wk2: formative quiz - cells & tissue

These flashcards cover key concepts related to the cell cycle, cell signaling, plasma membrane functions, and cell structure.

What is the primary function of cell cycle checkpoints?

To ensure accurate DNA replication and division.

How do gases move through the plasma membrane?

Gases move through the plasma membrane via simple diffusion.

What is the result of a mutation in a G-protein coupled receptor (GPCR) that prevents G-protein binding?

A failure to activate downstream signalling.

What are the types of adaptive functions of a cell?

Atrophy, hypertrophy, hyperplasia, metaplasia, dysplasia, and neoplasia.

Which is NOT a characteristic of necrosis?

Absence of an inflammatory response.

What are some characteristics of necrosis?

Repture of the cell membrane, cellular swelling, organelle swelling, significant inflammatory response.

What is metaplasia?

Metaplasia is the transformation of one cell type into another type in response to environmental changes or stressors.

What is hyperplasia?

Hyperplasia is the increase in cell numbers resulting from proliferation in response to increased demand or an inflammatory response.

What is hypertrophy?

Hypertrophy is an increase in cell size due to increased demand from the accumulation of new proteins and organelles. Ocurs when cells cannot divide.

What is atrophy?

Atrophy is the decrease in cell size caused by loss of organelles, cytoplasm and proteins. Atrophy can be caused by inactivity, malnutrition, aging and genetic factors.

What is dysplasia?

Dysplasia is an increase in the number of abnormal/unequal cells. Cells become disorganised and lose function. Pre-cancerous, though mild/moderate, can be reversible.

What is neoplasia?

Neoplasia is an irreversible transformation of cells into cancerous cells. Neoplasia cells grow uncontrollably and can invade other tissues.

What is the sequence of cancerous cells being formed?

Hyperplasia, dysplasia, and neoplasia under persistent stress.

What order is the cell cycle?

Interphase, mitosis, cytokinesis.

What is occurring at interphase?

Cells performing normally, not focused on division but preparing for it, can remain here indefinitely.

In what order does interphase occur?

G0, G1 phase, S phase, G2 phase.

In what order does Mitosis occur?

Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.

What is occurring at mitosis?

Cell division occurs, and identical copies of DNA are generated.

What occurs during cytokinesis?

Physical separation into two daughter cells.

What occurs at the G0 phase?

Normal cell function, and the cell is not preparing for division.

What occurs in the G1 phase?

Generation of organelles, preparing for division.

What occurs at the G1 checkpoint?

Assessment of conditions for cell division. (size, nutrient availability, and DNA integrity)

What happens if conditions at the G1 checkpoint aren’t met?

The cell enters G0 phase, halting division until conditions improve.

What occurs in the S phase?

Duplication of chromosomes, DNA replication in preparation for cell division, synthesis of histones and nuclear proteins.

What occurs in the G2 phase?

Final phase before mitosis, final protein synthesis, and centriole replication.

What occurs at G2 checkpoint?

Checks if DNA has been replicated correctly, and if the pre-mitotic cell is a suitable size for division.

What occurs if G2 checkpoint fails?

The cell will undergo arrest or apoptosis.

What does the M checkpoint ensure?

If chromatids are properly attached to spindle microtubules, to determine if the chromosomes will be evenly divided between daughter cells before anaphase begins.

What occurs if the M checkpoint fails?

The cell will undergo apoptosis.

Which phase of the cell cycle immediately precedes mitosis?

G2 phase.

What phases does mitosis go through, in order?

Early Prophase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis.

What occurs during early prophase?

Chromosomes condense and become visible, spindle fibres emerge from centrosomes, and the nuclear membrane disappears.

What occurs during prophase?

Chromosomes continue to condense, spindle fibres capture and organise chromosomes, and centrosomes migrate to opposite sides of the cell.

What occurs during metaphase?

Chromosomes align along the centre of the cell, and each sister chromatid is attached to microtubules at opposite poles.

What occurs during anaphase?

Centromeres split in two, microtubules pull the chromatids away from centre, and spindle fibres begin to elongate the cell.

What occurs during telophase?

Nuclear membranes reform around each set of chromosomes to form two new nuclei, spindle fibres continue to push the poles apart, chromosomes begin to decondense and uncoil.

What occurs during cytokinesis?

Division of the cytoplasm to form two daughter cells, a ring of actin protein pinches the cell along the central crease (cleavage furrow) to divide the cytoplasm equally.

During which phase of cell division do chromosomes uncoil, the nuclear membrane forms, and cytokinesis occurs?

Telophase.

How does water pass through the plasma membrane?

Through osmosis or via aquaporins.

What is osmosis?

Diffusion of water across a membrane that maintains similar solute concentrations between the intracellular and extracellular environments.

What do receptor molecules on the surface of a cell bind to?

Ligands

What is a ligand?

A molecule that binds to a specific receptor on a cell's surface, triggering a response.

Which is NOT a function of plasma membrane proteins?

Serving as nutrients for the cell.

What are some functions of a plasma membrane PROTEINS?

Act as a carrier molecule for various solutes, binding to ligands to initiate signalling pathways, regulating the passage of water and small solutes into/out of the cell, and acting as an anchor for the cell membrane.

During which phase of mitosis do chromatids separate into daughter chromosomes?

Anaphase.

Which cellular change is reversible?

Atrophy, hyperplasia, hypertrophy, metaplasia, and dysplasia.

What are the four main modes of cellular communication?

Autocrine, Paracrine, Endocrine, and contact-dependent.

What occurs during autocrine signaling?

Self-signalling, where ligands bind to receptors on the same cell.

What occurs during paracrine signaling?

Short-distance communication between neighbouring target cells. Ligand diffuses across the extracellular space. Induces quick and short-lasting responses.

What occurs during endocrine signaling?

Long-distance communication where hormones are released into the bloodstream to affect distant target cells.

What is the process of dividing the cytoplasm of a cell into two daughter cells?

Cytokinesis.

What describes necrosis?

Accidental/traumatic cell death resulting from injury or disease, leading to inflammation.

What describes Apoptosis?

Programmed cell death that occurs in a controlled, regulated manner, allowing for the removal of unwanted or damaged cells without causing inflammation.

What is a chromatid?

Half of a replicated chromosome.

What is a centromere?

The site where sister chromatids connect. to each other.

What is a chromatin?

The substance of chromosomes made up of DNA and protein.

What is a chromosome?

An organised package of DNA found in the nucleus.

During which phase of the cell cycle does the cell grow and carry out its normal metabolic functions?

Interphase, specifically the G1 phase.

What is the longest phase of the cell cycle?

Interphase.

Which of the following cytoskeleton components moves the chromosomes during cell division?

Microtubles

What is the sequence of events that occur when a receptor ion channel is activated?

The ligand binds to the ion channel, ion channel changes shape, ions flow in/out of the cell, a cellular response is induced.

What is an example of passive transport?

Passive transport requires no energy, such as osmosis.

What is an example of active transport?

Active transport requires energy and is used when substances are carried or moved against their concentration gradient.

What mechanism allows small and medium-sized charged particles to pass through the plasma membrane?

Facilitated diffusion through non-specific and specific transporters.

What does facilitated diffusion mean, and what are the two types?

Facilitated diffusion is a type of passive transport that allows substances to cross membranes with the assistance of special transport proteins. The two types are non-specific (channel proteins) and specific transporters (carrier proteins).

What is the enlargement of cardiac muscle cells due to increased workload called?

Hypertrophy.

What is the process called when a defense cell engulfs a bacterium?

Phagocytosis, a type of endocytosis.

Which process transports materials from the cell into the extracellular fluid?

Exocytosis.

What is a centrosome?

The cell’s division organiser, containing two centrioles, which duplicate before cell division and move to opposite sides of the cell.

What are centrioles?

Cylindrical microtubule structures found in pairs inside the centrosome that must replicate before cell division so each new daughter cell receives its own set.

What are spindle fibres?

Microtubule strands produced by the centrosomes that stretch across the cell during division, physically grabbing and pulling chromosomes to opposite ends of the cell during anaphase.

What is p53?

Guardian of the genome that acts as a tumour suppressor and regulates cell division. p53 stops cells with damaged or mutated DNA from dividing and arrests cell growth at the G1/S checkpoints.

What are receptor ion channels and how do they function?

A cell surface receptor that serves as an ion channel through the plasma membrane. Ion channels open or close in response to specific signaling molecules, allowing ions to flow in and out of the cell, thus influencing cellular activities.

What are enzyme-linked receptors and how do they function?

A receptor that directly activates an enzyme on the inside of the cell when a signalling molecule binds to the outside, triggering a chain of chemical reactions that alter cell behaviour

What are G-protein coupled receptors, and how do they function?

A cell surface receptor that is enzymatically linked to a G-protein. When the ligand binds, the GPCR changes shape, and the G-protein is activated. This sets off a cascade of events inside the cell that amplifies the original signal.

What are intracellular receptors and how do they function?

Receptors located inside the cell (in the cytoplasm or nucleus), activated by lipid-soluble signalling molecules that are able to pass directly through the plasma membrane, ultimately travelling to the nucleus to bind to DNA and alter transcription and translation.