Exam #4 Study Guide (Chapters 11-13)

A comprehensive set of vocabulary flashcards based on the lecture notes covering Chapters 11-13.

Requirements for cellular communication

Presence of signaling molecules, receptors, and target cells.

Three steps of cellular communication

Reception, transduction, response.

Three types of local signaling

Paracrine signaling, synaptic signaling, and autocrine signaling.

Long-distance signaling

Endocrine signaling involving hormones transported through the bloodstream.

Ligand

A signaling molecule that binds to a receptor and initiates a response.

Two major types of receptors

Cell surface receptors and intracellular receptors.

Three types of membrane receptors

G-protein coupled receptors, receptor tyrosine kinases, and ion channel receptors.

Signal transduction pathway

A series of molecular events and chemical reactions that lead to a cellular response.

Protein kinases

Enzymes that phosphorylate proteins, often activating them.

Phosphatases

Enzymes that remove phosphate groups from proteins, often deactivating them.

Phosphorylation cascade

A sequence of events where one protein kinase activates another, amplifying the signal.

Second messengers

Small molecules that propagate a signal inside the cell after receptor activation.

cAMP pathway

A signaling pathway involving cyclic AMP as a second messenger.

IP3/DAG pathway

A signaling pathway involving inositol trisphosphate and diacylglycerol as second messengers.

Signal amplification

The process by which a single signal can lead to a large cellular response.

Signal specificity

The ability of signaling pathways to elicit specific responses in target cells.

Signal efficiency

The effectiveness of the signal transmission and its biochemical interactions.

Signal termination

The process of stopping the signaling pathway to prevent overreaction.

Apoptosis

Programmed cell death, crucial for development and maintaining homeostasis.

Chromatid

One half of a duplicated chromosome, attached to its sister chromatid at the centromere.

Chromosome

A structure made of DNA and protein that contains genetic information.

Homologous chromosomes

Pairs of chromosomes that have the same structure but may carry different alleles.

Sister chromatids

Identical copies of a chromosome, joined at the centromere, formed during replication.

Somatic cell

Any cell of the body except sperm and egg cells, diploid in humans.

Gamete

A reproductive cell (sperm or egg), haploid in humans.

Cell division in prokaryotes

Binary fission.

Cell division in eukaryotes

Mitosis and meiosis.

Similarities between mitosis and meiosis

Both are processes of cell division that result in new cells.

Differences between mitosis and meiosis

Mitosis results in two genetically identical cells, whereas meiosis results in four genetically distinct cells.

Two major parts of the cell cycle

Interphase and mitotic phase.

Purpose of mitosis

To segregate duplicated chromosomes into two daughter cells.

Mitosis cell type

Used by somatic cells for growth and repair.

Events in G1 phase

Cell growth and preparation for DNA replication.

Events in S phase

DNA replication occurs.

Events in G2 phase

Preparation for mitosis; cell growth continues.

Prophase events

Chromatin condenses, nuclear envelope breaks down, spindle fibers form.

Prometaphase events

Chromosomes attach to spindle fibers via kinetochores.

Metaphase events

Chromosomes align at the metaphase plate.

Anaphase events

Sister chromatids are pulled apart to opposite ends of the cell.

Telophase events

Nuclear membranes reform, chromosomes de-condense.

Cytokinesis

Division of the cytoplasm into two daughter cells after mitosis.

Difference between mitosis and cytokinesis

Mitosis is the division of the nucleus, while cytokinesis is the division of the cytoplasm.

Daughter cells at end of mitosis

Two daughter cells, diploid.

Mitotic spindle

Structure composed of microtubules that helps segregate chromosomes.

Cytokinesis in animal cells

Cleavage furrow forms to separate the cells.

Cytokinesis in plant cells

Cell plate forms to divide the cells.

Three checkpoints of the cell cycle

G1 checkpoint, G2 checkpoint, and M checkpoint.

Questions at G1 checkpoint

Is the cell large enough? Is the DNA intact?

Questions at G2 checkpoint

Was DNA replicated correctly? Is the cell ready for mitosis?

Questions at M checkpoint

Are all chromosomes aligned properly?

Red light at a checkpoint

Cell cycle arrest or apoptosis.

Growth factors

Proteins that stimulate cell division.

Density-dependent inhibition

Cells stop dividing when they become too crowded.

Anchorage dependence

Cells must be attached to a substrate to divide.

Differences between cancer cells and normal cells

Cancer cells divide uncontrollably, ignore growth signals, and may invade other tissues.

Ways organisms can reproduce

Asexual and sexual reproduction.

Monoecious organi

Organisms that have both male and female reproductive structures.

Dioecious organisms

Organisms that have distinct male and female individuals.

Sexual life cycles in animals

Involves fertilization of gametes.

Sexual life cycles in plants

Alternation of generations between diploid and haploid stages.

Sexual life cycles in fungi

Also involves haploid and diploid stages, but predominantly haploid.

Differences between autosomes and sex chromosomes

Autosomes are non-sex chromosomes, while sex chromosomes determine sex.

Genetic designation for females

XX.

Genetic designation for males

XY.

Haploid cell definition

A cell with a single set of chromosomes.

Diploid cell definition

A cell with two sets of chromosomes.

Meiosis I events

Homologous chromosomes separate.

Meiosis II events

Sister chromatids separate.

Daughter cells at end of Meiosis I

Two daughter cells, haploid, genetically distinct.

Daughter cells at end of Meiosis II

Four daughter cells, haploid, genetically distinct.

Three unique events in meiosis

Crossing over, independent assortment, and random fertilization.

Significance of crossing over

Increases genetic diversity among offspring.

Chiasmata

Points where homologous chromosomes cross over during meiosis.

Synaptonemal complex

Structure formed between homologous chromosomes during meiosis.

Nondisjunction

Failure of chromosomes to separate properly during cell division.

Problems with nondisjunction

Can lead to conditions such as Down syndrome or Turner syndrome.