Cell Structures and Functions

Lesson 3

Prokaryotic Cells

• first cell type of earth

• cell type of bacteria and archaea

Prokaryotic Cells

• no membrane bound nucleus

• nucleoid = region of DNA concentration

• Organelles not bound by membranes

Capsule

sticky outer layer that provides protection

Cell Wall

confers rigidity and shape of the cell

Plasma Membraine

permeability barrier, produces energy, aids in communication, and supports essential cell processes

Plasmid

genetic material (Circular DNA)

Nucleoid

• control center

• where the main DNA is stored

Cytoplasm

• the workshop of the bacterial cell where all life processes take place

Ribosomes

protein-making machines

Pilus/Pili

hair-like appendage functions in adhesion

Flagellum

facilitates movement

Eukaryotic Cells

• Nucleus bound by membrane

• include fungi, protist, plant, and animal cells

• possess many organelles

organelle

are the different structures inside a cell that each have different jobs and functions to complete within the cell

Cell membraine

• selectively permeable membrane (regulates the entry and exit of substances into the cell)

• double layer of phospholipids and proteins

Phospholipids

• hydrophilic head (water-loving)

• Hydrophobic tail (water-fearing)

Cytoplasm

the fluid that fills a cell; is found in both animal and plant cells and is made up of many dissolved molecules that can be used for other processes throughout the cell.

Endoplasmic Reticulum

• “E.R.“

• helps move substances within cells

• network of interconnected membranes

Rough Endoplasmic reticulum

• “R.E.R“

• ribosomes attached to the surface

• manufacture proteins

• folds and modifies proteins before sending them to the Golgi apparatus

Smooth endoplasmic reticulum

• “S.E.R.“

• No attached ribosomes

• makes lipids (fats, oils, steroids)

• helps detoxify harmful substances (especially in liver cells)

• stores calcium ions (important in muscle cells)

Golgi apparatus

• sorting, packaging, and shipping center of the cell

• Cis face — the receiving side (near ER)

• Trans face — shipping side (faces the cell membrane)

Mitochondria

• have their own DNA

• bound by double membrane

• break down glucose and oxygen into ATP (cellular respiration)

• energy factory of the cell

Lysosomes

• contain digestive enzymes

• aid in cell renewal

• breakdown old cell parts

• digest invaders

• cell death

• acidic pH

Apoptosis

Cell death

Peroxisome

• breaks down fatty acids

• detoxifies harmful substances (like alcohol in liver cells)

• uses hydrogen peroxide (H2O2) in reactions — contains catalase enzyme to break it into water + oxygen (so the cell doesn’t get poisoned)

• Neutral pH

Secretory granules

delivery trucks (carrying proteins, hormones, enzymes to send out of the cell)

Lipid droplets

• storage tanks (storing fats and oils for energy and building materials)

Ribosomes

• protein builders of the cell

• made of mRNA (ribosomal RNA) and proteins

• floating freely in the cytoplasm (make proteins used inside the cell)

• Or attached to the rough ER (make proteins for export or for membranes)

Centrioles

• helps the cell divide during mitosis and meiosis

• are only found in animal cells and are made up of multiple microtubules

cytoskeleton

• mechanical support, anchor organelles, and help move substances

• made of 3 types: Microfilaments, Microtubules, Intermediate Filaments

Microfilaments

• thinest fibers (About 7 nm thick)

• made of actin protein

• help the cell move, supports the cell’s shape, aid in cell division

Cytokenisis

Cell division; the cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.

Intermediate Filament

• medium thickness (about 10 nm)

• Made of different proteins (like keratin)

• provide mechanical strength, anchor organelles like the nucleus in place, found more in animal cells than plant cells

Microtubules

• thickest fibers (about 25 nm)

• made of tubulin protein

• form cilia and flagella (for movement)

• act as tracks for moving organelles and vesicles inside the cell

• help separate chromosomes during cell division (spindle fibers)

glycogen granules

• act as the cell’s energy reserve

• found in liver cells to regulate blood and sugar

• found in muscle cells to give quick energy during exercise

pigments

• colored substances found in cells that can absorb and reflect light ex: chlorophyll, carotenoids, hemoglobin, melanin

nucleus

the control center of both plant and animal cells that controls growth and reproduction

Nuclear Membrane

• double-layered membrane that surrounds the nucleus

• protects the DNA and controls what enters and leaves the nucleus

Nucleolus

• found inside the nucleus

• make ribosomes, which are needed for proteins synthesis

Nuclear pores

• regulate the transport of molecules between the nucleus and cytoplasm

Cell wall

• the outer layer of plant cells that helps keep everything inside the cell protected

Vacuole

• storage bubble that stores food and nutrients the cell needs to survive

• are found in both plant and animal cells but are larger in plant cells

Plastids

• carry out photosynthetic function in plants

Chloroplast

• converts light energy of the sun into sugars used by cells

• is the organelle where photosynthesis takes place and is only found in plant cells (uses sunlight, water, and carbon dioxide)

• green due to chlorophyll

Chlorophyll

green pigment found in plants

Chromoplast

• red, orange, or yellow (because of pigments like carotenoids)

• provides color to flowers, fruits, and some leaves

• attracts pollinators and animals for seed dispersal

Leucoplast

• colorless

• storage of different substances

• found mostly in roots, seeds, and tubers (like potatoes)

Amyloplast

leucoplast that store starch

Elaioplasts

leucoplast that store oils

Proteinoplasts

leucoplast that store proteins

Microvilli

cell membrane extensions that increase surface area to enhance nutrient absoption

Cilia

• short numerous, hair-like projections

• move substances across cell surfaces (e.g., mucus in respiratory tract)

• help in locomotion for some single-celled organisms (e.g. Paramecium)

Flagella

• long, few (often 1-3 per cell), whip-like tails

• moves in a smooth, wave-like tail motion

• locomotion (e.g. sperm cells, euglena)

Root Hairs

• increase the surface area of roots to absorb more water and minerals from the soil

Plant Cell

Cell that have cell walls and have larger vacuoles

Animal cell

• don’t have a cell wall - only a cell membrane

• have centrioles