Unit 1: Cells

DP1 Bio SL1 Unit 1 Review

Ribosomes

Ribosomes

Makes proteins

Rough Endoplasmic Reticulum (Rough ER)

Transports and modifies proteins that were made by ribosomes

Golgi Apparatus

Stores, modifies, and packages proteins for transport

Vacuoles

Stores materials like water, food, other nutrients and waste products(very large in plants)

Lysosomes

filled with enzymes for breakdown of large molecules or unwanted materials

Nucleus/Nuclear Membrane

Surrounds and contains DNA

Mitochondria

carries out cellular respiration

Chloroplasts

Contains chlorophyll and where photosynthesis occurs

Cell Wall

Rigid structure surrounding cells

Cell (Plasma) Membrane

controls the movement in and out of the cell

cytoplasm

space inside the cell that contains water, disolved materials, etc.

DNA

holds genetic information

How is the Miller Urey important in our understanding of the origin of cells?

It provided a model for how simple atmospheric molecules could've led to the creation of more complex, organic molecules

What evidence is there that all living things share this ancestor? (LUCA)

All living things are made of cells, they all have the same characteristics of life, and some jeans and enzymes are the same too

Characteristics that all living things share

Metabolism, response, excretion, growth, reproduction, homeostasis, nutrition

Cell theory

Cells are the smallest unit of structure and function in living things, all living organisms are made of one or more cells, all cells come from pre-existing cells

how are muscle fibers an “atypical” cell?

they contain more than one nucleus, unusually large, instead of the typical spherical shape muscle fibers are cylindrical structures

1mm=

1,000um

1,000um=

1mm

1 cm=

10mm

10mm=

1 cm

Endosymbiotic theory

One bacterium enters a larger bacterial cell or was engulfed by a larger cell. This larger cell now has a new ability due to the smaller one and the smaller one is protected by the larger one

Prokaryotic and Eukaryotic Similarities

- DNA
- Organelle: Ribosomes
- Makes proteins
- Cytoplasm
-Jelly-like fluid
- Plasma/Cell membrane

Prokaryotic Structures

- No nucleus
- Free-floating DNA
- No membrane-bound organelles

Eukaryotic Structures

- Large
- Complex
- DNA in nucleus
- Has membrane organelles
- Nucleus
- Mitochondria
- Endoplasmic Reticulum
- Golgi Apparatus

ribosomes

rough ER

golgi apparatus

vacuoles

lysosomes

nucleus

mitochondria

chloroplasts

Outer most layer in plant

cell wall

2nd layer in plant, outermost in animal

cell(plasma) membrane

Space inside

cytoplasm

DNA

Virus first hypothesis

Viruses evolved before cells. Viruses are simpler than cells so they came first.

regressive hypothesis

Viruses were originally small cells then they became parasites of larger cells and loss the ability to metabolize and reproduce

Escape genes/progressive hypothesis

Viruses evolved after cells with their own genes. DNA or RNA escaped from early cells, surrounded by a protein barrier

Lytic Cycle

DNA injected into the cell, The cell is used to make more viral DNA & protein, Cell bursts open releasing viruses and killing the cell

Lysogenic Cycle

The infected cell integrates the viral DNA into its own and divides by mitosis, making many more infected cells

What is the structure of a virus?

• Small

• genetic material (RNA or DNA)

• Capsid made of protein (that allows it to specifically infect a single type of host cell)

• Few or no enzymes (molecular tools)

Why are viruses not considered alive?

Viruses cannot reproduce without a living cell as their host

Viruses do not grow, do not have a cell membrane, or ribosomes (found in all cells)

Viruses do not have metabolic processes (using nutrition, energy, etc)

what evidence is there from mitochondria & chloroplast analysis for endosymbiotic theory?

Contains DNA like a prokaryotic cell

70S ribosomes (like a prokaryotic)

Has 2 membrane - the inner membrane more similar to a prokaryotic membrane and the outer membrane more similar to eukaryotic cells

Mitochondria divide / reproduce independently of the rest of the cell

The earliest cells were very simple - Cell membrane surrounding RNA. Why was the membrane important?

provided a protective barrier that separated the internal environment of the cell (where RNA and other molecules resided) from the external environment. This allowed for several key functions

How to calculate magnification when given actual size, magnification, or image size (no image)

Magnification = image size/ actual size

How to calculate magnification given an image and scale bar (finding actual size)

Determine how many times you can fit the scale bar across the image. Multiply by length of bar.

How to calculate magnification given image and scale bar (finding magnification)

Magnification = size of scale bar/ label of scale bar