fundamentals of biology
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Fundamentals of Biology
4.1 The Ingredients of Life
• A. The Building Blocks• 1 Organic compounds – molecules containing
C, H, & O• Make life possible• High-energy molecules Energy used to synthesize Energy released in breakdown• Four types of organic compounds
2 Carbohydrates – sugars
• Glucose – metabolized for energy• Starches – long chains of simple sugars used
for energy storage• Chitin – skeletal material• Cellulose – cell structure
3 Proteins
• Chains of amino acids• Muscles are mostly made up of proteins• Enzymes – catalyze reactions• Structural proteins – skin, hair, skeleton• Hormones
4 Lipids
• Fats, oils, & waxes• Energy storage – more than twice as much as
sugar• Water repellant• Buoyancy• Insulation• Hormones
5 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
B. The Fuel of Life
• 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
1 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 CO2 + H2O → C6H12O6 (glucose) + O2
• We rely on photosynthesis for food and oxygen• Organisms that photosynthesize are called
autotrophs Plants on land; bacteria and algae in the ocean
2 Respiration: Burning the Fuel
• Both autotrophs and heterotrophs do it• 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
3 Primary Production
• 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 also called producers
4 The Importance of Nutrients• 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
4.2 Living Machinery
• Organic compounds are organized into functional units that are alive
A. 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
1. Structurally Simple Cells: Prokaryotes
Prokaryotes 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: EukaryotesEukaryotic cells are organized and complex
Larger than prokaryotesHave 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
Only in plant & algal cells Chloroplasts – photosynthesis center Cell wall - support
B. Levels of Organization1. 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• 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 functions Liver, kidney, heart, skin, brain• Organs act together in an organ system Skeletal, muscular, excretory, endocrine, digestive
2. Organization exists outside the individual organism
Species – one type of organism Blue mussel Population – a group of one species A bunch of blue mussels Community – several different populations that live and
interact in an area Blue 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.
4.3 Challenges of Life in the Sea
• Marine organisms must cope with different problems than on land
• They have evolved ways to adapt to their marine habitat
• Most important is maintaining homeostasisKeeping their internal condition normal
regardless of the external condition
A. Salinity
• 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)
1. Diffusion and Osmosis• Dissolved ions move around in water• Random movement spreads them out in an even
distribution• Results in diffusion – movement from high low
concentration• 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 block 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
It also diffuses from high → low concentration 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• Cells may need to move materials against diffusion (low
high) e.g. expelling extra salt or taking in more sugar Active transport – proteins in the cell membrane pump
materials using ATP1/3 of the cell’s energy is spent on this
2. Regulation of Salt and Water Balance• Marine organisms have adapted ways to balance water and
salt• Osmoconformers –their internal concentrations change with
the salinity of the seawater Live in a narrow range of salinity• Osmoregulators – 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
Freshwater fishes gain water by osmosisDon’t drink water or produce lots of urineSalt absorbed by gills Some marine birds and reptiles have special
glands to get rid of excess salt Most algae have rigid cell walls that resist the
swelling caused by osmotic water gain
B. Temperature
Metabolic reactions speed up/slow down when temperature goes up/down
Metabolic rate doubles every 10oC At extreme temps most enzymes cease to
function Marine organisms are adapted to live in a
temp range Thus determining what regions of the oceans
they live
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 Produce more heat as need to keep their metabolic
activity high Mammals & birds They need to eat more food Insulate their bodies with feathers, hair, and blubber
C. Surface-to-Volume Ratio
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
4.4 Perpetuating Life
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
1. Asexual Reproduction
No partner Offspring are genetically identical – clones Most single-celled organisms reproduce this way Some multicellular organisms do: Some sea anemones will split in half, making two
smaller ones–fission
Some sponges develop growths that break off to become separate individuals – budding or vegetative reproduction
2. Sexual Reproduction Union of two separate gametes 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 This genetic recombination causes variation in the offspring 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
B. Reproductive Strategies
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
4.5 The Diversity of Life in the Sea
• The vast diversity of organisms in the ocean came through millions of years of evolution
• The gradual alteration of a species’ genetic makeup
A. Natural Selection and AdaptationIndividual 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
B. Classifying Living Things
To discuss the huge variety of life forms we must first classify them
1. The Biological Species Concept What is a species? A type of organism? A population with common characteristics
that can successfully breed with each other (fertile offspring)
If two populations cannot interbreed they are reproductively isolated
2. Biological Nomenclature• Organisms 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
Levels of Classification
Domain Kingdom Phylum Class Order Family Genus Species
3. Phylogenetics: Reconstructing Evolution
Organisms 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.
4. 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