Ch. 4 Fundamentals of Biology
Jan 19, 2016
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