Cell Biology: Checkpoints in Mitosis

Questions and Answers

What is the primary function of the apoptotic checkpoint after the G2 phase?

To check for cell damage (correct)

To ensure DNA is correctly made

To align chromosomes

To initiate mitosis

The spindle assembly checkpoint occurs during anaphase.

False

What happens during prophase in mitosis?

The chromosomes coil, thicken, and the nuclear envelope breaks down

The space between sister chromatids is called a __________.

furrow Signup and view all the answers

Match the following checkpoints with their functions:

Apoptosis checkpoint = Checks if the cell is damaged Spindle assembly checkpoint = Ensures chromosomes are aligned G1 checkpoint = Checks if DNA is correctly made Metaphase checkpoint = Monitors spindle attachment Signup and view all the answers

What is the primary composition of microtubules?

Tubulin Signup and view all the answers

Microfilaments are long, thin rods composed of many molecules of tubulin.

False Signup and view all the answers

What role does the plasma membrane play in cellular communication?

The plasma membrane enables cellular communication by detecting signals and orchestrating responses. Signup and view all the answers

Microtubules are considered __________ because they are water-fearing.

hydrophobic Signup and view all the answers

Match the following cytoskeletal elements to their characteristics:

Microtubules = Long, hollow structures providing cellular movement Microfilaments = Thin rods composed of actin Intermediate Filaments = Provide structural support and stability Plasma Membrane = Facilitates cell-to-cell communication Signup and view all the answers

Study Notes

Cell Cycle Checkpoints

Furrow represents space between sister chromatids during cell division.
Apoptosis checkpoint in G2 phase ensures cells are not damaged; damaged cells undergo programmed cell death.
Spindle assembly checkpoint during metaphase verifies chromosome attachment and alignment to spindle apparatus.

Mitosis Overview

Prophase marks the first stage of mitosis, during which chromosomes coil, shorten, and thicken for easier separation.
Spindle fibers assemble, centrioles appear, and the nuclear envelope breaks down, setting the stage for further mitotic processes.

Mammalian Cells and Cytoskeleton

Mammalian cells in culture involve hydrophobic microtubules made of tubulin, enabling various cellular movements.
Microfilaments, composed of actin, help form a structural framework and aid in cellular functions.
Intermediate filaments provide structural stability, particularly abundant in nerve and skin cells.

Plasma Membrane Functions

The plasma membrane aids in cellular communication via signal transduction, detecting and transmitting signals.
Cellular adhesion is crucial for self-renewal processes leading to differentiation and tissue repair.

Bacterial Overview

Bacteria are the most prevalent organisms on Earth, characterized as single-celled prokaryotes lacking a nucleus.

Differences Between Cell Types

Prokaryotic cells lack organelles and a defined nucleus; eukaryotic cells contain organelles that perform specialized functions.
Nucleus is a double-membraned structure containing DNA and RNA, crucial for cellular function and gene expression.

Major Macromolecules

Carbohydrates, lipids, and proteins are essential macromolecules comprising cell structure and serving as energy sources.
Carbohydrates provide energy and support structural integrity.
Lipids are key components of membranes, hormones, and energy storage.
Proteins function in various roles, including enzymatic activity and immune response.

Smooth Endoplasmic Reticulum (ER)

Smooth ER is vital for protein synthesis, lipid synthesis, and acts as a quality control center for cellular processes.

Exosomes

Exosomes are vesicles involved in intercellular transport, facilitating communication by carrying proteins, lipids, and RNA.
They are approximately 30-100 nanometers in diameter and play a role in immune response management.

Intracellular Digestion

Faulty signal transduction or cellular adhesion can lead to health issues such as cancer, characterized by abnormal cell adhesion and invasion of healthy tissues.

Cytoskeleton Structure

The cytoskeleton is a meshwork of proteins providing structural support, cell shape, and positioning.
Consists of dynamic proteins that can be regularly broken down and rebuilt according to cellular activity.

Programmed Cell Death (Apoptosis)

Apoptosis, translated as "leaves falling from a tree," is a regulated process crucial for development and maintenance.
It works in synchrony with mitosis, ensuring the equitable distribution of chromosomes to daughter cells.

Description

Explore the crucial check points in the cell cycle, focusing on the furrow between sister chromatids and the apoptosis checkpoint after the G2 phase. This quiz will test your understanding of how cells ensure their DNA is correctly made and not damaged. Perfect for students studying cell biology.