Ch. 4 Fundamentals of Biology

Carbohydrates (sugars)ProteinsLipidsNucleic Acids

Organic Compounds: The Ingredients of Life:

– molecules containing C, H, & O

Make life possible High-energy molecules Energy used to synthesize Energy released in breakdown Four types of organic compounds

Organic compounds

Glucose – metabolized for energy

Starches – long chains of simple sugars used for energy storage

Chitin – skeletal material Cellulose – cell structure

Carbohydrates – sugars

Proteins

Chains of amino acids

Muscles are mostly made up of proteins

Enzymes – catalyze reactions

Structural proteins – skin, hair, skeleton

Hormones

Lipids

Fats, oils, & waxes

Energy storage – more than twice as much as sugar

Water repellant

Buoyancy

Insulation

Hormones

Nucleic Acids Store and transmit the

genetic information of all living things

Long chains of subunits called nucleotides

DNA – instructions for the construction and maintenance of an organism; the complete set is called the genome

The nitrogen bases are sequenced into genes that code for a specific protein

RNA – helps DNA

ATP – the molecule used to store energy; like a rechargeable battery

You use ~ 125 lbs./day

Organisms need to capture, store and use energy

Most organisms use only two sets of reactions

The Fuel of Life

Photosynthesis: Making the Fuel Algae, plants, and some

microorganisms

Capture the sun’s energy and use it to make glucose

The pigment chlorophyll captures the solar energy

We rely on photosynthesis for food and oxygen

Organisms that photosynthesize are called autotrophs (animals that make their own food)

Plants on land; bacteria and algae in the ocean

Chemical Equation for Photosynthesis

Both autotrophs and heterotrophs Releases the energy from org. compounds

Reverse of photosynthesis Organic matter (glucose) + O2 H2O + CO2

(Similar to burning wood or oil) Chemical energy captured in ATP Aerobic – uses oxygen, more efficient Anaerobic – does not use oxygen, less efficient

Respiration: Burning the Fuel

Most of the glucose is used for fuel or converted into other types of org. compounds

The organic matter autotrophs make is called primary production

Used by the organism for growth and reproduction

Autotrophs are animals that make their own food (also called producers)

Primary Production

Vitamins, minerals and other substances are needed to convert glucose into other

org. compounds Nitrogen for proteins & nucleic acids

Phosphorus for nucleic acids Silica (SiO2) to make shells Iron – necessary, but a limited resource

in the ocean

The Importance of Nutrients for plant growth in the ocean

Organic compounds are organized into functional units that are alive

4.2 Living Machinery

1. Cells and Organelles

Cell – basic unit of life

All organisms are made of cells

Wrapped in a cell membrane

Cell is filled with jelly-like cytoplasm

Organelles have specific jobs in the cell

A. Structurally Simple Cells: ProkaryotesProkaryotes are

primitive cells Ancient, simple, small No membrane-bound

organelles

Bacteria Prokaryotes have few

structures: Cell wall – support Ribosomes – assemble

proteins DNA – loose in the

cytoplasm Flagella – locomotion

2. Structurally Complex Cells: Eukaryotic

Eukaryotic cells are organized and complex

Larger than prokaryotes

Have specialized organelles: Nucleus – contains

chromosomes (DNA) Endoplasmic reticulum

– make proteins and other org. molecules for the cell

Golgi apparatus – package and transport molecules

Mitochondria – respiration center to provide energy

Flagella and cilia – for movement

Chloroplasts –photosynthesis center

Cell wall - support

Only in plant & algal cells

1. A cell is self-contained and can carry out all the functions necessary for life

Unicellular – all prokaryotes and some eukaryotes

Multicellular – most eukaryotes Human body has 100,000,000,000,000

cells In multicellular organisms cells

specialize to perform different tasks for the organism

Levels of Organization

Cells that act together for a specific job are called tissues Muscle, nervous, bone, blood,

epithelial Tissues are organized into organs to

carry out specific functionsLiver, kidney, heart, skin, brain

Organs act together in an organ systemSkeletal, muscular, excretory,

endocrine, digestive

Levels of Org. Continued

Species – one type of organismBlue mussel

Population – a group of one species A bunch of blue mussels

Community – several different populations that live and interact in an areaBlue mussels, crabs, barnacles, & chitons living

on a rock Ecosystem – the communities living together

with the physical environment Living on a rocky shore with seawater, air,

temperature, sunlight, etc.

2. Organization exists outside the individual organism

Marine organisms must cope with different problems than on land

and have evolved ways to adapt to their marine habitat

Most important is maintaining homeostasis (Keeping their internal condition normal regardless of the external condition)

4.3 Challenges of Life in the Sea

Marine organisms are immersed in a medium – sea water – that can greatly affect their cell function

Enzymes and organic molecules are sensitive to ion concentration (salinity)

A. Salinity

Diffusion

Dissolved ions move around in water

Random movement spreads ions out in an even distribution

Results in diffusion – movement from high to low concentration

Diffusion Cont.When concentrations

are different inside and outside a cell, substances will move in/out by diffusion

Salt from seawater will diffuse into the cell

Nutrients will diffuse out of the cell

The cell membrane blocks diffusion It’s selectively permeable – it allows

only some substances to go in/out Water is a small molecule and can

fit through the cell membrane ** Always diffuses from high to low

concentration

Diffusion Cont.

If a cell has more solutes inside than outside, water will stream in and swell the cell

If the seawater has more salt, water will leave and the cell will shrivel

This diffusion of water is called osmosis

Osmosis

Cells may need to move materials against diffusion (low high)

-e.g. expelling extra salt or taking in more sugar

That requires ENERGY!!!

Active transport – proteins in the cell membrane pump materials using ATP

1/3 of the cell’s energy is spent on this

Active Transport

Marine organisms have adapted ways to balance water and salt

A. Osmoconformers –their internal concentrations change with the salinity of the seawater

Live in a narrow range of salinity

Regulation of Salt and Water Balance

– control internal concentrations to avoid osmotic problems

Can tolerate changes in salinity better Can change their internal concentrations to

match the seawater Salt water fishes lose water by osmosis¨ Drink water or reduce urine amount to

replace lost water Excrete excess salts in the urine or through

the gills

Osmoregulators

Marine Fish VS Freshwater Fish

Freshwater fishes gain water by osmosishttps://www.youtube.com/watch?v=D3voCy12AnY

Ectotherms – “cold blooded” lose their heat to the seawater

Endotherms – “warm blooded” retain heat and keep their body temp higher than the water

-Mammals, birds, and some large fishes

Poikilotherms – body temp changes with the temp of the seawater

Incl. all ectotherms & endothermic fishes

Homeotherms – keep internal temp the same, regardless of outside temp

Go back and draw a picture next to each of the last 6 definitions:

OsmoconformerOsmoregulatorEctothermEndothermPoikilothermHomeotherm

Heat and materials exchange across the surface of an organism

The surface-to-volume ratio (S/V ratio) determines how rapidly this happens

As organisms get larger the volume grows faster than the surface area

Small organisms rely on diffusion Large organisms respiratory and excretory

systems

Surface-to-Volume Ratio

A species must reproduce or vanish from the planet Produce a new offspring Pass on the genetic information

A. Modes of Reproduction Cells reproduce through cell division Cell fission in prokaryotes; mitosis in

eukaryotes Results in identical daughter cells

4.4 Perpetuating Life (Reproduction)

Asexual ReproductionNo partner Offspring are genetically

identical – clones Most single-celled

organisms reproduce this way, & some multicellular organisms do

1. Fission-some sea anemones will split in half, making two smaller ones

2. Budding-Some sponges break off to become separate individuals

Union of two separate gametes (sex cells) from two parents

Ovaries – female gonads that produce eggs

Testes – male gonads that produce sperm

Meiosis divides the chromosomes in half; Fertilization combines them to form a full set again

A fertilized egg is called a zygote. It has DNA from both parents

Sexual Reproduction

This genetic recombination causes variation in the offspring and is the greatest advantage of sexual reproduction

The zygote divides by mitosis and eventually forms an embryo

May pass through a larval stage on the way to adulthood

Sexual Reproduction Cont.

The goal of reproduction is to pass on the genes Varying reproductive strategies to get the same

result Broadcast spawning – release millions of eggs

and sperm into the water No parental care, most die Have few offspring and invest more time and

energy into their survival Some use sexual and asexual reproduction Some species are hermaphroditic, both sexual

organs

Reproductive Strategies

The vast diversity of organisms in the ocean came through millions of years of evolution

The gradual alteration of a species’ genetic makeup

4.5 The Diversity of Life in the Sea

Individual organisms show variation in how they: Find food, avoid being eaten, reproduce, find mates,

metabolize, etc. The best-adapted produce more offspring than the

others This process is called natural selection As their genes get passed on the favorable

traits become more common The population’s genetic makeup changes over

time as it adapts to its environment Populations either adapt to the changes in the

environment or become extinct

A. Natural Selection and Adaptation

To discuss the huge variety of life forms we must first classify them

1. The Biological Species Concept Species- A population with common

characteristics that can successfully breed with each other (fertile offspring)

If two populations cannot interbreed they are reproductively isolated

B. Classifying Living Things

Biological NomenclatureOrganisms are

identified with a two-word name -

Genus and species Blue whale –

Balaenoptera musculus

Fin whale – Balaenoptera physalus

Minke whale – Balaenoptera acutorostrata

Latin or Greek is used for naming Common names are confusing, scientific names are used worldwide to precisely identify a species

Phylogenetics: Reconstructing EvolutionOrganisms are grouped

according to their relatedness

Related organisms share an evolutionary history, or phylogeny

They share a common ancestor

Look at fossil record, anatomy, reproduction,

embryological development, DNA, behavior, etc.

The Tree of Life Classifications have

changed over time Started with two

kingdoms – Animalia and Plantae

Then five kingdoms – added Fungi, Monera, & Protista

Then three domain system

DomainKingdomPhylumClassOrderFamilyGenusSpecies