The LAST LOOK Biology EOC Review Guide

The Bare Necessities you need to remember

***********************************************************************************

Organic Molecules – compounds containing carbon bonds

Carbohydrates (sugars) – pasta, bread, fruit; source of energy
Simplest is a monosaccharide or simple sugar (glucose, fructose)
Two monosaccharides make a disaccharide (sucrose – table sugar)
Chains of monosaccharides make polysaccharides (starch, cellulose, glycogen)

Proteins – building blocks of amino acids; amino acids combine to form proteins

Lipids (fats) – do not dissolve or break apart in water; store energy from excess food

Nucleic acids – information passed from one generation of cells to the next (genetic information) is stored in nucleic acids

Assembled from individual units called nucleotides – each nucleotide is made up of a 5-carbon sugar, phosphate group, and nitrogen base
Two most important nucleic acids are DNA and RNA – genetic info stored in DNA is transferred by RNA (carries information from DNA to ribosomes) to direct production of proteins.

***************************************************************************************************

Cell Organelles

Nucleus – Control center of the cell; contains the DNA

Cell membrane – thin layer surrounding cell; semipermeable so that some substances can pass through to take in nutrients and dispose of waste

Cytoplasm – jellylike material located between cell membrane and nucleus

Ribosomes – where proteins are made in the cell

Endoplasmic reticulum (ER)– system of membranes and sacs that act like a highway along which molecules move from one part of the cell to another

Golgi apparatus – proteins move from ER to Golgi apparatus before they are transported to different parts of the cytoplasm

Mitochondria– site of chemical reactions that transfer energy from organic compounds into a substance called ATP (this molecule stores energy in its chemical bonds); When ATP bonds are broken, they release energy and ADP is formed – the energy is then available to meet the needs of cells

Lysosomes – digestive system of the cell; small spherical organelles (rare in plant cells)

Plants only:

Cell wall – outer layer surrounding cell membrane; makes cell rigid and protects

Vacuole – fluid-filled organelle that store enzymes and wastes; can be very large

Plastids contain pigments – chloroplasts is a type of green plastid that absorbs the sun’s energy so plants can make food

**************************************************************************************************

Two major group of Organisms

Eukaryotes – organisms whose cells have a membrane-bound nucleus and organelles; examples are animals and plants

Prokaryotes– organisms do not contain membrane-bound organelles; examples are bacteria and blue-green algae

Cellular Organism Hierarchy

Cell – tissue – organ – organ system - organism

Homeostasis – ability of an organism to regulate internal conditions despite changes to outside environment (balance); temperature, pH, metabolism

Diffusion

Transportation in and out of cells
Movement of particles from an area of higher concentration to an area of lower concentration
Particles move from areas where they are more crowded to areas where they are less crowded
The most important substance to pass through the cell membrane is water. This type of diffusion is called osmosis.

Enzymes

Organic catalyst that controls the rate of chemical reactions within cells; enzymes are proteins (made from amino acids)
Without enzymes many chemical reactions that occur in living things would not be able to occur or would occur too slowly for organisms to survive
Surface of an enzyme has a distinct shape that allows it to binds with to another enzyme – like puzzle piece or a lock and key.

****************************************************************************************************

Respiration

Aerobic Respiration – requires oxygen; cellular respiration is aerobic
Anaerobic Respiration – does not require oxygen; begins with glycolysis and followed by fermentation

Photosynthesis

Process by which plants produce foods in form of simple sugars and then converts them to complex carbohydrates which store energy
Chemical reaction in which CO2 from air combines with water in the presence of sunlight to produce organic compounds and O2

Autotrophs – organisms that produce food, such as plants

Heterotrophs – organisms that cannot produce their own food (animals)

****************************************************************************************************

DNA Structure

Made up of individual nucleotides
Each nucleotide in DNA has one of 4 possible nitrogen bases:
A – adenine
T – thymine

A pairs with T

G – guanine
C – cytosine

C pairs with G

Nucleotides from long chains and two chains twist like a spiral staircase (double helix) to make one molecule of DNA

DNA replication

Total number of cells must increase in order for an organism to grow

Process by which a cell forms a new cell is known as cell cycle

When a cell divides an identical copy of DNA is passed alone to each new daughter cell.

RNA

Single strand instead of a double strand like DNA
Has uracil (U) base instead of thymine (T)
3 main types:
mRNA (messenger) – carries instructions from DNA; instructions arranged in sequences of 3 nucleotides called condons(codes for a particular amino acid)
tRNA (transfer) – carries amino acids to ribosomes
rRNA(ribosomal) – part of the structure of ribosomes

Chromosomes

A molecule of DNA can be very long – in order to fit inside the nucleus, it wraps around proteins and becomes tightly packed into structures called chromosomes
Every species has a certain number of chromosomes unique it its species – humans as 46 or 23 pairs
Each sections of a chromosome is called a gene and codes for specific trait for that organism – each chromosome contains many genes.
Main function of genes is to control production of proteins (proteins determine the characteristics of an organism)

***************************************************************************************************

Reproduction

Asexual – producing offspring by a single parent; offspring are genetically identical to the parent

Ways cell divide in asexual reporduction

Binary fission – cell divides and each part receives one copy of genetic information; used in asexual reproduction; example – bacteria and other prokaryotic cells

Eukaryotic cells division is more complex – 5 main stages:

Cell grows and carry out routine functions
Cell’s chromosomes are copied
Cell prepares nucleus to divide
Nucleus divides into two in a process called mitosis. Mitosis ensures that each new cell receives a copy of every chromosome.
Once mitosis is complete, the cell divides into tow cells that are identical to the parent cell.

Sexual – two parent cells join to form a new individual

Sex cells (gametes) are different from other body cells
They are haploid which means they have half the number of chromosomes present
Use a process called meiosis that cuts the number of chromosomes in half.
When sex cells are formed, the chromosomes are copied once and then the nucleus divides twice.
The resulting 4 cells have half the number of chromosomes found in a normal body cell.
When sex cells combine during a process known as fertilization, the resulting cell has a complete set of chromosomes – half from each sex cell.
The offspring are diploid – means they have two copies of each chromosome
The offspring of sexual reproduction have a mix of the genetic material from both parents and are not identical to either.

***************************************************************************************************

Patterns of Inheritance

Traits

Dominant allele is expressed in a physical characteristic. Written with an uppercase letter. (BB – homozygous or Bb - heterozygous)
Recessive allele is not expressed in a physical characteristic. They are expressed when there are no dominant alleles present. Written with a lowercase letter (bb – homozygous).

Genotype – the alleles that an organism inherits from its parents make up the organism’s genotype or genetic composition; examples are BB, Bb, bb
Phenotype – even though there can be 3 different genotypes, there are only 2 phenotypes – the physically displayed trait such as color.

Mendelian Genetics

Gregor Mendel – Austrian monk in mid 1800’s used pea plants to discovery many of the things that lead to our current understanding of genetics.

Punnett Squares are diagrams used to identify possible combinations of dominant and recessive alleles in offspring.

Pedigree is a family record that shows which members inherit a specific trait over generations. Square boxes are male; circles are females; colored squares/circles have the disorder and half-colored squares/circles carry the trait.

Sex-linked traits are carried on sex chromosomes (23rd pair); they usually only appear in males – color blindness is an example.

***********************************************************************************************

Genetic Technology (Biotechnology)

Human Genome Project completed in 2003 (started in 1990) mapped the 30-40 thousand genes in human DNA.
Cloning – genetically identical organisms created from a single cell. Dolly, the sheep is most well-known example.
Genetically Modified Foods– engineered to grow larger, faster, and more disease resistant
Genetic Engineering – genes or pieces of DNA are taken from one organism and transferred to another organism; when the DNA pieces combine, they become recombinant DNA.
Stem Cell Research –human body produces billions of new cells every day and most have specific jobs; early in development they become specialize, such as blood, muscle, or brain cells; some cells are not specialized and can develop into a variety of cells – these are called stem cells.Researchers want to use these cells to replace cell damage from injury or disease. Two sources of stem cells – embryonic or adult tissue.

***************************************************************************************************

Evolution– process of change over time

Species – group of organisms that can interbreed to produce fertile offspring.
Variations – differences in characteristics that occur among in organisms
Adaptation – trait that improves and organism’s chance for survival and reproduction
Mutations – change that occurs in DNA sequence; usually an error

Natural selection – theory proposed by Charles Darwin that states that organisms best suited to their environments as a result of favorable characteristics survive and reproduce.

Evidence for evolution

Fossils – preserved remains of organisms

Comparative morphology – structures of living things are compared to understand the development and relationship among species

Analogous structures – serve same purpose in different species but evolved independently – structures did not evolve from the same structures in a common ancestor
Homologous structures – similar body parts found in different species

Embryology – study of early stages of life, before birth. Many organisms are similar in appearance and have common features as embryos but vary significantly as adults

************************************************************************************

Classification – systematic grouping of organisms based on common characteristics.

Taxonomy – science of identifying, classifying, and naming living things

Carolus Linnaeus Swedish, 700’s) developed the hierarchical system used today.

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species – smallest

Organisms are universally named using genus and species (Latin is the language used)

Dichotomous Key uses several pairs of statements. Based on observation, you choose a statement and proceed to the next pair of observations or the name of the organism

******************************************************************************************

Protists

Protozoans: animal-like

Zooflagellates: swim with a flagellum – long projection that looks like a whip
Sarcodines: move using projections from the cytoplasm call pseudopods (example: amoebas)
Ciliates: have short hair-like projections called cilia(used for movement and feeding)

Algae: plant-like; contain chlorophyll and conduct photosynthesis; can move around like animals (ex. Diatoms, green, red, brown algae, euglena, dinoflagellates)
Fungus-like protest: slime and water molds

Plants

All are multicellular autotrophs
Cells are eukaryotic
Have chloroplasts and cell walls

Nonvascular – lack vascular tissue; examples – mosses, liverworts, hornworts
Vascular – have system of tubes that transport food, water, and minerals in a plant; vascular tissue provides strength and stability enabling vascular plants to grow tall; examples are palm trees, rose bushes, bamboo

Life cycle of plants

Sporophyte – plant has a complete set of chromosomes and is diploid; produces spores (tiny cells that grow into new organisms); spores develop into . . .
Gametophyte – haploid (has only ½ number of chromosomes as sporophyte); plant produces gametes (egg and sperm cells)
Sperm cell and egg cell join during fertilization to form a zygote (fertilized egg) – zygote develops into a sporophyte and cell begins again.

Seed Plants

Gymnosperms

produces cones: both male – produce pollen which become sperm cells; and female gametophyte is produces in ovule
usually have needle-like leaves (reduce water loss)
examples are pine trees
during fertilization, pollen falls from male cones onto a female cone; wind usually carries the fertilized seed to location suitable for growth

Angiosperms

Produces flowers and has seeds enclosed in fruits
Reproductive structure is a flower
Male reproductive part is the stamen and female part is called pistil
Pollen is carried by wind or animals
Once fertilized, the ovary becomes the fruit

Plant Adaptations

Roots- anchors plat in ground to absorb water and nutrients from soil
Stems- support plant and transport material
Leaves- site of photosynthesis

Animal Adaptations

Predator adaptations increase animal’s chances of catching prey (food); the speed of a lion is an example.
Prey adaption help an animal keep from being killed.
Mimicry is an adaptation that helps animals look more dangerous to other animals.
Camouflage – animals blend in with their surroundings to hide from predators

Coevolution: process in which 2 species evolve in response to change in each other; likely to occur when 2 species have a close relationship and are dependent on each other; example – plants and their pollinators

***********************************************************************************

Pathogens

Robert Koch (German; 1880’s) developed a theory that diseases are caused by a pathogen – organism that causes a disease

Bacteria

Unicellular
Some are helpful (live in intestines and help with digestion; make food – yogurt, bread)
Others cause strep throat, ear infections, tuberculosis, etc
Can damage cells and tissue or release toxins (poisons)

Viruses

Genetic material surrounded by a protein shell
Smaller than bacteria
Have some features of living things, but cannot survive without a host
Can only reproduce inside living cells
Examples – chicken pox, rabies, measles

Fungi

Eukaryotic heterotrophs
Feed on dead or decaying organic matter
Grow best in dark, moist climates
Examples – ringworm, athlete’s foot

Protist

Cause malaria, African sleeping sickness

Life Functions in Mammals

Feeding
Respiration and circulation
Homeostasis
Movement
Nervous System
Reproduction – placental (mothers carry young in uterus until they develop enough to live outside her body; marsupials (have a short development inside mother and then continue development in pouch outside the mother); monotremes – lay eggs

***********************************************************************************************

Factors Affecting Health and Disease

Noncommunicable disease – cannot be transmitted from one person to another

Communicable disease – can be spread from one person to another; contagious if it spreads quickly and easily from one person to the next.

Genetics – some disease can be passed from one generation to another (noncommunicable); examples are hemophilia, cystic fibrosis

Parasites – microorganisms; live on or in another organism and feeds off it; examples of human diseases caused by parasites – malaria, roundworm

Toxins – poisonous substance; botulism (food poisoning) and fungi

Immune Response – 3 lines of defense

Skin – acts as a barrier
Injured cells release chemicals that increase blood flow to an invaded region such as cut or scrape – the blood bring white blood cells that attack pathogens
Attacking specific pathogens with T and B cells

Nutrition

Vitamins – substance essential to body in small amounts; obtained naturally from plant and animal foods; required for normal growth and activity; A, D, E, K, B, & C
Minerals – nutrients not made by living things; obtain by eating plants that have absorbed minerals through their roots and animals that have eaten the plants; calcium, iodine, iron, potassium

***********************************************************************************************

Levels of Organization

Ecosystem – groups of organisms living together and interacting with each other and the environment around them; examples: desert, rainforest. Tundra, temperature forest
Ecology – scientific study of interrelationships of organisms and their environments
Stability of ecosystem is dependent on interactions of populations (group of individuals of the same species living in the same area) in an ecosystem
Community – interacting populations

3 kinds of Symbiosis – permanent relationship between two different types of

organisms

Mutualism – both organisms benefit one another; example:clownfish that dwell among the tentacles of Ritteri sea anemones. The fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protect the clownfish from its predators. A special mucus on the clownfish protects it from the stinging tentacles
Commensalism–one organism benefits from the other; the other organism is neither harmed nor helped; example:Crabs and Shrimps live with anemones in tropical waters, for the purposes of protection from predation.
Parasitism– one organism benefits and the other is harmed; example:tick feeding on the blood of its host

Predation – A predator (animal that eats other animals) feeds on prey (an animal being killed or eaten); predators are important to control sizes of prey populations; if predators decrease, prey animals increase often to higher numbers than an ecosystem can support

Practice Quiz: Examples of Symbiosis

****************************************************************************************************

Factors Limiting Populations

Abiotic factors – things in environments that are not alive; examples include light sources, temperature, amt. of precipitation, type of soil, etc.

Biotic factors – things in environments that are living; all organisms

Limiting factors – environmental things that can affect size of populations; is there enough water, food, sunlight, oxygen, etc

Carrying Capacity – largest population that a given environment can support over a long period of time.

Cycling Matter