Cell Communication & The Cell Cycle

Autocrine

type of cellular signaling where a cell signals itself

Juxticrine

type of cellular signaling where a cell signals cells next to it

Paracrine

type of cellular signaling where a cell signals cells over short distances/gaps

Endocrine

type of cellular signaling where the cells transmit signals through the bloodstream to other cells around the body

3 stages of Signal Transduction Pathways

1) reception

2) transduction

3) response

Signal Transduction Stage 1: Reception

detection of a signal molecule coming from outside the cell

Signal Transduction Stage 2: Transduction

converting signal to a form that can bring about a cellular response

Signal Transduction Stage 3: Response

a specific cellular response to the signal molecule

Phosphorylation Cascade

adding a phosphate group to something to enhance and/or amplify a signal

Results of a Signal Transduction Pathway

1) genes being turned on/off

2) enzyme activates

3) apoptosis

ligand

chemical messenger

quorum sensing

a signal mechanism used by bacteria to detect changes in their population density to create a response to their environment

negative feedback

returns a system to homeostasis if the system is disrupted

positive feedback

amplification of a response to move a variable further away from the initial set point to disrupt homeostasis

Cell Cycle Parts

1) Interphase

2) M-Phase

Stages of Interphase

1) G₁

2) S

3) G₂

Stage 1 of Interphase: G₁

cell growth

Stage 2 of Interphase: S

copies of DNA are made

Stage 3 of Interphase: G₂

cytoplasmic components are doubled in preparation for division

Stages of M-Phase

1) Mitosis

2) Cytokinesis

Stages of Mitosis

1) Prophase

2) Metaphase

3) Anaphase

4) Telophase

Stage 1 of Mitosis: Prophase

• nuclear envelope begins to disappear

• DNA coils into visible chromosomes

• fibers begin to move double chromosome toward the center of the cell

Stage 2 of Mitosis: Metaphase

• fibers align double chromosomes across the center of the cell

Stage 3 of Mitosis: Anaphase

• fibers separate double chromosomes into single chromosomes(chromatids)

• chromosomes separate at the centromere

• chromatids migrate to opposite side of the cell

Stage 4 of Mitosis: Telophase

• nuclear envelope reappears and established 2 separate nuclei

• each nucleus contains a complete set of information in the cell(genome)

• chromosomes will begin to uncoil

Cytokinesis

• separates the cells into 2 daughter cells, each containing identical genomes

• equal distribution of cytoplasm to both daughter cells

Checkpoints of The Cell Cycle

1) G₁ Checkpoint

2) G₂ Checkpoint

3) M-spindle Checkpoint

Checkpoint #1 of The Cell Cycle: G₁ Checkpoint

• at the end of the G₁ phase

• checks cell size

• checks nutrients

• checks growth factor

• checks DNA damage

Checkpoint #2 of The Cell Cycle: G₂ Checkpoint

• at the end of the G₂ phase

• checks DNA replication

• checks DNA damage

Checkpoint #3 of The Cell Cycle: M-spindle Checkpoint

• fiber attachment to chromosome check