bio

Test Topics (with textbook sections and other assignments)

8.1 – Life is Cellular (+ Cell Theory CER)

  • Describe the statements of Cell Theory, and understand which scientists made contributions. 

Cell Theory 

All living things are made of cells.

Cells are the basic units of structure and function in living organisms.

All cells come from pre-existing cells.


Matthias Schleiden (1838) – Stated that all plants are made of cells.

Theodor Schwann (1839) – Expanded the idea, stating that all animals are made of cells.

Rudolf Virchow (1855) – Concluded that all cells arise from pre-existing cells, completing the cell theory.



8.2 – Cell Structure (+ Cell Whiteboard and Eukaryotic Cell Project)

  • Compare and contrast prokaryotic and eukaryotic cells

Prokaryotic -     For simpler life forms 

-Unicellular

-Have a cell wall

-no nucleus (DNA is located in the nucleoid region)

-Smaller

-Simple 

-Mitochondria or organelles

-Flagella 

-Bacteria and Archaea

- found in single celled organisms like bacteria 


Same 

-Ribosomes 

-Cytoplasm 

-Cell membrane 

-DNA

-Cellular respiration 


Eukaryotic-   For complex multicellular organisms 

-Nucleus 

-larger 

-More complex (membrane bound organelles)

-Mitochondria, endoplasmic reticulum, golgi apparatus 

-Linear DNA 

-Mitosis and meiosis 

-Animals plants fungi and protists

-Cell wall for plant cells not animal 

-More complex structures 


  • Compare and contrast animal and plant cells in terms of structures present

Animal

-No cell wall 

-No chloroplasts (relies on mitochondria for energy)

-Round

-Lysosomes 

-mitosis and meiosis

-No plastids 

-Cillia or flagella 

-No glyoxysomes 

-Small vacuoles

Same

-Nucleus 

-Cell membrane 

-Organelles

-Cytoskeleton 

-Vacuoles 


Plant 

-Cell wall 

-Chloroplasts 

-Rectangular 

-No lysosomes

- No Centrioles 

-Plastids 

-Glyoxysomes 

-Large central vacuole

  • State the essential components of eukaryotic cell

Mitochondria - generate most of the chemical energy needed to power the cell's biochemical reactions.

Cell membrane - separates and protects the interior of a cell from the outside environment

Nucleus - contains all of the cell's chromosomes, which encode the genetic material. 

Cytoplasm - the gelatinous liquid that fills the inside of a cell

Nucleolus -  function is to produce and assemble the cell's ribosomes

Ribosome - macromolecular machines, found within all cells, that perform biological protein synthesis.

Vacuole/Vesicle - membrane-bound sacs that function in storage and transport.

Golgi Body - helps process and package proteins and lipid molecules

Cytoskeleton - a network of protein fibers that form the structural network of the cell

Lysosome - a membrane-bound cell organelle that contains digestive enzymes 

Endoplasmic Reticulum - a network of membranous tubes within the cytoplasm (transportation system) 


  • Explain the endosymbiotic theory regarding chloroplasts and mitochondria

The endosymbiotic theory suggests that chloroplasts and mitochondria originated from ancient bacteria engulfed by a primitive eukaryotic cell. Instead of being digested, these bacteria formed a symbiotic relationship with the host.

Mitochondria evolved from aerobic bacteria, helping the host produce energy (ATP).

Chloroplasts evolved from photosynthetic bacteria, allowing the host to perform photosynthesis.

Over time, these bacteria became permanent organelles within eukaryotic cells.



8.3 – Cell Transport (+ POGIL)

  • Describe the makeup of the cell membrane, including the fluid mosaic model

The cell membrane is a thin, flexible layer that surrounds the cell and controls what enters and exits. It is made up of:

Phospholipid Bilayer: Two layers of phospholipids with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward.

Proteins: Embedded in the membrane, they help transport materials, act as receptors, and provide support.

Cholesterol: Scattered within the bilayer, cholesterol molecules add flexibility and stability.

Carbohydrates: Often attached to proteins or lipids on the outer surface, they help in cell recognition and communication.


  • Differentiate between passive transport and active transport, including the types of molecules or conditions that allow passive transport

Active transport  is when water molecules leave against what is needs to do (activists) 

Passive transport is when water molecules go towards the concentration (get walked over/passive)

  • Explain the process of osmosis, giving examples of hypotonic, hypertonic, and isotonic solutions

Osmosis is the movement of water across a cell membrane from an area of low solute concentration to high solute concentration, aiming to balance water levels on both sides.

Solution Types:

  1. Hypotonic Solution: Lower solute concentration outside the cell than inside. Water enters the cell, causing it to swell or even burst.

    • Example: Freshwater around a saltwater fish.

  2. Hypertonic Solution: Higher solute concentration outside the cell than inside. Water leaves the cell, causing it to shrink.

    • Example: Saltwater around a freshwater plant.

  3. Isotonic Solution: Equal solute concentration inside and outside. Water moves equally in both directions, so the cell stays the same size.

    • Example: Saline solution with the same salt concentration as cells.

Osmosis keeps cells balanced by adjusting water levels based on the surrounding solution type.


  • Explain the impact on plant and animal cells when placed in hypotonic or hypertonic solutions

When plant and animal cells are placed in hypotonic or hypertonic solutions, water moves in or out of the cell by osmosis, causing different effects due to each cell's structure.

In a Hypotonic Solution: More water coming into

-Animal Cells: Water enters the cell, which can cause it to swell and possibly burst (lysis) because animal cells lack a rigid cell wall.

-Plant Cells: Water also enters, but the rigid cell wall prevents bursting. The cell becomes turgid (firm), which is generally beneficial for plant structure and growth.

In a Hypertonic Solution:

-Animal Cells: Water leaves the cell, causing it to shrink (crenation), which can impair cell function.

-Plant Cells: Water exits the cell, causing the cell membrane to pull away from the cell wall (plasmolysis), leading to wilting and potentially damaging the plant.

In short, hypotonic solutions make cells swell, while hypertonic solutions cause them to shrink.




Exocytosis and endocytosis are processes for transporting materials across the cell membrane:

  • Exocytosis: Moves materials out of the cell. Vesicles fuse with the cell membrane, releasing substances (like proteins or waste) outside the cell. Common in secretion and communication.

  • Endocytosis: Brings materials into the cell. The cell membrane engulfs external substances, forming vesicles to transport them inside. Used in nutrient intake and immune responses.

Key Difference: Exocytosis exports materials, while endocytosis imports them. Both processes use vesicles and require energy (active transport).