IB Biology - Unit 4: Cells

Three domains of life

Bacteria, Archaea, Eukarya

Four kingdoms in Eukarya (Multicellular organisms)

Protists, Plants, Fungi, Animals

Prokaryotic cell

Cell that does not have a nucleus or other membrane-bound organelles. With an outer wall of peptidoglycan and don't have cell compartmentalization

Animal cell

Eukaryotic cell containing membrane-bound organelles without a cell wall or chloroplasts

Plant cell

Eukaryotic cell containing membrane-bound organelles. A cell wall made of cellulose and chloroplasts

Fungal cell

Eukaryotic cell with a chitin cell wall

Structures present in ALL cells

Cytoplasm

Three principles of cell theory

1: All living things are composed of cells. 2: The cell is the smallest unit of life. 3: Cells only arise from pre-existing cells

Eight processes of life

Nutrition. growth. excretion. reproduction. homeostasis. response. movement. metabolism

Anucleate

Cell lacking a nucleus (eg. mature red blood cells & sieve tube in pholem of plants)

Multinucleate

Cells with multiple nuclei (eg. skeletal muscle & aseptate fungal hyphae)

Light microscopes

Use light and glass lenses to magnify an image

Electron microscopes

Produce magnified images by focusing beams of electrons with higher resolutions than light microscopes

Resolution

Shortest distance between two separate points in a microscopic field of view

Techniques of electron microscopy

Freeze fracture. cryogenic. immunofluorescence. fluorescent dyes

Magnification formula

Magnification = Image size / Actual size

Actual size formula

Actual size = Image size /Magnification

Cellular organelle

A structure found within a cell (typically in a membrane) that performs a specific function (typically metabolic)

Cell compartmentalization

The division of a cell into regions or compartments with a single/double membrane between them to isolate (eg. mitochondria & nucleus & golgi apparatus)

Structures that AREN'T organelles

Cell wall & cytoplasm & cytoskeleton

Organelles in prokaryotic cells

70S ribosomes & plasma membrane

Compartmentalization between nucleus and cytoplasm

Found in Eukaryotic cells. For processing transcription and translation

Compartmentalization in the cytoplasm

Near lysosome for digestive enzymes to occur and to prevent danger. this provides efficiency and protects the cells to not digest or allow the pathogen to infect

Stem cells

Unspecialized & undifferentiated cells that become other cells and can divide and differentiate (also found in adult humans)

Stem cell niche

Microenvironment where stem cells live and receive their instructions to make more stem cells and differentiate (eg. muscle & skin & liver & bone marrow)

Unipotent

Divides endlessly and differentiates to one cell type (eg. liver stem cell)

Multipotent

Divides endlessly and differentiates to few related cell types (eg. adult bone marrow)

Pluripotent

Divides endlessly and differentiates to most cell types except placenta cells (eg. cells of later embryo)

Totipotent

Divides endlessly and differentiates to any cell type including placenta cells (eg. cells of early embryo)

Relationship between cell diameter and surface area/volume ratio

As cell diameter increases surface area/volume ratio decreases. Larger for more space

Centrioles

Bundle of microtubules that organizes chromosomes in cell division

Chloroplast

Double membrane organelle. Produces organic compounds via photosynthesis

Mitochondria

Double membrane organelle with highly folded inner membrane. Site of ATP production via aerobic cellular respiration

Nucleus

Double membrane organelle with pores enclosing linear chromosomes of DNA wrapped around histone proteins

Cytoskeleton

Filamentous scaffolding within cytoplasm that provides structure and aids in intracellular transport. Made of microtubules and microfilaments

Cytoplasm

Fluid in which various cellular organelles are suspended

Nucleoid region

Location in a prokaryotic cell where DNA is found

Flagella

Long & whip-like structures that help the cell move

Ribosome

Organelle made of RNA and protein that synthesizes polypeptides

Plasma membrane

Phospholipid bilayer with embedded proteins that controls what enters and exits the cell

Cell wall

Rigid outer layer that protects cell and maintains shape

Vacuole

Single membrane compartment used for storage (and in plants for water balance)

Rough endoplasmic reticulum

Single membrane organelle extending from the nucleus. Covered in ribosomes & transports newly synthesized proteins

Golgi apparatus

Single membrane organelle made of vesicles and folded membranes near the plasma membrane. Modifies proteins and packages them into vesicles for secretion

Smooth endoplasmic reticulum

Single membrane organelle that synthesizes and transports lipids

Cilia

Small & hairlike structures projecting from the cell membrane that aid in movement of the cell itself or adjacent fluids

Vesicle

Small & temporary & single membrane compartment used to transport materials within the cell

Lysosome

Small vacuole/vesicle filled with enzymes that hydrolyze macromolecules

Nucleoid region is found in…

Prokaryotic cells only

Cytoplasm is found in…

Prokaryotic and eukaryotic cells

Cell wall is found in…

Prokaryotic and eukaryotic cells

Flagella is found in…

Prokaryotic and eukaryotic cells

Plasma membrane is found in…

Prokaryotic and eukaryotic cells

Ribosome is found in…

Prokaryotic and eukaryotic cells

Vacuole is found in…

Eukaryotic cells only

Lysosome is found in…

Eukaryotic cells only

Centrioles is found in…

Eukaryotic cells only

Cilia is found in…

Eukaryotic cells only

Vesicle is found in…

Eukaryotic cells only

Nucleus is found in…

Eukaryotic cells only

Mitochondria is found in…

Eukaryotic cells only

Golgi apparatus is found in…

Eukaryotic cells only

Smooth endoplasmic reticulum is found in…

Eukaryotic cells only

Rough endoplasmic reticulum is found in…

Eukaryotic cells only

Chloroplast is found in…

Eukaryotic cells only

Cytoskeleton is found in…

Eukaryotic cells only