Cell Biology Lecture 2 Flashcards
The Cytoplasm Overview
Definition, Components
Definition: The region between the plasma membrane and nucleus.
Components: Cytosol and Organelles.
Cytosol
Definition, Composition, Function
Definition: Fluid portion of cytoplasm.
Composition: 55% of cell volume, mainly water (70%-90%), and dissolved solutes.
Function: Major site for chemical reactions in the cell.
Organelles
Definition, Function
Definition: Specialized structures, often termed “little organs.”
Function: Contribute to overall cellular functioning and metabolic processes
Cytoskeleton Overview
Definition, Types
Definition: Cellular components determining cell shape and structure.
Types: Microfilaments, Intermediate Filaments, Microtubules.
Microfilaments
Definition, Composition, Functions
Definition: Smallest cytoskeleton structures.
Composition: Primarily actin protein.
Functions: Movement, support, cytokinesis, muscle contraction, anchor to cell membrane, microvilli formation.
Intermediate Filaments
Defintion, Functions
Definition: Medium-sized structures made of various proteins, including keratin.
Functions: Internal stability, organelle positioning, cell junction support.
Microtubules
Definition, Structure, Functions
Definition: Largest cytoskeleton structures mainly composed of tubulin protein.
Structure: Long, hollow tubes produced in the centrosome.
Functions: Determine cell shape, facilitate organelle and chromosome movement, form external structures like cilia and flagellum.
Centrosome
Definition, Components, Functions
Definition: Microtubule organizing center.
Components: Centrioles (cylindrical structures), pericentriolar material.
Functions: Involved in mitosis/meiosis, starting point for mitotic spindles.
Cilia
Definition, Functions
Definition: Hair-like projections for cell mobility.
Functions: Coordination in movement (e.g., egg cells), sweeping foreign particles (e.g., respiratory tract).
Flagella
Definition, Location
Definition: Long, whip-like structures for cell propulsion.
Location: Found in sperm cells.
Ribosomes
Definition, Location, Composition
Definition: Responsible for protein synthesis (translation).
Location: Free-floating (cytosol) or attached to endoplasmic reticulum.
Composition: 2 subunits of ribosomal RNA (rRNA).
Endoplasmic Reticulum (ER)
Definition, Types
Definition: Network of tubules or sacs extending from the nuclear membrane.
Types: Smooth ER (lipid production, detoxification), Rough ER (ribosomes, protein synthesis).
Golgi Complex/Apparatus/Body (GB)
Functions, Structure
Functions: Receives, transports, and modifies proteins from rough ER.
Structure: Three sacs - entry/cis face, medial cisternae, exit/trans face.
Vesicles
Definition, Examples
Definition: Compartments formed by lipid bilayer.
Examples: Lysosomes (digestive enzymes), Peroxisomes (digestive proteins, detoxification), Secretory Vesicles (transport materials for exocytosis).
Mitochondria
Definition, Structure, Unique Features
Definition: Powerhouse of the cell, generates ATP through aerobic metabolism.
Structure: Outer and inner membrane, cristae folds in the matrix.
Unique Features: Self-replicating, contains own DNA (maternal inheritance).
Nucleus
Definition, Structure, Components
Definition: The brain of the cell, responsible for genetics and protein synthesis.
Structure: Double membrane (nuclear envelope) with pores.
Components: Nucleolus (makes rRNA), Genetic Material (DNA, genes, chromosomes).
DNA Structure
Description, Components, Bonding
Description: Double-stranded helix.
Components: Alternating pentose sugars and phosphate group.
Bonding: Complementary nitrogenous base pairs form hydrogen bonds.
DNA Length
Insight, Fact
Insight: Stretched DNA in one cell = 6 feet.
Fact: Stretched DNA in the human body = 108 billion km (equal to 150,000 round trips to the Moon).
Genes
Definition, Purpose, Quantity
Definition: Segments of DNA encoding specific traits.
Purpose: Code for proteins influencing structure, function, appearance.
Quantity: Approximately 20,000 genes in the human genome.
Alleles
Explanation, Examples, Genetic Makeup, Observable Traits
Explanation: Normal DNA sequence variation at a genomic location.
Examples: Alleles for hair color (red, blonde, brown).
Genetic Makeup: Genotype (base pair sequence).
Observable Traits: Phenotype.
Histones and Nucleosomes
Definitions + Linker DNA
Histones: Protein balls around which DNA double helix coils.
Nucleosomes: Combination of histones and clusters of double-stranded DNA.
Linker DNA: Section linking nucleosomes together.
Chromatin
Definition, State
Definition: DNA, RNA, & proteins scattered before cell division.
State: Appears diffuse and granular, clusters to form chromosomes during division.
Chromosomes and Chromatids
Chromosomes, Homologous Chromosomes, Chromatids, Centromere
Chromosomes: Arrangement of chromatin fibers during cell division.
Homologous Chromosomes: Form pairs (1-22 autosomal, 23 sex chromosomes).
Chromatids: Half of a chromosome; 1 pair = 1 chromosome.
Centromere: Central portion holding chromatids or sister chromatids together.
Telomeres
Description, Function, Consequence
Description: Non-coding, repeated units at chromosome ends.
Function: Protect ends, prevent loss during cell division.
Consequence: Shorter telomeres associated with diseases, poor survival, aging.
Genome
Definition, HGP, Progress
Definition: Total genetic information in the nucleus.
Human Genome Project (HGP): Completed in 2003, mapped much of the genome.
Progress: In 2022, genome almost completely mapped.
Genome and Intelligence
Insight, Example
Insight: Number of genes does not correlate with intelligence.
Example: Some plants have more genes than humans, challenging traditional assumptions.
