Cell Theory: Prokaryotic and Eukaryotic Cells
Principles of Cell Theory
- Cells are the basic unit of living things.
- Every cell comes from another cell.
- Preexisting cells transmit information from one generation to another.
Prokaryotic Cells
Unicellular, prokaryotic DNA is dispersed in the cytoplasm. They have no organelles except for ribosomes, a cell wall, and a plasma membrane that folds. Some have flagella.
Structures:
- Plasma membrane
- Ribosomal DNA
- Cell wall
- Cytoplasm
- Flagella
Eukaryotic Cells
Eukaryotic cells can be unicellular or multicellular. They
Read MoreHomeostasis, Osmoregulation, Growth, and Reproduction in Organisms
Homeostasis
Homeostasis is the maintenance of relatively stable internal conditions despite changes in the external environment. In humans, the hypothalamus checks the current temperature to match the normal 37°C.
Enzyme Activity
For every 10°C rise in temperature, enzyme activity doubles.
Heat Exchange Equation
Hs = Hm + Hcd + Hcv + Hr – He
- s (stored heat in the body)
- m (metabolism)
- cd (conduction)
- cv (convection)
- r (radiation)
- e (evaporation)
Variation in Body Temperature
- Poikilotherms: Body temperature
Natural Selection and the Evolution of Species
**Natural Selection**
- Over time, populations with traits less suited to the environment will decrease.
- Organisms best adapted to their environment will thrive.
- Giraffe Example: Giraffes with longer necks can reach higher leaves, giving them an advantage.
- Accumulated changes over generations can lead to the formation of new species.
**Neo-Darwinism – Synthetic Theory**
Neo-Darwinism rejects Lamarckism. The unit of evolution is the population, not individuals. Genetic mutations and natural selection drive
Read MoreGenetic Concepts and DNA Technology: A Comprehensive Overview
Key Genetic Terms and Concepts
Locus: The physical location of a gene on a chromosome.
Allele: Different versions of a given gene. New alleles form because of mutations, changes in the DNA. Mutations can be:
- Neutral (most of the time)
- Harmful (sometimes)
- Beneficial (occasionally)
Genotype: The combination of alleles an organism has.
Phenotype: The combination of alleles that create a physical trait.
Homozygous: If the alleles at a given locus are the same.
Heterozygous: If the alleles at a given locus are
Read MoreUniverse, Solar System, Earth, and Life: Key Concepts
The Universe
The universe encompasses all matter, energy, space, and time. Everything that exists is part of it. Matter in the universe is not destroyed but is uniformly distributed in places known as galaxies. Galaxies consist of matter that does not emit light (dark matter) and has gravitational attraction.
Location of Earth
Galaxies are large accumulations of matter in the form of dark matter and visible matter. The latter is formed by stars, nebulae, and dust. Our galaxy has millions of stars forming
Read MoreHospital Patient Data: Vital Signs, Fluid Balance & Charts
Identifying Patient Data
This section outlines the key components of patient data typically found in hospital records:
- Patient Identification: This may include an anagram of the patient’s name, unit, and identification number.
- Hospitalization Details: Month, year, date, or day of hospitalization.
- Allergies: A record of any known patient allergies.
Representation of Vital Signs
Vital signs are crucial indicators of a patient’s health status. They are typically represented graphically and include:
- Respiration