Biology-Unit 4: Cell Division and Reproduction

Style

A column-like part of the pistil that supports the stigma of a flower

Ovulate or Seed Cone

A female cone in gymnosperms. It produces seeds.

Complete Flower

A flower containing a pistil, stamen, calyx, and corolla.

Perfect flower

A flower having both male and female parts.

Female Flower

A flower that has female parts only. It has pistils, but no stamens.

Male Flower

A flower that has male parts only. It has stamens but no pistils.

Incomplete Flower

A flower that lacks one or more of the following parts: pistil, stamen, calyx, or corolla.

Sorus

A group of sporangia in ferns.

Gametophyte Generation

A haploid generation. Produces gametes.

Multiple Fission

A kind of asexual reproduction in which a single cell undergoes many mitotic divisions in the nucleus and a number of daughter cells are produced all at once.

Budding

A kind of asexual reproduction involving the growth of a new individual from part of an older organism. It can also refer to uneven distribution of cells that results in one cell receiving most of cell contents. In grafting, budding involves reducing the scion to a singular bud.

Sporic Life Cycle

A life cycle in which the sporophyte is more than the zygote, and the gametophyte is more than a gamete. The gametophyte and the sporophyte alternate with one another through time.

Annulus

A row of specialized cells around the sporangium of most ferns. It plays a role in opening the sporangium and releasing spores.

Microsporangium

A sporangium that produces microspores.

Meiospore

A spore produced by meiosis.

Sporangium

A spore-producing cell or structure in protists and plants.

Filament

A stalk which supports the anther. It is part of the stamen

Cell Plate

A structure that forms across the middle of a higher plant cell in telophase. It is the beginning of a new cell wall which divides the two daughter cells from one another to finish mitosis.

Ovule

A structure within the ovary of a flower that contains the female gametophyte. It develops into a seed after fertilization.

Heteromorphic Alternation of Generations

Alternation of generations in which the sporophyte and gametophyte generations have a different size, shape, or appearance.

Gametangium

An organ of lower plants, some protists and some fungi that produces gametes.

Binary Fission

Asexual reproduction in which a single cell divides into two with no exchange of genetic material; reproduction method of bacteria

Mitotic Division

Cell division by means of mitosis.

Homologous Chromosomes

Chromosomes that are the same in size, shape, and control the same characteristics. In higher animals and plants they occur in pairs.

Gymnosperm

Cone-bearing plant. Often called evergreen.

Chromosome

Discreet units of chromatin which appear during cell division. Each species has a fixed number of chromosomes.

Centriole

Forms the ends of the spindle fibers in the cell during mitosis. It is normally found in animal cells.

Homosporous

Producing spores that are all the same in size and shape.

Heterosporous

Producing spores that are different in size and shape.

Corolla

The collective term for the petals of a flower.

Calyx

The collective term for the sepals.

Sporophyte Generation

The diploid generation. One that produces spores by meiosis.

Pistil

The female part of the flower.

Prothallium

The gametophyte generation of a fern.

Alternation of Generations

The idea that the sporophyte generation and the gametophyte generations follow one another in alternating fashion.

Stamen

The male organ of plants. It produces pollen.

Stigma

The sticky, terminal end of the pistil where pollen is caught in pollination

Pollen Tube

The tube that grows from the pollen grain to penetrate the ovule for fertilization.

Pollination

Transfer of pollen from male to female cones in gymnosperms, or from anther to stigma in flowering plants.

Unicellular

One-celled

Oogamy

The condition of being oogamous.

Anisogamy

The condition of having anisogametes.

Anisogamete

The condition of having gametes similar in shape, but different in size.

Pupa

The developmental stage between larva and adult in insects undergoing complete metamorphosis. It is usually a resistant stage with a thick layer of material protecting the insect from drying out or being harmed by outside influences or forces of various kinds.

Ovum

The egg cell; a female gamete.

Ovary

The female gonad in animals. It produces eggs. Also, in plants it is the lower portion of the pistil that contains ovules and develops into fruit.

Juvenile

The first or earliest period of life in a young animal

Prophase

The first part of mitosis when the chromosomes shorten and thicken, the nucleolus breaks down, and the nuclear envelope disintegrates.

Fertilization

The fusion of gametes to produce a new cell or zygote. Often said to be the union of egg and sperm.

Anther

The part of the stamen of a flower that bears the pollen.

G2 Phase

The period during interphase between the synthesis of new genetic material and the beginning of mitosis

S Phase

The period of interphase when the genetic information is being duplicated.

Telophase

The phase of mitosis when the daughter chromosomes have reached opposite ends of the cell. The nuclear envelope and nucleolus reform and the process of cytokinesis begins

Metaphase

The phase of mitosis when the daughter chromosomes line up across the middle of the cell.

Root Stock

The portion o f a plant with the root system used in grafting.

Environment

The surroundings of an organism.

Metamorphosis

The transformation of a larva to an adult. It occurs only in animals having great differences in form between the larva and adult.

Hormone

A chemical substance made in one part of an animal or plant that causes some definite effect in the cells of another part of the same animal or plant.

Root Cutting

A cutting made from the root of a plant which develops adventitious buds and grows into a new plant.

Stem Cutting

A cutting of stem tissue used to grow a new plant.

Tuber

A fleshy, enlarged stem of a rhizome or stolon. It has buds and can grow new plants.

Colony

A group of organisms attached to one another after undergoing asexual reproduction from a common parent.

Organ

A group of tissues with a specific function in a part of the body.

Tissue

A group or mass of cells having a common function.

Rhizome

A horizontal stem at or just beneath the surface of the ground which can give rise to aerial stems, roots, or to more rhizome tissue. Rhizomes are a principal means of asexual reproduction in many plants.

Meiosis

A kind of cell division involving halving the chromosome number. It is responsible for genetic recombination

Incomplete Metamorphosis

A kind of metamorphosis in which the change from larva to adult comes in several steps or stages.

Egg

A large gamete with stored food.

Haplontic

A life cycle in which meiosis occurs shortly after fertilization, and most of the life cycle is passed as a haploid.

Internal Fertilization

A mating pattern in which the male and female come close together and the male introduces the sperm into the body of the female where fertilization occurs.

Protist

A one- or few-celled organism with chromosomes. Many have characteristics of both animals and plants.

Interphase

A period in the life of the cell between two periods of mitosis.

Regeneration

A phenomenon in which organisms break into two or more parts and then each part grows into a new individual

Bulb

A plant structure with enlarged leaf bases and stored food surrounding a central bit of fleshy stem tissue.

Differentiation

A process changing cells or organisms from a generalized to a more specific or specialized condition. It often involves a reduction of the ability to reproduce or divide, and is usually not reversible.

Cone

A reproductive organ of gymnosperms having a central axis with radiate scales and bracts. Can either produce pollen or ovules.

Corm

A short, solid, enlarged underground stem used for food storage and for asexual reproduction

Organism

A single individual living thing.

Sperm

A small, flagellated male gamete that swims to the egg to fertilize it.

Spore

A small, resistant cell that can grow into a new organism. They may be produced either by meiosis or mitosis

Conidia

A special kind of asexual spore found in many kinds of fungi

Mitospore

A spore that develops by mitosis.

Stolon

A stem which grows out from a plant periodically producing new stems and leaves on one side, and roots on the other. It is a means of asexual reproduction.

Spindle Apparatus

A system of fibers stretching from one end of a mitotic cell to the other end

Leaf Cutting

A technique in horticulture using a cutting made from a leaf or leaf tissue to grow a new plant.

Grafting

A technique used in horticulture in which a part of the stem or a bud is inserted into a plant with a good root system. The inserted portion of the stem or the bud then becomes the top part of the plant, and it uses the root system it was grafted into.

Diplontic

A type of life cycle in which meiosis produces gametes and the bulk of the life cycle is passed as a diploid. Adults are diploid

External Fertilization

A type of mating pattern in which eggs and sperm are released into the water after the mating partners come near one another. Fertilization occurs outside the body of the female.

Complete Metamorphosis

A type of metamorphosis in which the change from larva to adult occurs in one dramatic step. The larva and adult do not appear to be the same.

Tadpole

A young frog or toad in the larval stage of development.

Conjugation

An act of fertilization involving the transfer of cell contents to another cell. Usually occurs in simpler organisms.

Embryo

An early stage in the development of an animal or plant.

Archegonium

An organ in lower vascular plants, gymnosperms, mosses, and liverworts which produces and egg cell.

Antheridium

An organ in simpler plants that produces sperm cells.

Motile

Capable of independent movement.

Gonad

Gamete producing organs in animals.

Isogamete

Gametes that are the same in size and shape.

Haploid

Having a single, complete set of chromosomes. The chromosomes do not occur in matched pairs. A haploid cell has one half of each pair of homologous chromosomes.

Diploid

Having chromosomes in homologous pairs.

Oogamous

Having gametes of different size and shape. Usually these organisms have eggs and sperm.

Immotile

Incapable of independent movement.

Flagellum

Long, whip-like structure extending from a cell used for locomotion.

Chromatin

Material in the cell nucleus carrying hereditary information. It is made up of DNA and various kinds of protein.

Centromere

Part of a chromosome which attaches to the spindle apparatus during mitosis or meiosis.

G1 Phase

Period during the life of a cell between the finish of mitosis and the synthesis of more genetic material for another mitotic division

Vascular Plant

Plant which has true conductive tissues within it. It usually has true roots, stems, and leaves.

Adult

Refers to grown or mature animals or plants.

Adventitious

Refers to the appearance of buds or roots from tissue which is not bud or root tissue. Adventitious roots appear from stem or leaf tissue, and adventitious buds appear in root tissue.

Asexual Reproduction

Reproduction in which the offspring are genetic copies of the parent.

Gamete

Sex cell. Eggs and sperm are examples

Aquatic

Something which lives in or pertains to water.

Terrestrial

Something which occurs on the land or refers to the land.

Yolk

Stored food material in the egg of many animals.

Propagation

The act of propagating or establishing and growing new plants

Cytokenesis

The actual separation of daughter cells during cell division

Daughter Cell

The cell produced as a result of cell division.

Parent Cell

The cell which begins the process of cell division.

Central Disk

The central portion of a starfish. The arms of a starfish radiate from the central disk

Life Cycle

The idea that organisms reproduce from adult, to gametes, and back to adult again in a cycle or cyclical pattern.

Larva

The juvenile stage or phase of life of an organism which undergoes metamorphosis.

Testis

The male gonad in animals. It produces sperm.

Nuclear Envelope

The membrane that surrounds the nucleus of the cell

Furrowing

The method of cell division in animal cells in which there is a constriction in the middle of the parent cell until the two halves of the cell divide.

Genetic Recombination

The new genetic combinations of information which take place as a result of meiosis

Scion

The portion of a plant with buds, that is placed into the stock by grafting or budding.

Mitosis

The process of cell division in which one cell divides to produce two daughter cells that are genetic copies of the parent cell.

Zygote

The result of fertilization in which two gametes have fused together. Often simply called a fertilized egg.

Anaphase

The stage of mitosis when the chromosomes move to opposite ends of the cell.

Layering

The technique of developing roots on a stem of a plant while that stem is still attached to the parent plant. After a new root system is established the new plant is cut away from the parent plant and planted.