Cell Structures and Functions

Cell Wall ( rigid structure which surrounds the cell membrane) supports and protects-Plant Cell only Centriole-Reproduction in animal cell Chloroplast-Plant Cell-Energy producers)-trap sun’s energy to make glucose Parts of the Cell

Structural Organization Eukaryotic and Prokaryotic Cells Prokaryotic-cells without membrane-bound structures-unicellular Eukaryotic Cells- membrane bound organelles-multicellular

Eukaryotes vs. Prokaryotes Eukaryotes (animals, plants, fungi, protists) Prokaryotes (bacteria) differ greatly in structure.

Prokaryotic Cell Bacteria

Summary of differences! PROKARYOTIC CELLS EUKARYOTIC CELLS small cells (< 5 mm) larger cells (> 10 mm) always unicellular often multicellular no nucleus or any membrane-bound organelles always have nucleus and other membrane-bound organelles DNA is circular, without proteins DNA is linear and associated with proteins to form chromatin ribosomes are small (70S) ribosomes are large (80S) no cytoskeleton always has a cytoskeleton cell division is by binary fission cell division is by mitosis or meiosis reproduction is always asexual reproduction is asexual or sexual Alike both have cell membranes ,cytoplasm, and DNA as their genetic material

Plant Cells vs. Animal Cells

Plant Cells vs. Animal Cells Animal cells are very similar to plant cells except for the following major differences: Animal cells do not contain chloroplasts Animal cells are not surrounded by cell walls The vacuoles in plants are much larger than those of animals Vacuoles-Storage Tank of Cells-Plants generally contain one large vacuole-animal cells have several smaller ones. Major function of vacuoles in plants is to provide internal pressure against the cell wall to keep the plant firm. The water-filled vacuoles swell and make the plant plump. This plumpness keeps the plants from being limp and droopy.

Plant Cell

Animal Cell

Microscope Pictures of a Plant Cell and an Animal Cell Elodea Human Cheek Cells

Cell Parts and Their Functions: Specialized cell parts called organelles “little organs”

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Nucleus Cell Membrane Go to Section:

Cytoplasm Structure: gelatin-like fluid that lies between the cell membrane and the nuclear membrane Function: contains salts, minerals and organic molecules holds organelles eighty percent water and usually clear in color

Cytoplasm

Cytoskeleton Structure: a network of thin, fibrous elements made up of microtubules (hollow tubes) and microfilaments (threads made out of actin) Function: acts as a support system for organelles -maintains cell shape Not found in prokaryotic cells

Nucleus Structure: the nucleus is a sphere that contains another sphere called a nucleolus Nickname: “The Control Center” Function: storage center of cell’s DNA -manages cell functions Parts: Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes – responsible for genetic material and cell instructions

Nucleus

Nuclear Membrane / Envelope Nickname: Gate Keeper Function: Selective - chooses what goes in and out of the nucleus

Nuclear Membrane / Envelope

Inside the Nucleus Chromatin Function: Material in cells that contains DNA and carries genetic information and direct functions of a cell. Thin strands inside the nucleus. Forms chromosomes

When the cell get ready to divide it makes Chromosomes Function: Carries genetic information that control inherited characteristics such as eye color and blood type. DNA is always in the form of chromosomes.

Chromosomes

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Go to Section:

Ribosomes Nickname: “Protein factories” Function: Produce proteins Proteins are passed to the interior of the endoplasmic reticulum. From there they will be transported to the Golgi bodies. Found in all cells, prokaryotic and eukaryotic

Ribosomes

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Go to Section:

Endoplasmic Reticulum (ER) Nickname: “Roadway” Function: carries proteins and other materials from one part of the cell to another.

Rough Endoplasmic Reticulum (rER) Rough appearance because it has ribosomes Function: helps make proteins, that's why it has ribosomes

Smooth Endoplasmic Reticulum (sER) No ribosomes Function: makes fats or lipids

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Nucleolus Nucleus Cell Membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Complex Go to Section:

Golgi Complex Nickname: “The Shippers” Function: receives, packages, and distributes proteins and other materials to different locations inside/outside of the cell Appearance: stack of pancakes

Golgi Complex

Lysosomes Structure: circular, but bigger than ribosomes) Nickname: “Clean-up Crews” Function: to break down large food particles into particles the rest of the cell can use, and to destroy old cells. Also, breaks down old cell parts and release substances to reuse.

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies

Mitochondria Nickname: “The Powerhouse” Function: Produces most of the energy the cell needs to carry out its functions. Muscle cells have large numbers of mitochondria. Breaks down food to make energy -ATP (cellular respiration) ATP: is the major fuel for all cell activities that require energy

Animal Cell Cytoplasm Nucleolus Ribosomes Nucleus Cell Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies

Cell Membrane Nickname: “Gatekeeper” Function: forms outside boundary of animal cell and allows materials to move in and out of the cell Selectively permeable – allows some substances to move through and some cannot maintaining homeostasis.

Cell Membrane

Now let’s talk about structures only found in PLANT Cells!!

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Cell Membrane Section 7-2 Vacuole Cell Membrane Go to Section:

Vacuoles Nickname: Storage Tank Function: stores water, food, waste products, and other materials. Large Central vacuole in plants Not all animals have vacuoles. If they do they are small and more than one.

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Go to Section:

Chloroplasts Green in color because of chlorophyll, a green pigment. Structure: stacked sacs that contain chlorophyll surrounded by a double membrane Function: photosynthesis (conversion of light energy to chemical energy stored in the bonds of glucose). Green in color because of chlorophyll, a green pigment.

Chloroplasts

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Cell Wall Go to Section:

Cell Wall Structure: rigid wall made up of cellulose, proteins, and carbohydrate Either cellulose or chitin Function: rigid layer of non-living material that surrounds the cells of plants and some other organisms. Provides support and protection to the cell membrane Found outside the cell membrane in plant cells

Cell Wall

Plant Cell Cytoplasm Vacuole Smooth ER Ribosomes Chloroplasts Cell Membrane Cell Wall Nucleolus Golgi Bodies Nucleus Mitochondria Rough ER

Create a Venn Diagram of the Animal and Plant Cell Structures

Comparing Plant and Animal Cells No cell wall DNA has cell wall No chloroplasts Ribosomes chlorophyll in chloroplasts Small or no Cytoplasm large central vacuole vacuole Cell Membrane usually boxy or square Can change shape Cytoskeleton Mitochondria Golgi Bodies Endoplasmic Reticulum\ Smooth Rough Nucleus Nucleolus Nuclear Membrane

Cell Theory All living things are made of cells. 2. Cells are the basic structure and function in living organisms. 3. All cells come from other cells.

Cells vary in size large cell -- yolk of an Ostrich egg; salmon eggs most cells are microscopic in size

Surface to Volume Ratio Cells take in nutrients and get rid of wastes through the cell membrane Bigger Cell = more food and more waste (more materials pass through its outer surface) Volume increases, surface area increases too, but the volume grows at a much faster pace, If it gets too big, the surface area will not be able to take in nutrients or pump out waste.

Genetic Science Learning Center