General Zoology and Biological Principles Vocabulary

Vocabulary flashcards covering key terms and concepts in animal body plans, embryology, Porifera classification and anatomy, sponge canal systems, and organic macromolecules.

Haploid

An organism or cell having only one complete set of chromosomes.

Diploid

An organism or cell having two sets of chromosomes or twice the haploid number.

Zygote

A fertilized egg cell produced by the fusion of male and female gametes.

Blastula

An early stage of embryonic development consisting of a hollow ball of cells surrounding a fluid-filled cavity.

Gastrulation

The process of infolding of the body wall of a blastula, forming a digestive tract and distinct germ layers.

Ectoderm

The outermost germ layer of an embryo that develops into the epidermis, nervous system, external sense organs, and mucous membrane lining the mouth and anus.

Endoderm

The innermost germ layer of an animal embryo that develops into the epithelium of the pharynx, respiratory tract, digestive tract, bladder, and urethra.

Mesoderm

The middle layer of embryonic cells that gives rise to muscles, blood, skeleton, and various internal systems.

Coelom

A fluid-filled body cavity formed during embryo development between internal organs and the body wall that is completely lined with mesoderm and acts as a shock absorber.

Acoelomate

An animal that lacks a coelom or body cavity.

Pseudocoelomate

An animal with a body cavity derived from mesoderm and endoderm rather than a true coelom completely lined with mesoderm.

Eucoelomates

Animals possessing a true coelom completely lined with mesoderm, where organs are suspended by mesenteries.

Cephalization

The concentration of sense organs, nervous control, and brain tissue at the anterior end of the body to form a head.

Protostome

An animal whose mouth is formed from the embryonic blastopore during early development.

Deuterostome

An animal whose anus is formed from the embryonic blastopore of a blastula.

Body plan

An animal's shape, symmetry, and internal organization.

Radial Symmetry

Body symmetry that generates identical body halves around a central axis.

Asymmetrical

Being irregular in shape and lacking any body symmetry.

Bilateral symmetry

Symmetry that generates two equal mirroring sides designated as left and right.

Anterior

Directional term denoting position towards the head end of an organism.

Posterior

Directional term denoting position towards the rear or anus end of an organism.

Dorsal

Directional term denoting the top side or back of an animal's body.

Ventral

Directional term denoting the underside or belly of an animal's body.

Phylum Porifera

A group of primitive, sessile, multicellular filter-feeding animals commonly known as sponges that possess pores and lack true tissues and organs.

Choanocyte

A flagellated collar cell in sponges that generates water currents to draw in oxygen and food and carry out waste.

Spongocoel

The central interior cavity of a sponge.

Ostia

Tiny pores or openings on the body surface of a sponge through which water enters.

Osculum

A large excurrent opening on a sponge body through which water exits.

Amoebocytes

Amoeboid cells in the middle layer of sponges that absorb food from choanocytes, digest nutrients, deliver them to other cells, and form skeletal spicules.

Spicules

Microscopic rigid skeletal structures made of calcium carbonate ($CaCO_3$) or silicon dioxide ($SiO_2$) that support the body framework of sponges.

Mesohyl

The gelatinous extracellular matrix separating the inner and outer cell layers of a sponge.

Archaeocytes

Undifferentiated embryonic amoeboid cells located in the mesohyl of sponges that can differentiate into sex cells or other cell types.

Sclerocytes

Specialized amoebocytes in sponges that produce spicules.

Spongin

A fibrous scleroprotein that provides flexible structural support in certain sponge skeletons.

Dermal ostia

Tiny incurrent pores located on the outer cell layer of sponges where water enters the internal canal system.

Asconoid system

The simplest body architecture in sponges, where flagellated choanocytes line the large central spongocoel.

Syconoid system

Sponge body design where the body wall is folded into radial canals lined with flagellated choanocytes.

Leuconoid system

The most complex sponge body layout consisting of distinct flagellated chambers connected by incurrent and excurrent canals.

Gemmules

Internal dormant buds produced asexually by sponges that can withstand unfavorable conditions and develop into new individuals.

Parenchymella

The ciliated, mouthless larval stage released by many fertilized sponges.

Class Calcispongiae

A class of marine sponges characterized by needle-shaped or 3-4 rayed spicules made of calcium carbonate ($CaCO_3$) and lacking spongin.

Class Hexactinellida

A class of deep-sea sponges, known as glass sponges, possessing six-pointed siliceous spicules that form a lattice-like structure.

Class Demospongiae

The largest sponge class, comprising ~90-95% of living species, characterized by leuconoid canal systems and skeletons of non-six-rayed siliceous spicules, spongin, or both.

Class Homoscleromorpha

A class of massive or encrusting sponges with simple, small spicules, viviparous reproduction, and amphiblastula larvae.

Amphiblastula

A free-swimming blastula larva with small flagellated cells in one hemisphere and large non-flagellated cells in the other.

Prosopyles

Minute openings or punctures in porocytes through which water passes from incurrent canals into radial canals or flagellated chambers.

Apopyles

Internal gastric openings through which radial canals or flagellated chambers empty into the spongocoel or excurrent canals.

Rhagon type

A canal system type in demosponges featuring a broad non-flagellated base (hypophare) and a conical upper wall (spongophare) containing small flagellated chambers.

Cleavage

The series of rapid mitotic cell divisions that a zygote undergoes immediately following fertilization.

Morula

A solid, mulberry-shaped ball of blastomere cells formed by early cleavage divisions.

Hox genes

A set of highly conserved developmental regulatory genes that dictate animal body orientation and morphological patterns.

Ediacaran biota

An early fossil group of soft-bodied animal organisms dating from 565 to 550 million years ago in the Neoproterozoic Era.

Cambrian explosion

A period 535 to 525 million years ago marking the rapid evolutionary diversification and earliest fossil appearance of major living animal phyla.

Diploblastic

Describing animals that develop from two primary germ layers: ectoderm and endoderm.

Triploblastic

Describing animals that develop from three primary germ layers: ectoderm, mesoderm, and endoderm.

Ecdysis

The periodic process of molting or shedding an outer exoskeleton, characteristic of Ecdysozoans.

Lophophore

A ciliated, tentacled feeding structure surrounding the mouth found in certain Lophotrochozoan phyla.

Trochophore larva

A distinctive ciliated, top-shaped larval stage characteristic of certain Lophotrochozoans such as molluscs and annelids.

Organic chemistry

The branch of chemistry primarily focused on the structure, properties, and reactions of carbon-containing compounds.

Biochemistry

The study of chemical processes and molecular substances occurring within living organisms.

Isomers

Compounds that share identical molecular formulas but have different structural arrangements of their carbon skeletons.

Hydroxyl group

A functional group consisting of a hydrogen atom bonded to an oxygen atom ($\text{-OH}$).

Carbonyl group

A functional group consisting of a carbon atom joined to an oxygen atom by a double bond ($\text{C=O}$).

Carboxyl group

A functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group ($\text{-COOH}$).

Amino group

A functional group consisting of a nitrogen atom bonded to two hydrogen atoms ($\text{-NH}_2$).

Phosphate group

A functional group consisting of a phosphorus atom double-bonded to one oxygen atom and single-bonded to three other oxygen atoms ($\text{-OPO}_3^{2-}$).

Monosaccharides

The simplest single-sugar carbohydrate monomers, such as glucose and fructose, with carbon skeletons containing 3 to 7 carbons.

Polysaccharides

Long-chain carbohydrate polymers formed by linking many monosaccharide monomers together via dehydration reactions.

Starch

A storage polysaccharide in plants built entirely from glucose monomers.

Glycogen

An extensively branched storage polysaccharide in animals composed of glucose monomers and stored mainly in liver and muscle cells.

Cellulose

A tough, insoluble structural polysaccharide composed of glucose monomers that forms the primary cell wall of plants.

Chitin

A structural polysaccharide used by arthropods to build their exoskeletons and found in fungal cell walls.

Lipids

A diverse class of hydrophobic, water-insoluble biological molecules composed mainly of carbon and hydrogen that serve in long-term energy storage.

Unsaturated fat

A fat containing fatty acids with one or more double bonds, causing kinks in the hydrocarbon chain and reducing the number of bound hydrogen atoms.

Saturated fat

A fat containing fatty acids with no carbon-carbon double bonds, carrying the maximum possible number of hydrogen atoms.

Phospholipids

Amphipathic membrane lipids consisting of a hydrophilic glycerol-phosphate head and two hydrophobic fatty acid tails.

Steroids

Lipids characterized by a carbon skeleton composed of four fused carbon rings, such as cholesterol and steroid hormones.

Enzymes

Specialized protein catalysts that increase the rate of chemical reactions in living cells without being consumed.

Peptide bond

The covalent linkage formed between the carboxyl group of one amino acid and the amino group of another through a dehydration reaction.

Denaturation

A process in which a protein loses its specific three-dimensional shape and biological function due to changes in pH, temperature, or salt concentration.

Primary structure

The specific, linear sequence of amino acids in a polypeptide chain encoded by genetic information.

Secondary structure

The localized coiling (alpha helix) or folding (pleated sheet) of a polypeptide chain maintained by hydrogen bonds along the polypeptide backbone.

Tertiary structure

The overall three-dimensional shape of a single polypeptide chain resulting from interactions among the R groups of its amino acids.

Quaternary structure

The functional structural level of a protein formed by the association of two or more individual polypeptide subunits.

Nucleotides

The monomer units of nucleic acids, consisting of a five-carbon sugar, a phosphate group, and a nitrogenous base.