Baylor Bio 1305 Lopez: Exam 3

ligand

signaling molecule

Receptor protein

molecule to which the receptor binds (bind a limited number of ligands)

signal transduction

converts the information in the signal into a cellular response

intracellular receptors

Hydrophobic ligands, Can cross the membrane

Plasma membrane receptors

Hydrophilic ligands, Cannot cross the membrane

quorum sensing

A concentration of signaling molecules allows bacteria to sense local population density in a process called

Direct contact, Paracrine signaling, Synaptic signaling, Endocrine signaling

4 basic mechanisms for cellular communication

Signal reception

target cell detects a signaling molecule that binds to a receptor protein

Cellular response

the transduced signal triggers a specific response in the target cell

G protein-coupled receptors, Receptor tyrosine kinases, Ion channel receptors

There are three main types of membrane receptors

inactive, active

G proteins bind the energy-rich GTP

GDP bound =

GTP bound =

Receptor tyrosine kinases (RTKs)

are membrane receptors that catalyze the transfer of phosphate groups from ATP to another protein

ligand-gated ion channel receptor

acts as a gate that opens and closes when the receptor changes shape

cytoplasm or nucleus

Intracellular receptor proteins are found in the --------- of target cells

Protein phosphatases

rapidly remove phosphatesfrom proteins, a process called dephosphorylation

second messengers

These are small, nonprotein, water-soluble molecules or ions that spread throughout a cell by diffusion

Cyclic AMP (cAMP)

a small molecule produced from ATP, is one of the most widely used second messenger

Adenylyl cyclase

an enzyme in the plasma membrane, convertsATP to cAMP in response to an extracellular signal

Apoptosis

Cells that are infected, damaged, or at the end of their functional lives often undergo"programmed cell death"

Genome

All the DNA in a cell constitutes the cell's

chromosomes

DNA molecules in a cell are packaged into

Karyotype

Array of chromosomes of an individual

Gametes

(reproductive cells: sperm and eggs) have half as many chromosomes as somatic cells; they are haploid

somatic cells (body cells)

(nonreproductive cells) have two sets of chromosomes; they are diploid

chromatin

a complex of DNA and protein that condenses during cell division

centromere

is the narrow "waist" of chromosome, where the two chromatids are most closely attached

sister chromatids

Each duplicated chromosome has two --------- (joined copies of the original chromosome)

cytokinesis

the division of the cytoplasm

mitosis

the division of the genetic material in the nucleus

mitotic (M) phase (mitosis and cytokinesis)

interphase (cell growth and copying of chromosomes in preparation for cell division)

the cell cycle consists of

G1, S, G2

Interphase (about 90% of the cell cycle) can be divided into three phases

prophase, prometaphase, metaphase, anaphase, telophase

Mitosis is conventionally broken down into five stages

Malignant tumors

invade surrounding tissues and can undergo metastasis, the spread of cancer cells to other parts of the body, where they may form additional tumors

benign tumor

If abnormal cells remain only at the original site, the lumpis called a

Kinetochore

protein complex associated with centromeres

cyclins and cyclin-dependent kinases (Cdks)

What are the 2 types of regulatory proteins involved in cell cycle control?

locus

A gene's specific position along a chromosome is called its...

autosomes

What are the remaining 22 pairs of chromosomes in humans that are not sex chromosomes?

Homologous chromosomes

Meiosis I separates...

Sister chromatids

Meiosis II separates...

Prophase I

Where does crossing over occur?

Metaphase/Anaphase I

Where does random (independent) assortment

Independent assortment of chromosomes

Crossing over

Random fertilization

3 mechanisms that contribute to genetic variation?

Character (gene)

A heritable feature that varies among individuals

Law of segregation

Segregation corresponds to the distribution of homologous chromosomes to different gametes in meiosis

and

Multiplication rule needs the keyword...

or

Addition rule needs the keyword...

Complete dominance

Incomplete dominance

Codominance

What are the 3 degrees of dominance?

Pleiotropy

What property do we call genes that have multiple phenotypic effects?

Epistasis

When do we have 1 gene affecting the phenotype of another due to interaction of theirgene products?

Aneuploidy

What results from the fertilization of gametes in which nondisjunction has occurred?

Nondisjunction

When do pairs of homologous chromosomes or sister chromatids do not separateduring meiosis?

Polyploidy

When an organism has more than 2 complete sets of chromosomes, this is called...

Deletion

Removal of a chromosomal segment

Inversion

Reversing a segment within a chromosome

genomic imprinting

the phenotype depends on which parent passed along the alleles for those traits