Chapter 4

PAMP-triggered immunity

Relies on recognition of Pathogen-Associated Molecular Patterns (PAMPs) by toll-like receptors

Effectors

Inhibit PAMP-triggered immune responses and delivered into a plant cell

R proteins

Disease-resistance proteins produced by plants

Salicylic Acid

Produces at the site of pathogen infection prior to cell death during the hypersensitive response

Toll-like receptors

Recognize common pathogenic proteins and bind to these cells

Natural Killer Cells

A class of immune cells that identify abnormal surface proteins characteristic of some virus-infected and cancerous cells, then release chemicals that stimulate apoptosis (programmed cell death)

Mast Cells

Immune cells that are distributed in connective tissue and release histamine at sites of damage

Histamine

Acts as a signaling messenger, triggering inflammation to help fight invaders

Lymphocytes

Immune cells that bind antigens

Antigens

Surface proteins and polysaccharides of other cells (b cells and T cells)

Antibodies

Acellular proteins that bind the surface of pathogen cells in body fluids impeding infection (neutralization) and creating aggregate formations

Vaccines

Introduce antigens to a host to provoke a primary immune response, leading to immunological memory which can quickly activate in the case of reinfection by the same pathogen

Humoral immune response

A branch of adaptive immunity mediated by B cells, which produce antibodies to neutralize or destroy extracellular pathogens like bacteria and viruses in body fluids (humors)

Effector cells

Primary immune responses use to neutralize pathogen proliferation within the host

Memory cells

Remain in the body fluids as a deactivated form of immunity which can be quickly reactivated to yield renewed immune response if the same pathogen returns

Life cycle

The sequence of stages an organism undergoes from one generation to the next for reproduction

Gametes

Specialized haploid reproductive cells that contain a single set of 23 chromosomes

Mitosis

One chromosome duplication followed by one cell division, resulting in cells with the same number of chromosomes as the parent cells

Meiosis

One chromosome duplication, then two rounds of cell division, resulting in cells with half the number of chromosomes

Chromosomes

Thread like structures composed of DNA and proteins located within the nucleus of cells, serving as the carriers of genetic information

Homologous pair

Two chromosomes, one inherited from each parents, that posses thee same genes in the same order though they may have different alleles

Haploid

One set of chromosomes

Diploid

Two sets of chromosomes

Alternation of generations

Multicellular haploid and diploid stages alternate from generation to generation

Sporophyte

Produce haploid spores through meiosis

Gametophyte

Produces gametes through mitosis and these fuse at fertilization to form the diploid zygote

Plasmogamy

The cytoplasms of the parent mycelia fuse

Karyogamy

The haploid nuclei of two parents fuse, producing diploid cells

Convergent evolution

Similarities in the life cycle of fungi ad slime molds

Grex

An aggregate of cells that functions as a unit

Asexual reproduction

A single individual passes copies of all its genes to its offspring as a sole parents

Sexual reproduction

Produces offspring that have unique combinations of genes inherited from biological parents

Sperm

Generally small, less energetically costly to produce and many are produced by an individual

Eggs

Generally larger, more costly to produce, fewer per individual

Fragmentation

Vegetative buds or other parts of a plant can detach and develop into new offspring

breaking apart of the body into several pieces that develop into new organisms through regeneration

Apomixis

Some plants can produce mature seeds without pollination or fertilization. The embryo develops from a diploid cell in the ovule

Budding

New individuals are formed as outgrowths of an existing individual

Fission

A parent splits and separates into two individuals of about equal size

Regeneration

regrowth of missing body parts

Parthenogenesis

Offspring develop form unfertilized eggs

Simultaneous hermaphroditism

Sequential hermaphroditism

External fertilization

Females release eggs into the environment and males fertilize them outside the body

Internal Fertalization

Evolved structures or behaviors that lead to spermdeposition in or near the female reproductive tract

Selfing

Heterogamety

One sex has non-matching sex chromosomes (XY for mammals and flies (male heterogamety)) (ZW in birds(female heterogamety))

Environmental Sex Determination

External cues such as temperature, photoperiod, or social factors control sex determination

Haploidiploidy

Diploid females develop from fertilized eggs; haploid males develop from unfertilized eggs

Temperature sex determination

Social sex determination

Biological sex

Defined by what gamete an individual produces

Gender

How a person thinks about, identifies, and expresses themselves

Vegetative reproduction

Offspring arise from mature fragments of the parent plant

Isogamy

A form of sexual reproduction in which all gametes are the same size; common in unicellular eukaryotes and a few multicellular organisms obliging algae and some fungi

Anisogamy

A form of sexual reproduction in which gametes have different sizes; most multicellular organisms have evolved a large gamete (female) and a small gamete (male)

Dioecious

Plant species have separate individuals with male parts or female parts

Monoecious

Plants have both male and female parts on the same individual plant

External fertilization

Females release eggs into the environment and males fertilize them outside the body

Internal Fertilization

Have evolved structures or behaviors that lead to sperm deposition in or near the female reproductive tract

Gonochorism

Is a sexual reproductive system where each individual is either male or female

Hermaphroditism

An adaptation in which one individual has both male and female reproductive systems

Self-incompatibility

The ability of an organism to reject gametes of closely related individuals or itself

Apical meristem

A center or mitotic division at the apex of a root or shoot

Lateral meristems

Tissue in the vascular and cork cambiums responsible for secondary growth (width)

Vascular cambium

Produces additional layers of secondary xylem and phloem cells

Cork cambium

Produces layers of cork cells on the lateral side of the meristem

Auxin

Cell elongation, control f the apical dominance, cell division, preventing leaf abscission

Cytokinins

Cell division, auxiliary bud growth, seed germination

Abscisic Acid (ABA Acid)

Slow growth, seed dormancy

Ethylene

Fruit ripening, leaf abscission (shedding), senescence, growth around obstacles

Embryo sac

The female gametophyte develops in each ovule and consists of an egg and other cells

Pollen grain

A powder-like structure produced in the male parts of seed bearing plants

Endosperm

A nutrient rich tissue formed within the seeds of most flowering plants following double fertilization

Monocots

Angiosperms that have a single cotyledon, or seed leaf

Eudicots

Angiosperms that have TWO seed leaves

Fertalization

Forms a zygote

Cleavage

A series of mitotic divisions resulting in a hollow ball of cells

Blastula

A hollow ball of cells

Gastrulation

The blastula reorganizes into a multilayered structure called the gastrula, establishing the primary germ layers (ectoderm, mesoderm, endoderm)

Gastrula

An embryo with tissue layers

Organogenesis

Produces the rudimentary organs that will further develop into adult organs

Determinate growth

Organs stop growing once they reach a certain size

Blastocoel

The fluid-filled cavity that is surrounded by the blastula

Morphogenesis

The series of changes that shape the animal body

Blastopore

The first opening after the cells rearrange in three-dimensional space and an embryo with multiple cell layers forms

Diploblasts

Ectoderm and endoderm

Triploblasts

Ectoderm, endoderm, and mesoderm

Protosomes

First mouth of the embryonic opening

Deuterostomes

Second mouth of the embryonic opening

Organogenesis

Regions of the embryonic germ layers develop into rudimentary body organs

Differentiation

They specialize in structure and function based on a determined fate

Metamorphosis

Animals undergo a substantial change in form or structure after hatching or birth

Heterochrony

An evolutionary change in the rate or timing of developmental events

Paedomorphosis

When the timing of reproductive development is faster then development of non-reproductive organs

Homeotic genes

Are master regulatory genes that determine thee spatial organization of body parts in animals, plants, and fungi

Hox genes

Provide information about spatial organization in developing anima embryos, can produce major morphological differences

Metamerism

Organisms develop body plans with serial repetition of body parts

Tagmatization

A body condition in which metameres are grouped together for specific functions

Parasite

An organism that lives on or inside another organism and gets its food at the expense of the host

Ecology

The study of interactions between organisms and their environments