Exam 1 Review

Chapter 1-5

list the biology core concepts

1. life evolves over time

2. structure & function are interrelated

3. life processes involve information flow

4. matter & energy are transformed

5. biology consists of complex systems

list the levels of biological organization from smallest to largest

1. atoms

2. molecules

3. cells

4. tissues

5. organs

6. organisms

7. populations

8. communities

9. ecosystem

10. biosphere

example of population

population of bears

example of communities

population of bears and foxes in the forest

example of ecosystem

the coral reef

example of unity on a macro scale

1. eyes

2. bones

3. organs

example of unity on a micro scale

1. cell structure

2. organelles

3. DNA

4. proteins

example of diversity on a macro scale

1. size

2. coloration

3. body shape & size

example of diversity on a micro scale

1. physiology

2. proteins

3. DNA sequence

charles darwin 2 ideas

1. descent with modification

2. natural selection

descent with modification

traits are passed down from generation to generation and sometimes undergo changes or modifications over time

natural selection

organisms with advantageous traits are able to produce more offspring that will pass on those traits

example of: life evolves over time

• natural selection

• genetic variation

• mutations

example of: structure & function are interrelated

structure of bird wings are adapted for flight (shape, lightweight bones, feathers)

example of: life processes involve information flow

neurons transmit information to other cells in the body

example of: matter and energy are transformed

cellular respiration: cells convert glucose (energy) and oxygen into CO₂ and H₂O (matter)

example of: biology consists of complex systems

a human’s nervous system, respiratory system, cardiovascular system, etc

different pieces of evidence indicating that life derives from common ancestry

1. fossil records

2. anatomical features from different species

3. molecular evidence (genetics)

4. biogeography

conditions that are necessary for natural selection to occur

• Variation: Differences in traits among individuals.

• Heredity: Traits can be passed from parents to offspring.

• Differential Reproduction: Not all individuals reproduce equally.

• Environmental Pressure: Challenges to survival and reproduction.

• Fitness: Traits that help survival and reproduction.

• Selection Pressure: Advantageous traits become more common.

• Time: Takes many generations for significant change.

• Non-Random Reproduction: Reproduction influenced by specific traits.

• Accumulation: Beneficial traits accumulate in the population.

• Selective Advantage: Traits greatly improve survival and reproduction.

explain how natural selection can lead to two different populations with features that are uniquely adapted to their particular environment

species will develop unique adaptations due to their environment will become more prevalent over time, making them better suited to survive

types of selection

1. natural

2. sexual

3. viral

4. artificial

sexual selection

reproductive mate provides pressure

artificial selection

humans provide pressure

essential elements

required for organisms to survive, grow, and reproduce

list the essential elements

1. oxygen

2. carbon

3. hydrogen

4. nitrogen

5. calcium

mass number (superscript)

protons + neutrons

atomic number (subscript)

number of protons (identity of atom)

valence electron

electrons occupying outermost shell

valence electron shells capacity

1st shell: 2 electrons

2nd shell: 8 electrons

isotopes

same element, different number of neutrons

carbon-14

used to date archaeological samples

• organisms incorporate carbon-14 in metabolism until death

• half life: 5,000 years

how is carbon-14 used to estimate how long ago an organism died

by measuring the remaining carbon-14 in a sample and comparing it to the initial amount of carbon-14 in the atmosphere

Interpret how the position of an atom on the periodic table can be used to determine the atoms properties and chemical bonding patterns.

1. Atomic Number: identifier

2. Period: indicates energy level or electron shell in which an atom’s valence electrons are located

3. Column (Group): similar chemical properties because they have same # of valence electrons

Describe how Van der Waals interactions can occur within nonpolar substances.

occur through temporary charge fluctuations

• induced dipole

Describe how the different properties of water help support life’s processes.

• excellent solvent

  • allows chemical reactions to occur

• high heat capacity

  • helps stabilize temperature within organisms

• high heat of vaporization

  • allows cooling to regular body temperature (sweating)

• co/adhesion

  • transport of water and nutrients in plants

• surface tension

  • allows insects to walk on water & capillary action

• density

  • ice forms on surface of water, insulating layers beneath

• ionization and pH regulation

  • critical for enzymatic reactions and stability of systems

how to predict whether a substance will readily dissolve in water based on its chemical properties.

1. polarity

2. ions

3. hydrogen bonding

4. hydrophilic

Acid

produces H+ ions (proton donor)

Base

produces OH- ions (proton acceptor)

Describe the relationship between pH and hydrogen ion concentration

The relationship between pH and H⁺ concentration is inverse. As pH increases, H⁺ concentration decreases, and as pH decreases, H⁺ concentration increases.

(pH = -log[H+]

describe how polymers form

dehydration synthesis: extends/joins polymers together by removing water molecule

describe how polymers break down

hydrolysis: breaks down polymers by adding a water molecule

carbohydrate function

• energy storage

• cell structure

carbohydrate composition

• Carbon, hydrogen, and nitrogen atoms

• (CH₂O)n

carbohydrate structure

• mono/di/polysaccharides

• linear or branched

protein function

• enzymes

• structural support

• transport

• immune defense

protein structure

• amino acids linked by peptide bonds

• consists of: amino group, carboxyl group, and R side chain

• has primary, secondary, tertiary, and quaternary structures

protein composition

C, H, O, N, S

lipid function

• energy storage

• insulation and cushioning

• cell membrane

lipid composition

C, H, O, and other elements

lipid structure

• hydrophobic

• phospholipids: glycerol + 2 fatty acid chains + phosphate group

• triglycerides: glycerol + 3 fatty acids

nucleic acid function

• info storage and transport

• DNA/RNA

nucleic acid composition

C, H, O, N, P

nucleic acid structure

• phosphate group (PO₄)

• sugar molecule

• nitrogenous base (ACTG)

saturated vs unsaturated fats

saturated

• no double bonds between carbon atoms

  • packs tightly = high melting point

• solid at room temp

unsaturated

• 1/more double bonds between carbon atoms = kind/bend

  • can’t pack closely = low melting point

• liquid at room temp

Describe how a phospholipid bilayer prevents the passage of certain materials and predict which materials are likely to cross a membrane based on their chemical properties.

• phospholipid: hydrophilic head and hydrophobic tails

  • nonpolar (hydrophobic) can pass through

  • polar (hydrophilic) can’t pass through

primary structure

amino acids joined by peptide bonds

secondary structure

alpha helices and beta sheets form in polypeptide chain, stabilized by hydrogen bonds

tertiary structure

3D arrangement of all amino acids in a polypeptide chain

• determined by interactions among side chains (R-groups)

quaternary structure

structure of proteins composed of two or more polypeptide chains

DNA vs RNA

• Genetic Information

  • DNA: carries gene info

  • RNA: carries out instructions based on gene info

• Sugar

  • DNA: deoxyribose sugar

  • RNA: ribose sugar

• Base

  • DNA: thymine

  • RNA: uracil

• Strands

  • DNA: 2

  • RNA: 1

• Function:

  • DNA: genetic info

  • RNA: gene expression, protein synthesis

plasma membrane

regulates passage of molecules in/out of cell

cytoplasm

gel-like substance within cell membrane where various cellular processes occur

genetic material

• Prokaryotes: DNA in nucleoid region

  • Eukaryotes: DNA in nucleus

ribosomes

responsible for protein synthesis

• found in cytoplasm or attached to ER

cytoskeleton

network of protein filaments that provides structural support and helps maintain cell shape

• made of: microfilaments, intermediate filaments, microtubules

cell wall

rigid outer layer that provides structural support

flagella and cilia

hair-like structures on outside of cell surface used for movement and/or sensing the environment

mitochondria

energy production

endoplasmic reticulum

protein synthesis and lipid metabolism

golgi apparatus

protein modification and packaging

lysosomes

digestion

Place different structures in order of increasing size.

• ribosomes

• plasma membrane

• cytoskeleton

• flagella/cilia

• eukaryotic cell organelles

• nucleus

light microscopy

• uses visible light

• benefit: less expensive, specimen can be alive

• disadvantage: many cellular structures not visible

electron microscopy

• uses electrons

• benefits: visual small structures

• disadvantages: expensive, can’t use live specimen

scanning electron microscopy

focus bean of electrons onto specimen to create 3D image

transmission electron microscopy

focuses beam of electrons through specimen

characteristics of eukaryote cells

• large size

• single/multicellular

• membrane-bound organelles

• nucleus inside DNA

• some have cell wall (plants)

characteristics of prokaryote cells

• small size

• unicellular

• no membrane-bound organelles

• no nucleus

• most have cell wall

similarities between eukaryotic and prokaryotic cells

• plasma membrane

• cytosol

• chromosomes

• ribosomes

organelles unique to eukaryotes

• nucleus

• golgi complex

• endoplasmic recticulum

• mitochondria

• lysosome

organelles unique to prokaryotes

• capsule

• DNA in nucleoid

certain features that enable these eu/prokaryotes to achieve reproductive success.

Eukaryotes

• membrane-bound organelles allows specialization of functions within cell

• mitosis and meiosis

• sexual reproduction: genetic diversity

Prokaryotes

• rapid reproduction

• efficient resource utilization

• genetic adaptability

endosymbiotic theory

some of the organelles in today’s eukaryotic cells were once prokaryotic microbes

endosymbiotic theory evidence

1. Membranes: some have double membranes

2. Antibiotics: susceptible to antibiotics

3. Division: reproduction occurs via a fission-like process

4. DNA: has own DNA (naked and circular)

5. Ribosomes: has own ribosomes

   (Many apply to mitochondria and chloroplasts)

characteristics unique to plant cells vs. eukaryotic

• rigid cell wall

• chloroplasts

• large central vacuuole

how does shape of a cell affect its surface-area to volume ratio

spherical shape

• low surface area to volume ratio

• limited transfer of materials across surface

• more storage

irregular shapes

• high surface area to volume ratio

• increases transfer of materials across surface

• less storage

which shape in nature is used more?

nature uses irregular shapes to maximize interactions w/ the environment

functions for a high surface area to volume ratio

• nutrient absorption

• gas exchange

• photosynthesis

• filtration

• heat dissipation

Ex: cells, microorganisms, roots

functions for a low surface area to volume ratio

• storage

• protection

• insulation

• slow metabolism - to conserve energy

Ex: elephant ears, succulents, deep sea fish

components that make up the endomembrane system

1. nuclear envelope

2. smooth & rough ER

3. golgi apparatus

4. vesicles

5. lysosomes

6. vacuoles (in plants)

nuclear envelope

double membrane that surrounds cell’s nucleus

• contains nuclear pores that allow exchange of materials between nucleus and cytoplasm

endoplasmic recticulum

rough ER:

• involved in protein synthesis, folding, and processing

• has ribosomes on surface

smooth ER:

• involved in lipid synthesis, detoxification, and calcium ion storage

• no ribosomes

golgi apparatus

flattened membrane sacs that receive, modify, and package proteins and lipids produced by the ER

• sorts and directs molecules to their appropriate destinations within or outside cell

vesicles

small membranous sacs that transport materials between the different components of the endomembrane system and to other cellular locations

• Ex: transport vesicles

lysosomes

membrane-bound organelles containing digestive enzymes

• breaks down cellular waste, debris, and foreign materials (through autophagy)

vacuoles

large membrane-bound sacs found in plant cells that store water, nutrients, and waste products; can also play a role in maintaining turgor pressure and supporting the cell’s structure

why does the endomembrane system represent a separate compartment within cells

1. membrane barriers

2. specialized functions

3. material processing and transport

4. isolation of reactions

why are certain proteins synthesized in different places within the cell

the synthesis of proteins in different places is a highly regulated and organized process that ensures proteins are produced, modified, and directed to the appropriate cellular locations to perform their specific functions

process of the endomembrane system

1. synthesis of molecules (can be free in cytoplasm or attached to ER)

2. enter the ER

3. newly synthesized proteins bud off from ER then fuse to gogli apparatus

4. inside golgi: proteins undergo additional post-translational modifications or sorts proteins/lipids into vesicles

5. vesicles containing sorted materials bud off and transported to final destination (can fuse with other organelles/cell membrane, releasing contents or into extracellular space)

key features of fluid-mosaic model

1. fluidity of individual lipid molecules

2. consists of lipids, proteins, and carbohydrates

3. lipid bilayer & its fluidity

4. proteins embedded within lipid bilayer

5. cholesterol stabilizes the membrane