Life sciences unit test

Levels of organization: What’s the levels from smallest to largest in biology?

Organelle - cell - tissue - organ - organ system - organism - population - community - ecosystem - biosphere

Why do the levels of organization matter?

Studying multiple levels shows how changes at one level affect others. (E.g. cell failure - organ failure - organism illness)

Definition of species

Organisms that can interbreed and produce fertile offspring

Definition of population

Same species in one area

Definition of community

All living species in an area

Definition of ecosystem

Living (biotic) + non-living (abiotic) factors interacting

Definition of biosphere

All ecosystems on earth

Definition of abiotic

Non-living (sunlight, water temp, pH)

Definition of Biotic

Living (fish, algae, bacteria)

7 key themes of biology: define continuity

Life continues through reproduction and DNA

7 key themes of biology: define Changes through time

Evolution, genetic drift

7 key themes of biology: define Adaptions

Traits that help survival (e.g. bears fur changing to white to blend in more with certain environments)

7 key themes of biology: define Homeostasis

Internal stability (body temp, pH)

7 key themes of biology: define Unity

Shared DNA and cellular structure among all life

7 key themes of biology: define Diversity

Variety of species and traits

7 key themes of biology: define Interactions

Organisms affect and depend on each other and environment

1st component of cell (out of 4): Cell membrane

Controls entry/exit

2nd component of cell (out of 4): Cytoplasm

Fluid that holds organelles

3rd component of cell (out of 4): ribosomes

Makes proteins

4th component of cell (out of 4): DNA

genetic material

Why are the 4 components (cell membrane, cytoplasm, ribosomes, DNA) in all cells important?

All life needs structure, genetic info, and protein synthesis

What are the characteristics in prokaryotes?

-No nucleus

-No membrane-bound organelles

-Very small and simplistic cell

-More adaptable compared to Eukaryotes because of simplicity (can survive harsh conditions)

Example: bacteria

What are the characteristics in Eukaryotes?

-Has a nucleus

-Has many membrane-bound organelles (mitochondria, ER, etc.)

-The cell itself is very large and complex

Example: plants, animals, fungi

Definition of Endosymbiotic theory

Eukaryotic cells evolved when prokaryotes engulfed smaller prokaryotes, then became organelles (mitochondria and chloroplasts)

Evidence of the endosymbiotic theory:

1) Mitochondria and chloroplasts have their own DNA (circular)

2) Have double membranes

3) Reproduce independently (binary fission)

4) Have 70S ribosomes (like bacteria)

5) Similar size and structure to bacteria

Nucleus function?

Contains DNA, controls cell

Plasma membrane function?

Selective barrier; made of phospholipid bilayer + cholesterol + proteins

Cytoskeleton definition?

Gives shape, movement, structure

ER (smooth) definition?

Makes lipids, detoxifies

ER (rough) definition?

Studded with ribosomes; makes proteins

Ribosomes definition?

Protein synthesis

Lysosomes definition?

Breaks down waste and old organelles

Golgi body definition?

Packages and ships proteins

Vacuoles definition?

Stores materials (water, food)

Cell wall definition?

Structure/support (plants)

Cilia/Flagella definition?

Movement

What happens if lysosomes stop working?

Cell builds up waste and dies

Endocytosis definition?

Cell takes in material (engulfing)

Exocytosis definition?

Cell releases material (like insulin)

Example: Pancreatic cells release insulin using exocytosis

Transport: passive transport, active transport, and concentration gradient definition?

-Passive transport: No energy; moves with concentration gradient (high to low). Examples: diffusion, osmosis, facilitated diffusion.

-Active transport: Requires ATP; moves against gradient (low to high)

-Concentration gradient: Difference in concentration between inside/outside of cell

Importance of transport: maintains balance (if disrupted, cells can burst or shrivel)

Transport: Membrane permeability

-pass freely: small nonpolar molecules (O2, CO2)

-need transport: large or charged molecules (glucose, ions)

Example: freshwater fish to saltwater; water moves out of fish cells (osmosis), cells shrink, leads to dehydration

Metabolism: Autotrophs definition

Make own food (plants)

Without autotrophs there would be no producers, the food chain would collapse

Metabolism: Heterotrophs definition

Consume others (animals)

Photosynthesis location

Chloroplast

Photosynthesis equation

6CO2 + 6H2O + sunlight —> C6H12O6 + 6O2

Photosynthesis purpose

Make glucose for energy storage

Photosynthesis inputs and outputs

Inputs: CO2, H2O, light

Outputs: Glucose, O2

Cellular respiration location

Mitochondria

Cellular respiration Purpose

Releases energy from glucose

Cellular respiration equation

C6H12O6 + 6O2 —> 6CO2 + 6H2O + ATP

Types of Cellular respiration: Aerobic

uses oxygen (36 ATP)

Types of Cellular respiration: Anaerobic

No oxygen, uses less ATP (2 ATP)

Types of Cellular respiration: Lactic acid fermentation

In animals —> lactic acid + ATP

Types of Cellular respiration: Alcoholic fermentation

In yeast —> ethanol + CO2 + ATP

ATP definition

“Energy currency” - powers all cell activities and stores energy in phosphate bonds (ADP + P —> ATP)

Why lactic acid forms

When oxygen is low, cells switch to anaerobic respiration - produces lactic acid (causes muscle soreness)