Biology Exam 2

Chapter 3+4+5

Prokaryotes include

• Bacterial

• Archaea

• Is a single celled organism wiht no nucleus

Eukaryotes

• Contains organelles, has a nucleus, can be single celled or a multicellular organism

• Plants

• Animals

• Fungi

• Algae etc

Who built the first compound microscope

Robert Hooke

Who was the first to observe bacteria with a single lens microscope?

Anthony Van Leeuwenhoek

Cell theory

1. All organisms consist of one or more cells

2. The cell is the basic unit of life

3. All cells come from pre-existing cells

1800s Cell Theory

• All plants are made of cells

• All animals are made of cells

• All living things are composed of cells and cell products

Two main types of cells:

Prokaryote - “before nucleus”

Eucaryote - “true nucleus”

Plasma (cell) membrane

encloses cell

Cytoplasm

water based fluid with organelles

Ribosomes

where proteins are made

DNA

in cytoplasm (prokaryotes) or nucleus (eukaryotes)

What is in charge of the cell?

Nucleus

Nucleus

• contains DNA

• RNA copies of active genes are made here

• makes ribosomes

What moves things around in the cell?

Endomembrane System

• starts at the nucleus

• makes proteins and lipids

What does the endomembrane system contain?

• Endoplasmic Reticulum (ER)

• Golgi apparatus

• Vesicles + vacuoles + lysosomes

Endoplasmic Reticulum:

The store/Factory

• Rough and Smooth ER

Rough ER

• Has ribosomes - make chains of amino acids

• Chains enter the ER - folded up into 3D proteins

Smooth ER

• Makes lipids and steroids

  • phospholipids for membranes

• Detoxification

Golgi apparatus: The Post Office

• Recieves proteins + lipids from ER

• Some more protein + lipid finishing

• Packages proteins/lipids in vesicles for delivery

Vesicles: The Delivery Trucks

• Bud off ER, Golgi, or plasma membrane

• Transport between organelles

What do cells have in common

• cytoplasm

• cell membrane

• DNA

• has Ribosomes

Vacuoles

• Type of vesicle

• Varying functions, e.g. pumps out water in some protozoa

• Larger than vesicles

• Other uses in plants

Lysosomes: Garbage Truck

• Type of vesicle

• Handles all the waste

• Filled with digestive enzymes

What keeps things in their place?

Cytoplasm

Cytoplasm

• watery fluid (cytosol)

• organelles

  • small organs in cell

• Cytoskeleton fibers

  • reinforce cell shape, organize and move cell structures

What produces Energy?

Mitochondria

Mitochondria

• double membrane - separate compartments

• cellular respiration - ATP synthesis

• numerous in active cells

• have own DNA

  • circular like bacteria DNA

  • replicate independently

Plant cells have a

Large vacuole

How are plants different from animals?

• photosynthesis (producer)

• They dont have a skeleton

How do plants keep their shape?

Cell wall and Vacuole

• Cellulose forms the cell wall

• Fluid-filled central vacuole helps to support plant cells

How do chloroplasts create sugars?

Chloroplasts

Chloroplasts

• plants and algae

• double outer membrane

• have their own DNA-circular

• Photosynthesis

Photosynthesis

Chlorophyll pigments capture light energy from the sun and build sugars from CO2 and H2O

What protects the Cell?

Plasma membrane

________ is selectively permeable - regulates what’s allowed in and out

• keeps conditions inside the cell separate from outside

Plasma membrane

The cell Membrane

• fluid mosaic

• selectively permeable

Three types of transport across membranes:

1. Passive Transport

2. Active Transport

3. Endocytosis - Exocytosis

Passive Transport

requires no energy, molecules diffuse down the concentration gradient

• diffusion (and osmosis)

• facilitated diffusion

Active Transport

requires energy input (ATP), molecules move against their concentration gradient

Endocytosis - Exocytosis

move stuff with vesicles

Diffusion

• Spreading of molecules from areas of high concentration to areas of low concentration

• does not require energy input

Rate of diffusion is influenced by:

1. concentration gradient

2. size/mass of molecules

3. temperature

Facilitated Diffusion

• Diffusion accomplished with the help of proteins

How does water move?

• Osmosis - a special kind of diffusion

• Diffusion of water across a semipermeable membrane

Concentration gradient

Easy for passive transport

Tough with active transport

Endocytosis

e.g. “eating” of bacteria cells

Exocytosis

e.g. secretion of digestive enzymes by pancreas cells

isotonic solution

Equal solute inside and outside ——> water enters/leaves at equal rates ——> cell shape remains unchanged.

Hypertonic Solution

Higher solute outside ——> water leaves the cell ——> cell shrinks/shrivels.

Hypotonic

• Lower solute outside → water enters the cell → cell swells and may burst (lyse).

Types of passive transport

• simple diffusion

• osmosis

• facilitated diffusion

Why do organisms need energy?

• moving, eating, sleeping, thinking

How do organisms get energy

producers - photosynthesis

consumers - cellular respiration (food chain)

Autotrophs

make their own food

What is energy?

The ability to do work

Three main types of energy:

• light

• kinetic

• chemical

______ makes ATP through cellular respiration

the mitochondria or the “powerhouse”

the first law of thermodynamics

Energy can neither be created nor destroyed. It can be converted from one form to another

• light NRG to chemical NRG

• chemical NRG to kinetic NRG

Anabolism

building up

• Energy is used

Catabolism

breaking down

• energy is released

Metabolism

all the chemical reactons that take place inside of cells

Purpose of metabolism

• converting food to energy for cellular respiration

• building glucose to use for energy (photosynthesis)

• converting food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates

• eliminating wastes

Photosynthesis is which type of metabolism

anabolic (uses energy)

Respiration is which type of metabolism

catabolic (produces energy)

Activation energy

energy needed to get a reaction going

What helps reactions start?

Enzymes:

• speed up chemical reactions

• catalysts

• makes it easier for the reaction to get going (lower activation energy)

• most are PROTEINS

What do cells use for energy?

ATP - Adenosine Triphosphate

How is ATP formed?

1. Glycolosis

2. Citric Acid Cycle (Krebs cycle or TCA cycle)

3. Oxidative Phosphorylation

Glycolysis

• In the cytoplasm

• ONE 6-carbon glucose —→ TWO carbon pyruvate

• also produces 2 ATP

• anaerobic

What to know about glycolysis

• Start as glucose (energy is used)

• go from 2 ATP to 2 ADP

• Produce 2 pyruvate

• 2 NET ATP AND TWO NET NADH ******

What happens in the mitochondria?

CAC Citric acid cycle or Krebs

Citric acid cycle

• inside mitochondrial matrix

• does not require O2 (anaerobic)

• 2 pyruvate broken down

  • produces 2 ATP, 6 CO2 (exhaled), energy carriers NADH + FADH2

Citric Acid Cycle Equation

C6 H12bO6 + O2 ——> 6 CO2 + 6 H2O + ATP + Heat

Oxidative Phosphorylation

• On inner mitochondrial membrane

• - NADH + FADH2 molecules are used to pump H+ ions into the space between the inner and outer membrane

• electron transport chain

H+ gradient powers ____

ATP synthesis - about 34 ATP

Glycolysis and Respiration summary equation

Glucose + oxygen → → → carbon dioxide + water + energy
 C₆H₁₂O₆ + 6 O₂    6 CO₂ + 6 H₂O + ~38 ATP + heat

NADH produces ___ ATP and FADH2 produces ____ ATP?

3, 2

how many ATP for 1 molecule of glucose?

38

What if there is not enough O2?

• Products of glycolysis are fermented

  • to lactic acid (e.g. humans)

  • to alcohol (yeast)

How does it equal 38 ATP in 1 glucose?

2 ATP glycolysis

2 ATP Citric Acid Cycle

34 ATP oxidative phosphorylation

Do we only breakdown glucose for ATP?

No, we can convert proteins, carbohydrates, amd fats

Producers

•Use carbon from CO₂ and sunlight as energy to produce sugars  autotrophs

Consumers

•Get carbon from breaking down (digesting) organic molecules from other organism

  heterotrophs

Photosynthesis equation

Carbon dioxide + water + energy ———→ glucose + oxygen
     
        6 CO₂    + 6H₂O   + light     ———>    C₆H₁₂O₆ + 6 O₂

Where does Photosynthesis happen?

The middle layer called the mesophyll

The gas exchange of CO2 and O2 occurs in small openings called the stomata

Two parts of photosynthesis

1. Light-dependent reactions

2. Light-independent reactions

Light-dependent reactions

Take light energy and convert to chemical energy

  – in membrane of thylakoids

(Photophosphorylation)

Light-independent reactions

Use that chemical energy to make sugar molecules

  – in stroma (like cytoplasm)

What is light?

Electromagnetic radiation

• Visible light is part of the spectrum and different parts of the spectrum show different colours

In photosynthesis, light is captured by…

Pigments

Pigments

Capture light of certain wavelengths

• different pigments absorb different wavelengths

• chlorophyll is the most common

Why are plants green if chlorophyll, the most common pigment is using red and blue light?

It is absorbing the red/blue light and reflecting green

Where do light-dependent reactions take place and what do they do?

• In thylakoids

•Light energy hits pigments

•Splits H₂O with light → O₂ leaves into air

•H⁺ build up inside thylakoids

•H⁺ gradient is used to make ATP (similar to respiration)

purpose is to convert light energy into chemical energy

What affects photosynthesis?

Water availability

• during drought, close stomata to prevent water loss

  • also prevents movement of ocygen and carbon dioxide

Temperature

• Enzymes denatured when too warm

• Reaction slows when too cold

Benefits of Photosynthesis

• produces sugars that we eat

• releases oxygen that we breathe

• absorbs carbon dioxide that we exhale

Which of the following is NOT part of the cell theory?

All cells have a nucleus to contain their DNA

How many molecules of net ATP are produced if one molecule of glucose is completely metabolized?

38

Which of the following is true regarding why leaves are green?

Chlorophyll absorbs red and blue light

ATP is not very …

stable

Transferring energy from ATP into siugars allows plants to store that energy long term

EX. no sun, move to roots

• can break down when energy is needed later