Biology 151: Cell Structure and Function

• Biology 151 is an introductory biology course.
• It typically covers fundamental biological principles.
• Topics include cell structure and function, genetics, evolution, and ecology.
• The course aims to provide a broad overview of the field of biology.
• Biology is the scientific study of life.

Cell Biology

• The cell is the basic unit of life.
• Cells can be prokaryotic or eukaryotic.
• Prokaryotic cells lack a nucleus and other membrane-bound organelles, e.g., bacteria and archaea.
• Eukaryotic cells contain a nucleus and other membrane-bound organelles, e.g., animal, plant, fungi, and protist cells.
• Key cell structures include the plasma membrane, cytoplasm, and nucleus.
• The plasma membrane controls the movement of substances in and out of the cell.
• The cytoplasm is the gel-like substance within the cell where organelles are located.
• The nucleus contains the cell's genetic material (DNA).
• Organelles perform specific functions within the cell.
• Ribosomes are responsible for protein synthesis.
• The endoplasmic reticulum (ER) is involved in protein and lipid synthesis.
• The Golgi apparatus modifies and packages proteins.
• Mitochondria are the powerhouses of the cell, producing ATP through cellular respiration.
• Chloroplasts (in plant cells) are the sites of photosynthesis.
• Lysosomes contain enzymes for intracellular digestion.
• The cytoskeleton provides structural support and facilitates cell movement.
• Cell size and shape are related to their function.
• Cells communicate with each other through various signaling pathways.

Genetics

• Genetics is the study of heredity and variation.
• DNA (deoxyribonucleic acid) is the genetic material.
• DNA is a double helix composed of nucleotides.
• Nucleotides consist of a sugar, a phosphate group, and a nitrogenous base (A, T, C, or G).
• Genes are segments of DNA that encode proteins.
• The flow of genetic information is DNA → RNA → Protein.
• DNA replication is the process of copying DNA.
• Transcription is the process of synthesizing RNA from a DNA template.
• Translation is the process of synthesizing protein from an RNA template.
• Mutations are changes in the DNA sequence.
• Mutations can be spontaneous or induced by mutagens.
• Types of mutations include point mutations, insertions, deletions, and chromosomal rearrangements.
• The genome is the complete set of genetic material in an organism.
• Chromosomes are structures that carry genes.
• Humans have 46 chromosomes (23 pairs).
• Mitosis is cell division that results in two identical daughter cells.
• Meiosis is cell division that results in four haploid daughter cells (gametes).
• Mendelian genetics describes the inheritance of traits.
• Alleles are alternative forms of a gene.
• Genotype is the genetic makeup of an organism.
• Phenotype is the observable characteristics of an organism.
• Dominant alleles mask the expression of recessive alleles.
• Punnett squares are used to predict the genotypes and phenotypes of offspring.
• Sex-linked traits are traits that are inherited on the sex chromosomes.
• Genetic engineering involves manipulating genes for various purposes.
• Polymerase chain reaction (PCR) is a technique used to amplify DNA.
• Gel electrophoresis is a technique used to separate DNA fragments.
• DNA sequencing is a technique used to determine the nucleotide sequence of DNA.

Evolution

• Evolution is the change in the genetic makeup of a population over time.
• Natural selection is the mechanism of evolution.
• Natural selection favors individuals with traits that enhance survival and reproduction.
• Adaptation is the process by which organisms become better suited to their environment.
• Evidence for evolution includes fossils, comparative anatomy, embryology, and molecular biology.
• The fossil record shows the history of life on Earth.
• Homologous structures are structures in different species that have a common ancestry.
• Analogous structures are structures in different species that have similar functions but different ancestries.
• Vestigial structures are structures in organisms that have lost their original function.
• Embryology studies the development of embryos.
• Molecular biology studies the molecular basis of life.
• Speciation is the process by which new species arise.
• Allopatric speciation occurs when populations are geographically isolated.
• Sympatric speciation occurs when populations are not geographically isolated.
• Phylogeny is the evolutionary history of a group of organisms.
• Phylogenetic trees are used to represent evolutionary relationships.
• The three domains of life are Bacteria, Archaea, and Eukarya.

Ecology

• Ecology is the study of the interactions between organisms and their environment.
• The environment includes biotic (living) and abiotic (non-living) factors.
• Populations are groups of individuals of the same species living in the same area.
• Communities are assemblages of different populations living in the same area.
• Ecosystems are communities and their physical environment.
• The biosphere is the global ecosystem.
• Population ecology studies the factors that affect population size and growth.
• Population growth can be exponential or logistic.
• Carrying capacity is the maximum population size that an environment can support.
• Community ecology studies the interactions between different species.
• Types of interactions include competition, predation, mutualism, and parasitism.
• Competition occurs when two or more species require the same limited resources.
• Predation occurs when one species (the predator) feeds on another species (the prey).
• Mutualism is a relationship in which both species benefit.
• Parasitism is a relationship in which one species (the parasite) benefits and the other species (the host) is harmed.
• Ecosystem ecology studies the flow of energy and nutrients through ecosystems.
• Energy flows through ecosystems in one direction.
• Nutrients cycle through ecosystems.
• Food chains and food webs describe the feeding relationships in an ecosystem.
• Trophic levels are the positions of organisms in a food chain or food web.
• Primary producers (autotrophs) are organisms that produce their own food through photosynthesis or chemosynthesis.
• Consumers (heterotrophs) are organisms that obtain energy by feeding on other organisms.
• Decomposers are organisms that break down dead organic matter.
• Biodiversity is the variety of life in an ecosystem.
• Conservation biology aims to protect and preserve biodiversity.
• Human activities can have a significant impact on ecosystems.
• Pollution, habitat destruction, and climate change are major threats to biodiversity.

Explore cell biology in Biology 151. Understand the basics of cell structure. Learn the functions of prokaryotic and eukaryotic cells. Discover key components like the plasma membrane, cytoplasm, and nucleus.