Biology Final

Characteristics of living things

1. Made of cells

2. Based on universal genetic code

   • Store complex information in DNA

   • Information is copied and passed from parent to offspring

3. Grow and develop

   • Every organism has a pattern of growth and development

4. Respond to their environment

5. Reproduce

   • Sexual reproduction

   • Asexual reproduction

6. Maintain a stable environment

   • Homeostasis

7. Obtain and use energy

   • Needed for growth, development, and reproduction

   • Metabolism

8. Evolve (as a group)

   • Groups of organisms change over generations

Sexual reproduction

Cells from two parents unite to form the first cell of a new organism

Asexual reproduction

A single organisms produces offspring identical to itself

Homeostasis

Ability to keep a stable internal environment despite external conditions

Metabolism

Combinations of chemical reactions through which an organisms builds up and breaks down materials

Organism

Any living thing

• All living things are called organisms

Cells

Smallest living unit

• All living things are made of cells

Unicellular organisms

Organisms made up of one cell

Multicellular organisms

Organisms made up of two or more cells

Law

Statements based on repeated observations or experiments that describe or predict a natural phenomena

Theory

A structural explanation of a group of facts or phenomena in the natural world that often incorporates a scientific hypothesis and scientific laws

Chemical reactions

When one or more substances changes to another substance

• Involves making or breaking bonds between molecules or atoms

• Energy is absorbed or released in the process

• Chemical reactions require energy to get started

• Amount of energy varies depending on the chemical reaction

Activation energy

Amount of energy required to start a chemical reaction (E_A)

Catalyst

Chemical substance that speeds up the rate of a chemical reaction and lowers activation energy

Enzyme

Proteins that act as biological catalysts in living things

• Virtually all biological reactions require enzymes

• Not destroyed or used up in reactions

• Enzymes are specific to the reactions they catalyze

• Substrates

Substrates

Substance on which an enzyme acts

• Enzyme must “fit” with substrate

• Enzyme substrate complex

Enzyme inhibitors

Molecules that bind to enzymes to slow down or completely stop an enzyme from catalyzing reactions

• May be temporary or permanent

• Can block activation site or change enzyme’s shape

Enzyme activators

Molecules that bind to enzymes to make them more efficient or help them bind to substrates

Why is Carbon important?

1. Carbon atoms have 4 valence electrons allowing them to form strong covalent bonds with many other elements

   • Hydrogen, oxygen, phosphorous, nitrogen, and sulfur

2. Carbon atoms easily bond to other carbon atoms giving them the ability to form chains

   • Can make both large and small molecules

Carbohydrates

Functions: energy (stored or immediate), structural material, support, protection

Lipids

Functions: store energy, biological membranes, temperature regulation, waterproofing, chemical messages

Proteins

Functions: regulate cell processes, structural material (hair, nail, etc.), transport substances, fight diseases, act as enzymes

Nucleic acids

Functions: store and transfer genetic information in cells

Ecology

Study of the interactions between organisms and non-living components of their environment

• Measuring and observing interactions

• Observing patterns

Independence

How different species rely on each other and the non-living components of their environment

• Survival depends on interactions

• Any changes in environment spreads through interactions

Biosphere

Consists of all life on Earth and all parts of the Earth in which life exists including land, water, and the atmosphere

• Broadest level of organization

Biome

A group of ecosystems that share similar climates and organisms

• Ex: rainforests, deserts, grasslands

Ecosystem

All of the organisms and the non-living environment in a particular place

• Ex: pond, lake, ocean, garden, field

Community

All of the living organisms in an area (different populations of individuals)

Population

A group of individuals that belongs to the same species and live in the same area

Species

Group of related organisms that are capable of producing fertile offspring

Primary producers

Organisms that capture energy and use it to make organic molecules

• Photosynthesis

• Chemosynthesis

Consumers

Organisms that gain energy by consuming other organisms or organic waste

• Animals, fungi, some bacteria, some protists

• Classified according to how they acquire energy

• Carnivores

• Herbivores

• Omnivores

• Scavengers

• Decomposers

• Detritivores

Carnivores

Obtain energy by killing and consuming other consumers (animals)

• Lions, wolves, sharks, snakes, etc.

Herbivores

Obtain energy by consuming plants

• Deers, horses, cows, giraffes, etc.

Omnivores

Obtain energy from a variety of foods that include both plants and animals

• Humans, bears, pigs, etc.

Scavengers

Consume carcasses of other animals that have been killed by predators or died of other causes

• Vultures, raccoons, etc.

Decomposers

“Feed” by chemically breaking down organic matter

• Fungi, some bacteria

Detritivores

Animals that feed on detritus particles, dead organisms, and waste

• Earthworms, mites, snails, etc.

Food web

Networks of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

• Outlines more feeding relationships

• More inclusive

Types of species interactions

• Competition

• Predator/prey

• Herbivore/plant

• Symbiosis

Competition

When two organisms attempt to use the same essential resource, which cannot be shared

• Can occur between members of the same or different species

• Direct competition always produces a winner and a loser

• Interspecific competition

• Intraspecific competition

Interspecific cometition

Competition between individuals of different species

• Different species of trees competing for soil, sunlight, and water

Intraspecific competition

Competition between individuals of the same species

• White tail deer competing for a mate

Predation

An interaction in which one animal (predator) eats all or part of another animal (prey)

• Relationship influences population size

• Determine places predators and prey can live

Herbivory

An interaction in which one animal (herbivore) feeds on producers (plants)

• Relationship influences size and distribution of plant populations

Keystone species

A species that plays a vital and unique role in maintaining structure, stability, and diversity in an ecosystem

Symbiosis

A close independent relationship between two species

• Three main types:

  • Mutualism

  • Parasitism

  • Commensalism

Mutualism

Relationship between two species where both benefit from each other

• Honeybees and flowers

Parasitism

Relationship in which one organisms (parasite) lives on or inside another organisms (host) and harms it

• Parasites obtain all nutritional needs from host

• Weaken but do not kill host immediately

• Host is usually larger than parasite

• Fleas, ticks, lice, etc.

Commensalism

Relationship in which one organisms benefits and the other is neither harmed nor helped

• Cape buffalo and egrets

Prokaryotic cells

• Small and simple

• No nucleus

• Lack many membrane bound organelles

• Single-celled

• Ex: bacteria

Eukaryotic cells

• Large and more complex

• DNA stored in nucleus

• Complex membrane bound organelles

• Single-celled and multi-celled

• Ex: plants, animals, fungi, protists, humans, etc.

Plasma membrane

The cell’s outer selective barrier

• Made of phospholipids

• Regulates all materials that enter and exit the cell

  • Oxygen, water, nutrients, waste, etc.

• Found in both prokaryotic and eukaryotic cells

Nucleus

Contains nearly all of the cell’s DNA

• Enclosed in nuclear envelope

• Pores to allow materials in/out

• Nucleolus - dense area where ribosome production takes place

• Found in eukaryotic cells

Mitochondria

Converts chemical energy stored in organic molecules of food into compounds for cellular use, ATP

• Two membranes

  • Cristae - highly folded inner membrane

• Contain their own DNA, instructions for function

• Found in eukaryotic cells

Ribosomes

Small organelles made of RNA and proteins, produce proteins by following instructions found in DNA

• Assembled in nucleolus

• Found throughout cytoplasm or attached to the endoplasmic reticulum

• Found in both prokaryotic and eukaryotic cells

Endoplasmic reticulum

Extensive network of membrane tubules surrounding nucleus

• Smooth ER

  • Lacks ribosomes

  • Synthesis and storage of lipids

• Rough ER

  • Covered in ribosomes

  • Finishes synthesis of proteins produced by ribosomes

• Found in eukaryotic cells

Golgi apparatus (Golgi body)

Modifies, sorts, and packages proteins and other materials from the ER for storage or removal

• Packages materials in vesicles

• Vesicles carried to final destination

• Found in eukaryotic cells

Lysosomes

Small organelles filled with enzymes

• Produced by Golgi apparatus

• Breakdown of carbohydrates, proteins, and lipids for use by rest of cell

• Breakdown old and non-functioning organelles

• Found in animal eukaryotic cells

Cytoskeleton

Network of protein fibers extending through the cytoplasm, maintain cell shape and aid in movement

• Microtubules - maintain shape, aid in cell diviosion

• Microfilaments - produce internal framework for support, aid in cell movement

• Intermediate filaments - anchor nucleus within the cell

• All found in both prokaryotic and eukaryotic cells, except the intermediate filaments which are found in only eukaryotic cells

Cell wall

Support, shape, protection, and prevention uptake of excess water

• Rigid layer outside plasma membrane

• Pores to allow materials in and out

• Found in prokaryotic and eukaryotic cells for plants and fungi

Vacuole

Various functions including storage, digestion, and excretion

• Plant cells

  • Stores water, waste, proteins, and carbohydrates

  • Can expand and shrink depending on contents

• Fungi and animal cells

  • Digestion

  • Smaller in size

• Found in eukaryotic cells (mostly plants)

Chloroplast

Capture energy from the sun and converting it into chemical energy (photosynthesis)

• Two-layer membrane

• Contains chlorophyll and enzymes

• Found in eukaryotic cells, plants and algae

Passive transport

Movement of materials in/out of the cell without the input of energy (no ATP)

• Diffusion

• Facilitated diffusion

• Osmosis

Diffusion

Movement of materials from an area of high concentration to an area of low concentration across the cell membrane

• Driving force behind movement of many substances

• Movement is random

• Continues until equilibrium is reached

• Particles continue to move in each direction equally

• Not all molecules can use simple diffusion

• Requirements: must be small, uncharged, or lipid soluble

• Ex: oxygen, carbon dioxide, lipids

Facilitated diffusion

Type of passive transport that uses transport proteins to move materials across the cell membrane

• Movement from high to low concentration

• For molecules move via simple diffusion

• E: charged particles and large molecules

Osmosis

The movement of water

• Water can move through simple diffusion or facilitated diffusion

• Aquaporins: special protein channels embedded in plasma membrane for the movement of water

  • Movement from high to low concentration

• Net movement of water to balance out concentration of solutes

  • Isotonic

  • Hypertonic

  • Hypotonic

Isotonic

Equal concentrations of solutes and water inside and outside of the cell

• Water molecules move equally in both directions

Hypertonic

Higher solute concentration outside of the cell than inside of the cell

• Water moves outside of the cell

• An excess of water moving out will cause the cell to shrink

• Crenation - the shrinking of animal cells due to water loss

• Plasmolysis - the shrinking of plants cells due to water loss

Hypotonic

Lower solute concentration outside of cell than inside of the cell

• Water moves into the cell

• An excess of water moving in will cause the cell to swell

• Cytolysis - animal cells bursts due to influx of water

Active transport

Movement of materials across the cell membrane against the concentration gradient, requires the input of energy

• Movement of materials from a low concentration to a high concentration

• Carried out by transport proteins

• Two types:

  • Molecular transport

  • Bulk transport

Sodium potassium pump

Transport proteins that move sodium and potassium ions across the plasma membrane

• Molecular transport

• Important for normal cell physiology

• In humans: muscle contractions, nerve impulses, cell communication, etc.

Endocytosis

The process of taking materials into the cell by enclosing pockets in the cell membane

• Bulk transport

Exocytosis

The process of removing materials from the cell using vesicles that fuse with the cell membrane

• Bulk transport

ATP (adenosine triphosphate)

Basic energy source used by all types of cells

• Adenine (nitrogenous base), 5-carbon sugar (ribose), three phosphate groups

• Phosphate groups are key to ATP’s ability to store and release energy

ADP (adenosine diphosphate)

Compound similar to ATP, contains some energy, used to generate ATP with the addition of 1 phosphate

• Adenine (nitrogenous base), 5-carbon sugar (ribose), two phosphate groups

Heterotrophs

Organisms that obtain their energy by consuming other living things

• Consumers (primary, secondary, tertiary)

Autotrophs

Organisms that obtain their energy by making it themselves

• Nearly all life depends on the ability of autotrophs to make food

• Chemosynthesis - process in which chemicals are used to produce energy

  • Mostly bacteria

  • Done by organisms who live in places without the sun

• Photosynthesis - process in which energy from the sun is converted into high energy carbohydrates (sugars and starches)

Photosynthesis

Reactants: carbon dioxide and water

Products: glucose and oxygen

• Light dependent reaction

• Light independent reactions

Light-dependent reactions

Reactions that involve lights and light-absorbing pigments

• Take place in thylakoids

• Water is required (source of electrons and H⁺ ions)

• Oxygen is released (byproduct)

Light-independent reactions (Calvin cycle)

High energy molecules are produced from CO₂ without light

• Take place in stroma

Cellular respiration

Process that releases energy from food in the presence of oxygen

• Food molecules broken down gradually to release energy

• Energy stored in chemical bonds

• Done by both autotrophs and heterotrophs

Three main stages of cellular respiration

1. Glycolysis

2. Krebs cycle

3. ETC and ATP synthesis

Glycolysis

1 molecule of glucose, (6-carbon compound) is transformed into 2 molecules of pyruvic acid (3-carbon compound)

• Takes place in cytoplasm

Krebs cycle

Pyruvic acid is broken down into carbon dioxide in a series of reactions

• Takes place in mitochondria

ETC and ATP synthesis

• Takes place in mitochondria

Fermentation

Breakdown of organic molecules into energy in the absence of oxygen

• Done by yeast, bacteria, fruit, fungi, and animal cells

• Some cells go through fermentation all the time, others only when oxygen isn’t available

• Two common pathways:

  • Alcoholic fermentation

  • Lactic acid fermentation

Alcoholic fermentation

Pyruvic acid is converted to ethyl alcohol and carbon dioxide after glycolysis

• Ex: when yeast cells in dough use up O₂, they ferment giving off CO₂ and causing bread to rise

Lactic acid fermentation

Pyruvic acid converted into lactic acid after glycolysis

• Done by most organisms

• Ex: cheese, yogurt, muscle cells

DNA

• DNA: deoxyribonucleic acid

• Contains genetic instructions

  • Physical characteristics

  • Information for cell activity

• Found in all cells

  • In nucleus of eukaryotic cells

  • In nucleoid region of prokaryotic cells

Chromosomes

Coiled compact structures made of DNA and proteins

• Bundles packages of genetic information

• Duplicated or unduplicated

Histones

Proteins that DNA wraps around to form a chromosomes and keep it safe

Chromatids

One of two identical halves of a duplicated chromosome

• Genetic information on each half is the same (sister chromatids)

Centromere

Region that holds two chromatids together

• Special segment of chromosome

Sex chromosome

Carry genetic coding to determine the gender of an individual, may also carry other genes

Autosomes

Carry genetic coding for everything except gender

• Humans have 46 chromosomes: 2 sex chromosomes and 44 autosomes

• Every cell has two copies of each autosomes

  • Come about by reproduction

  • One copy from each parent

Homologous chromosomes

Pair of chromosomes, one maternal and one paternal

• Same size and shape

• Same centromere location

• Same band pattern

• Carries same genetic information

Karyotype

Photomicrograph of chromosomes in cells

• Chromosomes are sorted and grouped by homologous pairs

• Matched by length, band pattern, etc.

• Numbered

• Used to determine genetic abnormalities in chromosomes

Mitosis

Eukaryotic cell division

• Prophase

• Metaphase

• Anaphase

• Telophase

  • Cytokinesis