Biology Flashcards: Photosynthesis and Cellular Basis of Reproduction CHP 7+8

Vocabulary flashcards covering Chapter 7 (Photosynthesis) and Chapter 8 (The Cellular Basis of Reproduction and Inheritance) from Campbell Biology: Concepts & Connections (10th Edition).

Photoautotrophs

Organisms—including plants, algae, and protists and bacteria—that convert light energy into food and serve as producers for heterotrophic organisms.

provides electrons to PSII

H2O

enzyme used in phophosphorylation

ATP synthase

provides electrons to PSI

NADPH

cavlin cycle occurs here

Stroma

one of the products of light reaction

ATP through chemiosmosis in the thylakoid membrane

Heterotrophs

Consumers that cannot produce their own food and must feed on plants, animals, or decomposed organic material.

Chloroplasts

Double-membrane-bounded organelles in plant cells containing stacks of thylakoids and thick stroma fluid, where photosynthesis occurs.

Chlorophyll

A light-absorbing pigment located in chloroplasts that plays a central role in converting solar energy to chemical energy.

Stroma

The thick fluid enclosed by the inner membrane of a chloroplast, surrounding the thylakoids, where the Calvin cycle occurs.

Thylakoids

Interconnected membranous sacs inside a chloroplast where light reactions take place.

Granum

A stack of thylakoids within a chloroplast.

Carbon Fixation

The process during the Calvin cycle in which carbon from inorganic $CO_2$ is incorporated into organic compounds

RUBP+ CO2 —> rubisco (ENZ)—→ 2 molecules X PGA.

Redox Reaction (Photosynthesis)

A oxidation-reduction process in which $H_2O$ is oxidized (loses electrons) and $CO_2$ is reduced (gains electrons) to form sugar.

The Photosystem

A light-capturing unit in thylakoid membranes, consisting of light-harvesting complexes (antenna complex) surrounding a reaction-center complex.

Reaction-Center Complex

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

Primary Electron Acceptor

A structure in a photosystem's reaction-center complex that accepts photoexcited electrons from reaction-center chlorophyll a.

Photosystem II (PS II)

A photosystem whose reaction-center chlorophyll a molecule is called P680 because it best absorbs light at a wavelength of $680,\text{nm}$.

Photosystem I (PS I)

A photosystem whose reaction-center chlorophyll a molecule is called P700 because it best absorbs light at a wavelength of $700,\text{nm}$.

Photophosphorylation

The production of ATP in chloroplasts driven by chemiosmosis, using light energy to generate a proton ($H^+$) gradient across the thylakoid membrane.

Rubisco

The enzyme in the Calvin cycle that fixes $CO_2$ by attaching it to ribulose bisphosphate (RuBP).

(G3P)

An energy-rich 3-carbon sugar output produced by the Calvin cycle, used by plants to build glucose and other organic molecules.

Photorespiration

A process in $C_3$ plants occurring on hot, dry days when stomata close, causing rubisco to add $O_2$ to RuBP instead of $CO_2$, reducing photosynthetic yield by half.

C3 Plants

Plants that use the Calvin cycle directly for initial carbon fixation, forming a 3-carbon compound as the first product.

a decrease or drop of Co2 +rise in O2 stomata close divert the Calvin cycle in photorespiration

C4 Plants

Plants (such as sugarcane) + maize adapted to hot, dry climates that first fix $CO_2$ into 4-carbon compounds that provide Co2 to C.C even when stomata close on hot dry days to prevent loss of water

CAM Plants

Plants (such as cacti and pineapple) adapted to dry environments that open stomata at night to fix $CO_2$ into 4-carbon compounds, releasing $CO_2$ during the day for the Calvin cycle.

Greenhouse Effect

The warming of Earth's surface caused by greenhouse gases absorbing thermal radiation from the planet and re-radiating it back.

Asexual Reproduction

The creation of offspring by a single parent without the fusion of egg and sperm, producing genetically identical copies (clones).

Sexual Reproduction

The creation of offspring through fertilization of an egg by a sperm, producing genetically unique offspring.

Binary Fission

A form of asexual reproduction in typical prokaryotes where a single cell replicates its circular chromosome and divides in half into two daughter cells.

Chromatin

Thin, loosely packed fibers composed of DNA and associated proteins found in eukaryotic cell nuclei when the cell is not dividing.

Sister Chromatids

Two identical copies of a duplicated chromosome joined closely along their lengths, particularly at the centromere.

Centromere

The narrow region where two sister chromatids of a duplicated chromosome are held together most tightly.

Cell Cycle

An ordered sequence of events running from the time a eukaryotic cell is first formed until its own division into two cells.

Interphase

The stage of the cell cycle during which the cell grows, synthesizes DNA, and prepares for division, consisting of $G_1$, S, and $G_2$ phases.

part of the cell cycle wehn the cell is not dividing

Mitotic (M) Phase

The division phase of the cell cycle, which includes mitosis (nuclear division) and cytokinesis (cytoplasmic division).

Mitotic Spindle

A structure created by microtubules that associated proteins that guides the movement and separation of duplicated chromosomes during mitosis.

Centrosome

The microtubule-organizing center (MTOC) in animal cells containing a pair of centrioles, which duplicates during S phase to form the spindle poles.

Kinetochore

A multi-protein structure located at the centromere region of a sister chromatid where spindle microtubules attach.

Metaphase Plate

An imaginary plane equidistant between the two poles of the mitotic spindle where duplicated chromosomes align during metaphase.

Cleavage Furrow

A shallow constriction formed on the cell surface of animal cells by a contracting ring of microfilaments during cytokinesis.

Cell Plate

A double membrane structure formed across the midline of a dividing plant cell by the fusion of vesicles containing cell wall material during cytokinesis.

(Contact Inhibition)

The phenomenon in which normal cultured cells stop dividing once they come into contact with one another, forming a single monolayer.

Growth Factor

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

Cell Cycle Control System

A set of proteins within eukaryotic cells that triggers and coordinates key events and checkpoints (such as $G_1$, $G_2$, and M) in the cell cycle.

Apoptosis

Programmed cell death, which can be triggered at the $G_1$ checkpoint by p53 protein if DNA damage is deemed irreversible.

Malignant Tumor

An abnormal mass of cells capable of invading surrounding tissues and spreading throughout the body.

Metastasis

The spread of cancer cells beyond their original site to distant body tissues via blood or lymph vessels.

Somatic Cell

A typical body cell in a multicellular organism containing two sets of chromosomes (46 chromosomes in humans).

Homologous Chromosomes

A pair of matching chromosomes of the same length, centromere position, and gene loci, carrying genes for the same traits.

Allele

Alternative versions or forms of a gene located at the same locus on homologous chromosomes.

Autosomes

Chromosomes that are not directly involved in determining sex (the 44 non-sex chromosomes in humans).

Sex Chromosomes

The X and Y chromosomes that determine an individual's biological sex.

Meiosis

A type of cell division in sexually reproducing organisms that reduces the chromosome number from diploid ($2n$) to haploid ($n$), producing four genetically unique daughter cells.

MTOC (Microtubule organizing center)

A structure that organizes microtubules and is critical for cell division. It plays a key role in forming the mitotic spindle and anchoring centrioles 4 in total, ensuring proper chromosome segregation during cell division.

polar microtubules

structural components of the mitotic spindle that extend from the MTOC to help separate chromosomes during cell division.

elongate the cell away from each other, pushing the poles apart.