What is the process of diffusion?
Movement of molecules from an area of higher concentration to an area of lower concentration
Diffusion is a passive transport mechanism.
What is osmosis?
Diffusion of water across a selectively permeable membrane
Osmosis specifically refers to water movement.
What is passive transport?
Movement of substances across a cell membrane without the use of energy
Examples include diffusion and osmosis.
What is active transport?
Movement of substances against their concentration gradient, requiring energy
Active transport often involves the use of ATP.
Define transcytosis.
A process that involves the transport of material across a cell via vesicles
Transcytosis combines endocytosis and exocytosis.
What is exocytosis?
The process of vesicles fusing with the plasma membrane to release their contents outside the cell
Commonly used to secrete hormones and neurotransmitters.
What is endocytosis?
The process of taking material into the cell by engulfing it in a vesicle
Includes phagocytosis and pinocytosis.
Differentiate between phagocytosis and pinocytosis.
Phagocytosis is the uptake of large particles; pinocytosis is the uptake of fluids and small molecules
Both are forms of endocytosis.
What is an isotonic solution?
A solution with the same solute concentration as the cell’s cytoplasm
Cells remain stable in isotonic solutions.
What is a hypertonic solution?
A solution with a higher solute concentration than the cell’s cytoplasm
Cells lose water and may shrivel in hypertonic solutions.
What is a hypotonic solution?
A solution with a lower solute concentration than the cell’s cytoplasm
Cells gain water and may burst in hypotonic solutions.
What are the four tenets of cell theory?
- All living organisms are composed of cells
- The cell is the basic unit of life
- All cells arise from pre-existing cells
- Cells contain hereditary information
Cell theory is fundamental to biology.
What are the general features and functions of the plasma membrane?
- Protects the cell
- Regulates transport
- Facilitates communication
- Maintains homeostasis
The plasma membrane is selectively permeable.
Differentiate between apoptosis and necrosis.
Apoptosis is programmed cell death; necrosis is uncontrolled cell death due to injury
Apoptosis is a normal physiological process.
What is the basic structure of DNA?
Composed of nucleotides, each containing a phosphate group, a sugar, and a nitrogenous base
DNA bases include adenine, thymine, cytosine, and guanine.
What is the basic structure of RNA?
Composed of nucleotides with a ribose sugar and uracil instead of thymine
RNA is usually single-stranded.
What is the central dogma of molecular biology?
The process of DNA -> RNA -> Protein
It describes the flow of genetic information.
What occurs during replication?
The process of copying DNA to produce two identical DNA molecules
Replication is essential for cell division.
What occurs during transcription?
The process of synthesizing RNA from a DNA template
Transcription occurs in the nucleus.
What occurs during translation?
The process of synthesizing proteins from mRNA at the ribosome
Translation involves tRNA and ribosomal subunits.
List the four phases of the cell cycle.
- G1 phase
- S phase
- G2 phase
- M phase
G0 phase is a resting state outside the cycle.
What are the three layers of the skin?
- Epidermis
- Dermis
- Hypodermis
Each layer has distinct functions and characteristics.
What are keratinocytes?
Cells that produce keratin, a key protein in the skin
Keratinocytes help protect the skin.
What are melanocytes?
Cells that produce melanin, responsible for skin pigmentation
Melanin protects against UV radiation.
