Cell Structure and Function

Cell Structure and Function

• Cells are the fundamental units of life, possessing a complex internal structure and specialized organelles.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (plants, animals, fungi, and protists) have a nucleus and membrane-bound organelles.
• The cell membrane regulates the passage of substances in and out of the cell.
• The cytoplasm is the gel-like substance within the cell that surrounds the organelles.
• The nucleus contains the cell's genetic material (DNA).
• Mitochondria are the sites of cellular respiration, generating energy.
• Ribosomes synthesize proteins.
• Endoplasmic reticulum (rough and smooth) plays a role in protein synthesis and lipid metabolism.
• Golgi apparatus modifies, sorts, and packages proteins.
• Lysosomes contain digestive enzymes for waste breakdown.
• Vacuoles store water and nutrients in plant cells.
• Chloroplasts perform photosynthesis in plant cells.

Biological Molecules

• Carbohydrates are composed of carbon, hydrogen, and oxygen, providing energy. Examples include sugars and starches.
• Lipids are diverse molecules that include fats, oils, and steroids, important for energy storage and membrane structure.
• Proteins are polymers of amino acids playing numerous roles in structure, function, and regulation.
• Nucleic acids, DNA and RNA, store and transmit genetic information.

Cellular Respiration

• Cellular respiration is the process by which cells break down glucose to release energy in the form of ATP.
• Glycolysis is the initial step, breaking down glucose into pyruvate.
• The Krebs cycle occurs in the mitochondrial matrix, releasing carbon dioxide and generating electron carriers.
• The electron transport chain uses electron carriers to produce ATP.

Photosynthesis

• Photosynthesis is the process by which plants convert light energy into chemical energy in the form of glucose.
• It occurs in chloroplasts, specifically in the thylakoid membranes.
• Light-dependent reactions capture light energy and produce ATP and NADPH.
• Light-independent reactions (Calvin cycle) use ATP and NADPH to fix carbon dioxide into glucose.

Genetics

• Heredity is the transmission of traits from parents to offspring.
• Genes are segments of DNA that code for specific traits.
• Chromosomes are structures that carry genes.
• DNA replication ensures genetic material is copied accurately.
• Transcription creates RNA from DNA.
• Translation synthesizes proteins using the information in RNA.
• Mutations are changes in DNA sequence and can lead to variations.

Ecology

• Ecology is the study of the interactions between organisms and their environment.
• Ecosystems encompass all living and non-living components in a specific area.
• Populations are groups of individuals of the same species in an area.
• Communities are multiple populations interacting in an area.
• Biodiversity refers to the variety of life on Earth.
• Food chains and food webs depict energy flow between organisms.
• Biomes are large-scale regions with characteristic climate and life forms.
• Cycles like the water cycle, carbon cycle, and nitrogen cycle are essential for ecosystem functionality.

Evolution

• Evolution is the change in heritable characteristics of biological populations over successive generations.
• Natural selection is a key mechanism of evolution, favoring traits that enhance survival and reproduction.
• Adaptations are traits that enhance survival and reproduction in a specific environment.
• Speciation is the process by which new species arise.
• Common ancestry connects all life forms through evolutionary relationships.

Reproduction

• Asexual reproduction produces offspring genetically identical to the parent.
• Sexual reproduction involves the fusion of gametes (sperm and egg) creating a genetically unique offspring.
• Types of asexual reproduction include budding, binary fission, and fragmentation.
• Meiosis is the process that produces gametes.

Classification

• Organisms are classified into hierarchical categories (e.g., domain, kingdom, phylum, class, order, family, genus, species).
• Classification systems reflect evolutionary relationships.
• Binomial nomenclature is the two-part naming system for species using genus and species names.

Human Biology

• Human biology studies the structure and function of the human body and how it works.
• Systems like the circulatory, respiratory, nervous, digestive, and endocrine systems work together.
• The integumentary system protects the body from harm.