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Biology EOC Review

Biology EOC Semester 1 and 2 Review

Part 1: Characteristics of Life

  • Made of cells
  • Reproduction
  • Based upon a universal genetic code
  • Grow and develop
  • Obtain and use energy
  • Respond to their environment
  • Maintain a stable internal environment (homeostasis)
  • As a group, change over time (evolve)

Part 2: Cell Structure and Function

  • Cell theory
  1. All living things are made of one or more cells
  2. Cells are the basic units of structure and function in organisms.
  3. All cells arise from existing cells.
  • Cell membrane
  1. Lipid bilayer
  2. Semipermeable membrane
  • Two key types of cell
  1. Prokaryotic—no true nucleus or membrane bound organelles
  2. Eukaryotic
  • Transport across a cell membrane
  • Passive transport—movement from high to low concentration without use of energy. Examples include diffusion and osmosis (diffusion of water across a selectively permeable membrane). Facilitated diffusion uses transport proteins to carry the substance across the membrane; no energy is required for this, either.

Diffusion
Diffusion or passive transport is the movement of materials from a region of higher to a region of lower substance concentration. The diagram at the right shows the movement of molecules from higher concentration on side A to a lower concentration on side B. /

  1. Active transport—use of energy to move materials against the concentration gradient; carrier proteins can be used for this as in the sodium-potassium pump; endocytosis moves materials into a cell and exocytosis moves materials out of the cell.

Active Transport
In active transport, molecules move from a region of lower concentration to a region of higher concentration. As this process does not naturally occur, the cell has to use energy in the form of ATP to make active transport occur. /

  • Cell components—contain parts called organelles that are used to provide the framework and functional units of the cell

A Typical Animal Cell
Some Cell Organelles
Cell Organelle / Function
nucleus / control center of the cell
contains DNA which directs the synthesis of proteins by the cell
mitochondrion / carries on the process of cell respiration converting glucose to ATP energy the cell can use
endoplasmic reticulum / transport channels within the cell; can be rough with ribosomes on it or smooth
ribosome / found on the endoplasmic reticulum and free within the cell
responsible for the synthesis of proteins for the cell
cell membrane / selectively regulates the materials moving to and from the cell
Golgi apparatus / final processing of cell products
food vacuole / stores and digests food
contractile vacuole / pumps out wastes and excess water from the cell
chloroplast / found in plant cells and algae; carries out the process of photosynthesis
cell wall / surrounds and supports plant cells, fungi, bacteria, and some protists; not found in animal cells
  • Energy Production
  • Photosynthesis—in chloroplast

Light Energy + 6CO2 + 6H2O  C6H12O6 + 6O2

  1. Cellular respiration—in mitochondrion

C6H12O6 + 6O2 6CO2 + 6H2O + ATP (energy)

  1. Release of energy from ATP is used to power chemical reactions needed to carry out life activities.

ATP  ADP + P + energy

  • Levels of organization in multicellular organisms
  • organelles
  • cells
  • tissues
  • organs
  • organism
  • Viruses
  • Non-living—viruses do not demonstrate the characteristics of life because they cannot replicate without the use of a host cell; viruses are noncellular
  • Structure—composed of an inner core of nucleic acid (DNA or RNA) and an outer protein coat (capsid); some also have an additional outer envelope and some surface proteins; some viruses are retroviruses which use reverse transcriptase to make DNA from the RNA template; AIDS is a retrovirus
  • Cause of many diseases such as AIDS, Polio, Mumps, Herpes

  1. Viruses have two cycles; they can be in the lysogenic cycle causing no signs of illness and then go into the lytic cycle and cause an outbreak of the disease. AIDS and Herpes act like this.

  • Cell reproduction or division (Mitosis)—A. Cell starts with 2N (diploid) number of chromosomes, B. the chromosomes (contain DNA) are replicated to become 4N, C. the chromosomes and cytoplasm divide to produce 2 smaller 2N daughter cells.

Part 3: DNA Structure and Function

  • DNA is the symbol for deoxyribose nucleic acid.
  • In eukaryotic cells it is found in the nucleus of the cell; along with proteins,

it makes up the chromosomes.

  • Genetic information is stored in the DNA which is located in the nucleus.
  • The 5 carbon sugar of DNA is where it gets its name from: deoxyribose.
  • DNA is made up of many nucleotides. Each nucleotide consists of three parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base.
  • The structure, which was discovered by James Watson and Francis Crick (Watson andCrick), is a double helix. It is like a twisted ladder.
  • The genetic code is written in the order of the nitrogen bases. The four bases are:

Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). The bases pair together as follows: A-T and C-G

  • The process of copying DNA is called replication. This occurs in both mitosis (cell division) and meiosis (gamete formation).
  • RNA (ribose nucleic acid) is used to carry the DNA message from the nucleus to the ribosome of the cell where the instructions are carried out (the protein is made). The specific type of RNA that does this is messenger RNA or mRNA. RNA is different from DNA because it is single stranded and uses Uracil (U) instead of Thymine (T).
  • The process of copying the code from the DNA to mRNA is transcription.
  • For the code to be carried out, the mRNA attaches to a ribosome in the cytoplasm. Another type of RNA, transfer RNA or tRNA, brings amino acids to the ribosome. They are attached in the order specified by the codons (3 nitrogen bases) to make a protein.
  • The process of decoding the message on the mRNA into a protein is called translation.

Decoding Chart

You read the chart from left to right; for example, GGC AAU would decode to Gly, Asp

  • DNA fingerprinting can be used as an identification tool for people. It is much more accurate than a traditional hand fingerprint. When a DNA fingerprint is made the following steps are taken: collection of a sample of DNA, cutting of DNA into fragments with restriction enzymes, separation of DNA into fragment by electrophoresis on a gel plate, preparation of the actual fingerprint.

DNA Electrophoresis

  • Example of DNA fingerprints to study:

Which child is not the biological child of both parents?

Based upon the following DNA evidence, who committed the crime?

  • Mutations—a change in the DNA of a gene
  • Gene mutations—affect only a gene; if it affects only one nucleotide, it is referred to as a point mutation.
  • Chromosomal mutations—affect larger segments of a chromosome
  1. Significance of mutations—rare because of cell’s self-correcting mechanisms; can lead to cancer by changing genes that lead to regulation of cell cycle; production of faulty proteins can lead to genetic disorders; can lead to resistance of bacteria to antibiotics and insects to pesticides

Part 4: Classical Genetics

  • Gregor Mendel is considered to be the father of genetics.
  • Mendel’s Laws
  1. Law of segregation—alleles of the same generation segregate during gamete formation.
  1. Law of Independent Assortment--the law of independent assortment; during gamete formation the segregation of the alleles of one allelic pair is independent of the segregation of the alleles of another allelic pair
  • Some Language of genetics:
  • Monohybrid cross.

Cross involving parents differing in only one trait.

2. Dominant trait.

A trait expressed preferentially over another trait.

3.Recessive trait.

The opposite of dominant. A trait that is preferentially masked.

4.F1 generation.

Offspring of a cross between true breeding plants.

5.F2 generation.

Offspring of a cross involving the F1 generation.

6.Phenotype.

The physical appearance of an organism with respect to a trait, i.e. yellow (Y) or green (y) seeds. The dominant trait is normally represented with a capital letter, and the recessive trait with the same lower case letter.

7.Genotype.

The genetic constitution. Yellow seeds are dominant, but yellow seeded plants could have a genotype of either YY or Yy.

8.Alleles.

The different forms of a gene. Y and y are different alleles of the gene that determines seed color. Alleles occupy the same locus, or position, on chromosomes.

9.Homozygous.

Both alleles for a trait are the same. They can be homozygous dominant (YY), or homozygous recessive (yy).

10.Heterozygous.

Differing alleles for a trait, such as Yy.

11. Dihybrid cross

Cross between parents involving 2 different traits

  • Monohybrid cross
  • Dihybrid cross

Female Gametes
GW / Gw / gW / gw
GW / GGWW
(Yellow,
round) / GGWw
(Yellow,
round) / GgWW
(Yellow,
round) / GgWw
(Yellow,
round)
Male / Gw / GGWw
(Yellow,
round) / GGww
(Yellow,
wrinkled) / GgWw
(Yellow,
round) / Ggww
(Yellow,
wrinkled)
Gametes / gW / GgWW
(Yellow,
round) / GgWw
(Yellow,
round) / ggWW
(Green,
round) / ggWw
(Green,
round)
gw / GgWw
(Yellow,
round) / Ggww
(Yellow,
wrinkled) / ggWw
(Green,
round) / ggww
(Green,
wrinkled
  • How to determine the gametes in a dihybrid cross:
  • Exceptions to simple inheritance
  1. Incomplete dominance—neither allele shows complete dominance over the other; the resulting heterozygote will show an in between phenotype; ex. red and white “four o’clock”flowers produce a pink hybrid
  2. Codominance—both alleles are dominant; ex. sickle cell anemia; the herozygote contains both alleles; this provides an advantage as these people do not get malaria
  1. Polygenic inheritance—more than one gene controls the trait; ex. eye color, skin color
  1. Multiple alleles—more than two alleles are possible; ex. human blood groups with A, B, and O alleles
  1. Sex-linked inheritance—the trait is carried on one of the sex chromosomes, usually the X; ex. Hemophilia, Color blindness, Duschenne Muscular Dystrophy; usually males inherit the trait more than females because they only have one X chromosome.
  • Meiosis—this process is for gamete (egg and sperm) formation; meiosis occurs only in sexually producing organisms; it starts with a diploid (2N) cell and ends with haploid cells (1N) which are the egg (oocyte) or sperm (spermatid) cells.
  • Crossing over—during meiosis, chromosomes cross over and exchange genetic material; this leads to variation in gene combinations
  • Nondisjunction—during meiosis, the chromosomes do not always separate properly; this can result in the egg or sperms having fewer or more chromosomes than is normal; this leads to diseases such as: Down Syndrome (extra chromosome #21), Turner’s Syndrome (female with only 1X), Kleinfelter’s Syndrome (males with an extra X—XXY). Karyotypes can show this:

Part 4: Evolution

  • Charles Darwin developed the theory of evolution by natural selection.
  • Evolution is a process that where a change is the gene pool occurs over time. The process may be very slow (gradualism) or occur in spurts (punctuated equilibrium).
  • In order for natural selection to occur, the following must happen:

1. Variation in offspring

2. Overproduction of offspring

3. Competition (struggle for survival)

4. Differential survival and reproduction (survival of the fittest)

  • Evolution can occur due to mutations (changes in the structure of DNA) and gene shuffling; these can make an organism better able to survive in its environment. This type of change is called an adaptation. The most important advantage that an adaptation gives a living thing is to help it survive so that it can reproduce. Evolution by natural selection produces organisms that are better adapted to their environment.
  • There is a great deal of evidence for evolution. One example is found in the present with the evolution of bacteria that are resistant to antibiotics—remember the video on the TB in the Russian prisons? Other evidence includes: biochemical similarities in organisms, homologous structures, vestigial structures (structures we have, but no longer use such as the appendix), embryological similarities, and fossils. All of these point to common ancestry.
  • Part of understanding evolution is a knowledge of speciation, the evolution of new species. A species is defined as organisms that can produce fertile offspring—fertile means that they can also reproduce. The horse and donkey are not members of the same species because their offspring, the mule, is not fertile—cannot produce offspring. Speciation usually occurs when a population gets separated (such as geographically by a river or canyon) into two or more groups for long periods of time. During this time each group accumulates mutations that eventually prevent them from being able to reproduce with the other group. This is divergent evolution.
  • Biological fitness refers to an organisms ability to survive and reproduce.

Part 4: Classification

  • Taxonomy—The science of naming organisms. Developed by Carl Linneaus; organisms are grouped by common characteristics and similarities. Now we include genetic similarities, as well. Taxonomic levels include (starting from the most general): Domain, Kingdom, Phylum, Class, Order, Family, Genus, species. (Did King Philip come over for good spaghetti?)
  • Binomial nomenclature—2 naming system; each species has a genus name that is capitalized and a species name that is not. Latin words are used so that scientists understand each other world wide. Organisms with the same genus name show close common ancestry! Example: Canis familiaris (the dog) and Canis lupus (the wolf) are close relatives. The scientific name of an organism includes the Genus and species name; an example is humans are referred to as Homo sapiens.

GROUP NAME / ORGANISM
HUMAN / CHIMPANZEE / HOUSE CAT / LION / HOUSEFLY
KINGDOM / Animalia / Animalia / Animalia / Animalia / Animalia
PHYLUM / Chordate / Chordate / Chordate / Chordate / Arthropoda
CLASS / Mammal / Mammal / Mammal / Mammal / Insect
ORDER / Primates / Primates / Carnivora / Carnivora / Diptera
FAMILY / Hominidae / Pongidae / Felidae / Felidae / Muscidae
GENUS / Homo / Pan / Felis / Felis / Musca
SPECIES / sapiens / troglodytes / domestica / leo / domestica
Scientific Name / Homo sapiens / Pan troglodytes / Felis domestica / Felis leo / Musca domestica
  • In the above chart, you can see that the Lion and House Cat show the closest evolutionary relationship because they are members of the same Genus.
  • Organisms can be identified using a dichotomous key.
  • Organisms are placed into 6 kingdoms: Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia. The kingdoms are placed in 3 domains based upon evolutionary relationships: Bacteria, Archaea, and Eukaryota
  • The presence or absence of a cell wall, as well as its composition, is also important in assigning an organism to a kingdom. Only members of the animal kingdom have no cell wall!
  • Bacteria
  1. Shapes
  1. Disease causing are called pathogens (viruses, some Protista and some Fungi are also pathogens).
  2. Diseases caused by Bacteria
  1. Antibiotics kill bacterial but not viral infections. The picture below shows the effect of various types of antibiotics on bacteria growing in a Petri dish.
  1. Bacteria can also be useful
  2. Decomposers
  3. Digestion
  4. Manufacturing
  5. Food production—yogurts, cheese, etc.
  6. Using E. coli to produce human insulin

Part 5: Body Systems

Part 6: Plants

  • Plants have the following characteristics:

1. Multicellular

2. Eukaryotic cells

3. Autotrophic (make their own food) by photosynthesis

Light + 6CO2 + 6H2O C6H12O6 +6O2

4. Cell wall of cellulose

5. Alternation of generations

Plants have a life cycle in which a haploid plant that makes gametes (a gametophyte) alternates with a diploid plant that makes spores (a sporophyte). This is known as alternation of generations. In nonvascular plants, the gametophyte is dominant and in vascular plants, the sporophyte is larger.

  • Plants are classified by the presence or absence of vascular tissue. This tissue forms “tubes” that carry water and minerals (xylem) and nutrients (phloem).
  • Plants with no vascular tissue are the Bryophytes which are the mosses and hornworts. They must live in a moist environment.
  • Plants with vascular tissue are the Tracheophytes. They have “true” roots, stems, and leaves. Three key structures of tracheophytesa are the roots, stems, and leaves.

1. Roots—anchor the plant in the ground and absorb minerals and water from the ground

2. Leaves—absorbs sunlight for photosynthesis and is the location for that process

  • Cuticle—protective, waxy coating on the epidermis of the leaf
  • Palisade layer—most of the photosynthesis takes place here
  • Stomata—openings in the leaf surface that allow for the exchange of gases; surrounded by guard cells to control opening and closing

3. Stems—to hold the plant upright so that the leaves get sunlight; contain xylem (carries water and minerals up from the roots) and phloem (carries food from the leaves to the rest of the plant).

  • Examples of tracheophytes are the gymnosperms (cone bearing), ferns, and angiosperms (flowers and fruits).

gymnosperm fern angiosperm

“naked seeds”/ moisture needed 90% of all plants

seeds in cones/ for reproduction/ flowers/ fruit/

conifers spores/ no seeds dicots and monocots

  • The flower is the reproductive organ of the angiosperm. The cone is the reproductive organ of the gymnosperm.
  • The process of getting the male gamete to the female ovule is called pollination.
  • Flowers may contain both male and female parts or their can be separate male and female flowers. The following picture shows a flower with both structures: