Cell communication and cycle vocab

Ligand

Signaling molecule

Neurotransmitter

Ligand used in nerve cell communication

Autocrine

Chemical signaling of a cell by itself

Paracrine

Chemical signaling between two nearby cells

Endocrine

Chemical signaling of two distant cells through the bloodstream

Juxtacrine

Chemical signaling of two touching or connected cells

Plasmodesmata

Channels that connect plant cells

Gap junctions

Spaces that in some cells that connect them to other cells and let small signaling molecules diffuse through

Reception

Receptor protein of the target cell receives the ligand

Signal transduction

Signal is passed through relay molecules

Response

Cell responds to the signal

Signaling cascade

Activation of a series of target proteins by relay proteins

Amplification

Increase in strength of a signal

Kinase

Enzyme type that adds phosphates to relay proteins, activating or (less frequently) inactivating them

Second messengers

Molecules in the cell that relay and amplify the signal

Gene expression

Process in which DNA is used to make proteins

Phenotype

Physical traits

Growth factors

Ligands that promote cell growth and division

Apoptosis

Programmed cell death

Homeostasis

Stable internal environment

Negative feedback

Bringing a too high level down or a too low level up (countering the stimulus)

Positive feedback

Maintaining and possibly accelerating the direction of the stimulus

Metabolic response

Enzymes become more or less active

Mitotic phase

Mitosis and cytokinesis

Chromatin

Relaxed DNA fibers

Centrosome

Two centrioles which create the spindle

Sister chromatids

Two identical halves of replicated chromosomes

Centromere

Where sister chromatids are connected

Equatorial plate

Theoretical line across the middle of the cell, similar to the equator

Cleavage

Cytokinesis process in animal cells

Cleavage furrow

Shallow groove in the cell surface, the first sign of cleavage occuring

Cell plant

Structure formed between the divided nuclei in plant cells that becomes the cell wall

G0

Nondividing state that occurs when cells exit the cell cycle

Binary fission

Asexual reproduction in prokaryotes

Cyclins and Cyclin-dependent kinases (Cdks)

Proteins responsible for the progress of the cell through checkpoints

Anchorage dependence

Cells must be in contact with a solid surface to divide

Density-dependent inhibition

When crowded cells stop dividing

Mutagen

Substance that causes mutations

Tumor

Abnormal cell mass

Benign tumor

Remains at its original site

Malignant tumor

Spreads into neighboring tissues and other parts of the body

Metastasis

Spread of a tumor through the bloodstream and circulatory system

Tumor suppressor

Protein that prevents the cell from moving to the next step in the cell cycle if they discover damage and can trigger apoptosis

Gene

Segment of a chromosome that codes for a specific characteristic

Karyotype

Picture of all the chromosomes in a cell with homologous chromosomes paired up and pairs lined up in height order and numbered

Haploid

Cell that contains a single set (half the number) of chromosomes

Diploid

Cell that contains two sets (the full number) of chromosomes

Somatic cells

Body cells

Gametes

Sex cells

Fertilization

The combination of two gametes

Zygote

Diploid cell formed by fertilization

Tetrad

Paired homologous chromosomes

Synapsis

Process of chromosomes pairing up to form tetrads

Recombination (crossing over)

Exchange of genetic material between chromosomes in a tetrad

Sperm

Male gamete

Egg

Female gamete

Polar body

Haploid cell that is formed alongside the egg but cannot be fertilized

Independent assortment

Random arrangement of chromosomes during metaphase