BSC 2085 Lab 2 Flashcards: The Cell Cycle, Membrane Transport, Integumentary System

A comprehensive set of Q&A style flashcards covering the cell cycle, membrane transport, and the integumentary system as presented in the notes.

What is the cell cycle?

The period from when a cell is formed to when it divides, including interphase (G1, S, G2) and the mitotic phase.

Which phases comprise Interphase?

G1, S, and G2 phases.

Which cells stay in G0 and do not pass G1?

Neurons and skeletal muscle cells.

What happens during G1?

Cell growth, replication of centrioles, and size increase; duration varies.

What happens during S phase?

DNA replication.

What happens during G2?

Growth and preparation for mitosis; centriole replication completed.

List the stages of mitosis.

Prophase, Metaphase, Anaphase, Telophase.

What occurs in Prophase?

DNA condenses into chromosomes (about 92 chromatids), the nuclear envelope disintegrates, centrioles move to poles, and spindle fibers attach to centromeres.

What occurs in Metaphase?

Chromosomes align along the cell’s equator.

What occurs in Anaphase?

Sister chromatids are pulled to opposite poles by spindle fibers.

What occurs in Telophase?

Nuclear envelope reforms; spindle fibers disassemble; chromosomes decondense.

What is cytokinesis?

Division of the cytoplasm; in animal cells a cleavage furrow forms to split the cell, while in plant cells a cell plate forms to separate the cells.

What is the cleavage furrow?

An inward membrane indentation formed during cytokinesis by a contractile actin ring to pinch the cell membrane and divide the cell.

What is the major component of cell membranes?

Phospholipids; the cell membrane is a phospholipid bilayer and is selectively permeable.

What is diffusion?

Passive transport where solutes move down their concentration gradient until equilibrium; no energy required.

What is facilitated diffusion?

Diffusion that requires channel or carrier proteins for larger or lipid-insoluble solutes.

What is osmosis?

Diffusion of water across a selectively permeable membrane from regions of lower solute concentration to higher.

What is tonicity?

The ability of a solution to cause a cell to gain or lose water.

Define isotonic solution.

Solute concentration is equal outside and inside the cell; no net water movement.

Define hypertonic solution.

Solute concentration is higher outside the cell; water leaves the cell and it shrinks.

Define hypotonic solution.

Solute concentration is lower outside the cell; water enters the cell and it swells or bursts.

What is osmoregulation?

Regulation of water balance in organisms to prevent osmotic problems.

What is the sodium-potassium pump?

An active transport pump that uses ATP to move Na+ out and K+ in, maintaining cellular gradients.

What are endocytosis and exocytosis?

Energy-requiring processes for bulk transport; endocytosis brings materials into the cell, exocytosis exports materials.

What is phagocytosis?

A form of endocytosis where the cell engulfs solid particles into a food vacuole and digests them in lysosomes.

What is pinocytosis?

A form of endocytosis where the cell ingests extracellular fluid into small vesicles.

What is the difference between diffusion and osmosis?

Diffusion moves solutes down their concentration gradient; osmosis is water movement across a membrane.

What is the epidermis?

The outer, protective layer of the skin made of stratified squamous epithelium.

What are the four epidermal strata in order from base to surface?

Stratum basale, stratum spinosum, stratum granulosum, stratum corneum (and stratum lucidum in thick skin).

What cells reside in the epidermis?

Melanocytes, keratinocytes, Langerhans’ cells, Merkel cells, and basal cells.

What is the function of melanocytes?

Produce melanin to protect skin from UV light.

What is the role of basal cells in the epidermis?

Basal cells divide in the basale layer; one daughter remains, the other is pushed upward.

What is the stratum spinosum known for?

8–10 layers; lower layers divide and upper layers produce keratin.

What is the stratum granulosum?

3–5 layers; keratinization begins; cells become dehydrated and die.

What is the stratum corneum?

15–30 layers of dead, keratin-filled cells; outer protective layer renewed every weeks.

What is the stratum lucidum?

A thin, clear layer present only in thick skin (palms and soles).

What are dermal papillae?

Projections of the dermis into the epidermis in the papillary layer, containing capillaries.

What are Meissner’s and Pacinian corpuscles?

Meissner’s respond to light touch; Pacinian respond to deep pressure and vibration.

What are sebaceous glands?

Oil-secreting glands that produce sebum; linked to hair follicles; not on palms/soles.

What are sudoriferous glands and their two types?

Sweat glands; eccrine (water and salts) are widespread; apocrine are thicker and found in axillae/genital areas.

What is the function of hair in the integumentary system?

Hair grows from follicles; produced by epidermal cells; provides protection and sensation.

What is the hypodermis?

Subcutaneous layer of adipose and areolar tissue; anchors skin to underlying tissues and is not part of the integument.

What is the dermis composed of and what does it contain?

Dense connective tissue with the papillary and reticular layers; houses blood vessels, nerves, glands, and hair follicles.

Where are tactile cells located?

Merkel cells in the epidermis associated with sensory nerve endings for touch.

What is the role of the epidermal barrier?

Provides protection and water resistance against mechanical, chemical, and bacterial damage.