Prokaryotic vs. Eukaryotic Cells

• Cells are considered the smallest unit of living things
• Simple cells are prokaryotic
• Complex cells containing organelles with specific functions are eukaryotic

Prokaryotic vs Eukaryotic

• Prokaryotic and Eukaryotic cells both have a cell membrane and cytoplasm
• Eukaryotic cells have larger ribosomes, a nucleus, and organelles, while prokaryotic cells do not

Cell Parts and Organelles

• Cell membrane surrounds the cell and controls what enters and leaves
• Cell membrane recognizes other cells and maintains homeostasis
• Cytoplasm suspends organelles in eukaryotic cells and is enclosed within the cell membrane
• Nucleus controls cell activities and contains chromosomes made of DNA
• Mitochondria breaks down food to release energy
• Endoplasmic Reticulum can move and change proteins (rough ER) and produce lipids (smooth ER)
• Ribosomes makes proteins
• Golgi body/complex changes and packages cell products
• Lysosomes break down waste materials in the cell using acid and enzymes
• Vacuoles hold materials like water, and are large in plant cells

Organelles Found Only in Plant Cells

• Cell wall surrounds the cell membrane and supports and protects the cell
• Chloroplast contains chlorophyll (green pigment) for photosynthesis

Cellular Processes

• Homeostasis stabilizes conditions within a cell for normal internal equilibrium
• Energy conversion happens during photosynthesis, where plants use energy from the sun to make glucose
• During aerobic cellular respiration, mitochondria release energy from molecules like glucose
• Molecule transportation moves molecules in and out of cells across the cell membrane; active transport requires energy, but passive transport, like diffusion, does not
• Synthesis of new molecules allows cells to create new molecules from simpler molecules

Viruses

• Viruses are tiny, non-living structures that depend on a host cell and cannot be treated with antibiotics, they cause diseases
• Virus structure: head has nucleic acids (DNA or RNA) surrounded by a protein coat (capsid)
• Virus Reproduction - attaches to host cell, releases its nucleic acids, and the host cell makes viruses and dies

Cells

• DNA holds the genetic information that controls what a cell does and what molecules it can make
• Cells have nucleic acids, a cell membrane, ribosomes, cytoplasm, and organelles
• Cells divide into two similar cells after growth, and doesn't require a host cell

Cell Cycle

• Sequence of phases of cell growth and division
• Timing and rate of cell cycle are critical to an organism's normal growth and development
• Cell division frequency varies by cell type
• Interphase is for intense growth and enzyme production
• S phase is for DNA synthesis/replication
• G₂ phase is for growth and preparation for cell division
• Mitosis consists of prophase, metaphase, anaphase, and telophase
• Cytokinesis is when cytoplasm and organelles are divided
• Mitosis: the phase during the cell cycle in which the nucleus divides, resulting in identical daughter cells

DNA Molecule

• Contains genetic information
• Consists of two strands of complementary nitrogen base pairs
• Double helix structure
• DNA replication transforms one DNA molecule into two identical copies with enzymes
• Each DNA strand serves as a template for a new, complementary strand
• Each new DNA molecule contains half of the original molecule

Changes in Cells

• Disruption of the cell cycle causes a loss of control, leading to diseases like cancer such as uncontrollable cell division and cancerous tumors
• Cell differentiation is the process by which genetically identical cells become more specialized and different
• DNA, RNA, and environmental factors influence which genes are transcribed and expressed
• Blood cells and muscle cells are differentiated and perform specific functions in an organism

Biomolecules

• Carbohydrates contain carbon, oxygen, and hydrogen atoms in a 2:1 ratio
• Carbohydrates provides cell energy and structural molecules
• Lipids contain carbon, oxygen, hydrogen, and possibly other atoms
• Lipids are used for energy, as a cell membrane component, for protective coating, and as a chemical messenger
• Proteins contain carbon, nitrogen, oxygen, hydrogen, and possibly sulfur atoms
• Proteins are structural molecules, enzymes, hormones, and transport molecules
• Nucleic acids contain a carbohydrate group, phosphate group, and nitrogen base
• Nucleic acids are carriers of genetic information and instructions for protein synthesis

Organic Molecules

• Organic molecules are found in living systems and contain carbon atoms in rings or long chains
• Small organic molecules can link together to form larger, more complex molecules (polymers)

Specialized Plant Cells and Functions

• Leaf cells contain chloroplasts for photosynthesis and guard cells control size of stomates (pores) allowing gas transfer
• Stem cells include xylem cells that move water/minerals and pholem cells that move nutrients like glucose throughout the plant, also providing support for leaves, branches, and flowers
• Root epidermis cells on root hairs increase surface area to allow for the absorption of water and mineral nutrients