autosomes

The 22 pairs of chromosomes that are not sex chromosomes and share the same size and genetics.

Homologous chromosomes

A pair of chromosomes that match in length, centromere position, and gene location.

Locus

The specific position of a gene on a chromosome.

Meiosis

Type of cell division that converts diploid nuclei into haploid nuclei.

Diploid cells

Cells that contain two homologous sets of chromosomes.

Haploid cells

Cells that contain only one set of chromosomes.

Gametes

Sperm and egg cells produced by the process of meiosis.

Fertilization

The union of a sperm cell and an egg cell.

Zygote

The cell resulting from fertilization, containing a diploid chromosome number with one set from each parent.

Growth Factor

A protein secreted by certain body cells that stimulates other cells to divide.

Density-Dependent Inhibition

A phenomenon in which crowded cells stop dividing.

Anchorage Dependence

The requirement that a cell must be attached to a solid surface to divide.

Synapsis

The pairing of homologous chromosomes.

Random Fertilization

Combination of each unique sperm with each unique egg increasing genetic variability

Genetic Recombination

The production of new combinations of genes resulting from crossing over.

Crossing Over

The exchange of corresponding segments between separate chromatids on homologous chromosomes.

Chiasma

The site where nonsister chromatids cross over.

Karyotype

An ordered display of magnified images of an individual's chromosomes arranged in pairs.

Trisomy 21

A condition involving the inheritance of three copies of chromosome 21; also known as Down Syndrome.

Nondisjunction

The failure of chromosomes or chromatids to separate normally during meiosis 1 or 2.

Polyploid Species

Species having two or more complete chromosome sets due to errors in meiosis or mitosis; widely observed in plants.

Chronic Myelogenous Leukemia (CML)

One of the most common leukemias, affecting cells that give rise to white blood cells.

Blending

A pre-Mendel model where sperm and egg blended into an inseparable essence in the offspring.

Spermist

A pre-Mendel model where the sperm carried the essence to be transferred to the egg for growth.

Ouists

A pre-Mendel model where the egg contained the essence and the sperm started the growth.

Gregor Mendel

The father of genetics who studied reproduction using garden peas.

Monohybrid Cross

The experimental mating of individuals to study one genetic locus.

Cross-Fertilization

The fertilization of one plant by pollen from another plant.

True-breeding

Varieties that, through self-fertilization, produce offspring identical to the parent.

Hybrids

The offspring resulting from the crossing of two different varieties.

P Generation

The parental generation.

F1 Generation

The first filial generation, or 'son'.

F2 Generation

The generation resulting from $F_1$ plants self-fertilizing or fertilizing each other.

Alleles

Alternative versions of genes that account for variations in inherited characters.

Homozygous

An organism that has two identical alleles for a specific gene.

Heterozygous

An organism that has two different alleles for a specific gene.

Dominant Allele

In a heterozygous pair, the allele that determines the organism's physical appearance.

Recessive Allele

In a heterozygous pair, the allele that has no noticeable effect on the organism's appearance.

Law of Segregation

Mendel's first law of inheritance stating that individuals have two alleles for each gene and these alleles separate during gamete formation in meiosis.

Punnett Square

A method used to find the probability of offspring genotypes and phenotypes.