Chapter 3 - Cells Flashcards
Cells
- The basic unit of structure and function of all living things
- Has a cell or plasma membrane, and a nucleus
Nucleus
• Most important organelle within the cell
<ins>Function</ins>
• Control the activities of the cell & facilitate cell division
• DNA and chromatin
• Chromosomes
Nuclear membrane or nuclear envelope
Regulates transport of substances into & out of the cell
Nucleoplasm
A clear, semi-liquid medium that fills the spaces around the chromatin and the nucleoli
Nucleolus
Reservoir for RNA
Ribosomes
Serve as site for protein synthesis
Cytoplasm
Provides an organized watery environment where life
functions take place via the activities of the organelles,
which reside there
Centrosome
Contains two centrioles that are functional during animal cell division
Endoplasmic reticulum
Provides passage for the transport of substances in the cytoplasm
Mitochondria
- Serve as sites of cellular respiration & energy production
- Store ATP
Golgi apparatus
Manufactures carbohydrates and packages secretions for discharge from the cell
Lysosomes
Serve as center for cellular digestion
Perioxisomes
Enzymes that oxidize cell substances
Cytoskeleton
Forms internal framework
Pinocytic vesicles
Provide mechanism by which large molecules can enter the cell
Cilia and flagella
Create movement
Cellular Metabolism
• Chemical reactions occur within the cells<br></br>• Energy supplied by ATP<br></br>• ATP created from CHO, proteins, and fats that we eat
Cell Division
Meiosis & Mitosis
Meiosis
- Involves reproduction
- Process of cell division of the sex cell or gamete
- Ovum and spermatozoa reduce chromosomes from 46 to 23
- Fertilization
- Zygote is formed from two sex cells to obtain full set of 46 chromosomes
Mitosis
• Involves growth and maintenance of cells<br></br>
<ins>Cell division</ins>
• Division of the nucleus
• Division of the cytoplasm
Mitosis Stages
<ins>Phase I</ins> • Interphase (resting stage) <ins>Phase II</ins> • Prophase <ins>Phase III</ins> • Metaphase <ins>Phase IV</ins> • Anaphase <ins>Phase V</ins> • Telophase <ins>Cycle back to interphase</ins>
Cell Death
- Necrosis
* Apoptosis
Stem Cells
- Embryonic stem cells
- Adult stem cells
- Umbilical cord blood stem cells
- Induced pluripotent stem cells
Protein Synthesis
- Cells produce proteins
- DNA
- RNA
Movement of Materials Across Cell Membranes
- Passive transport
* Active transport
Passive transport
- Does not require an energy source
- Diffusion
- Osmosis
- Filtration
Active transport
- Requires an energy source
- Phagocytosis
- Pinocytosis
Specialization
- Nerve cells
- Red blood cells
- May lose some functions, such as reproduction
- Interdependence among cells
Nerve Cells (Specialization)
• Specialize in response
Red Blood Cells (Specialization)
• Specialize in oxygen transport
Aging
- Aging is a phase of normal development
- Older person may have 30% fewer cells
- Cells may change in ability to perform specialized tasks
- Physiologic changes are universal & progressive
- Aging is not a disease
Disorders of Cell Structure
- Atrophy
- Hypertrophy
- Hyperplasia
- Metaplasia
- Dysplasia
- Neoplasia
Tumor
- When cell division does not occur in the usual pattern
- Also called neoplasms
- Benign tumors
- Malignant tumors
Necrosis
- The unprogrammed death of cells and living tissue
- Cells that die from necrosis may release harmful chemicals that damage other cells
<ins>◊ Causes:</ins> • Injury • Infection • Cancer • Infarction (blood clot) • Toxins • Inflammation
Apoptosis
• An orderly process by which cells intentionally die