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Be able to explain how development, genetics, evolution, and ecology relate to the diversity of life (structures, individuals, species, etc):
· Biology’s core theme is evolution, the idea that the organisms of living on earth today are modified descendants of common ancestors.
· Development and genetics tie in with evolution and ecology, which relate to the diversity of life because any slight altercation of genetics, evolution, and ecology defies the diversity of how the species will develop.
· The hierarchy of life follows as biosphere>ecosystem>community>population>organism>organ system>organ>tissue>cell>organelle>molecule>atom.
Be able to describe some of the fundamental properties of life:
· Species are classified into broader groups known as Bacteria, Archea, and Eukarya.
· There are 7 fundamental properties of life:
1. Complexity and organization - all life replicated through DNA and RNA; all life is composed of cells
2. Ability to respond to stimuli
3. Exhibit homeostasis - regulate body processes
4. Acquisition and use of material and energy - e.g. sunlight to sugar
7. Capacity to evolve
Begin to use the scientific method*
· Scientific method is a method of procedure consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.
· a population consists of all the individuals of a species living within the bounds of a specified area.
· an organ is a body part that carries out a particular function in the body such as the maple leaf of a tree or the heart of a human.
· the fundamental unit of structure and function
· the various functional components in cells such as a chloroplast or mitochondria.
· : the most common form in organisms is negative feedback, negative feedback is the accumulation of an end product of a process slows that process. For example, the cell’s breakdown of sugar generates chemical energy in the form of ATP. Positive feedback is when the end product speeds up its own production for example the clotting of your own blood in response to an injury.
· the idea that the organisms of living on earth today are modified descendants of common ancestors
· a tentative answer to a well framed question, an explanation on trial.
· : a variable (often denoted by x) whose variation does not depend on that of another.
· a variable (often denoted by y) whose value depends on that of another.
Be able to explain why cells are considered living things and subcellular structures are not considered living using the properties of living things.
· The coiling allows the chromatids to become sorted, which allows them to be separated.
Know the multiple functions of cell division
genetically identical daughter cells
Be able to describe the structure of a eukaryotic chromosome
· A non-dividing chromosome is composed of a strand of DNA wound around protein molecules called histones. The DNA will have a series of genes within the chromosome.
Be able to diagram the cell cycle and distinguish the processes of DNA
nuclear membrane disappears and framework of microtubules in formed, spindle fibers also form.
The stage of mitosis or meiosis in which the nuclear membrane disintegrates, the centrioles reach the poles of the cell, and the chromosomes continue to contract.
each chromosome is positioned along central axis of cell known as metaphase plate.
Transcribing the genetic code of DNA into RNA molecules.
RNA following DNA’s instructions for building proteins from amino acids.
the material of which the chromosomes of organisms are composed. It consists of protein, RNA, and DNA.
any cell of a living organism other than the reproductive cells.
· a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.
· The G1 phase, or Gap 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division
· S-phase is the part of the cell cycle in which DNA is replicated, occurring between G1 phase and G2 phase.
· : the cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.
· The spindle-shaped achromatic structure, composed of microtubules, along which the chromosomes are distributed in mitosis and meiosis.
Know that separation of the sister chromatids occurs during Mitosis.
Be able to explain one potential evolutionary pathway leading to mitosis
· One evolutionary pathway of mitosis is these processes may be similar to mechanisms used my ancestral species and thus may resemble steps in the evolution of mitosis from a binary fission like process carried out by very early bacteria.
Be able to explain the experiment demonstrating that the spindle moves chromatids through tubule shortening.
· Two mechanisms, both involving motor proteins, the experiment involved using a pig kidney. The scientists marked a region of the kinetochore microtubules between one spindle pole and the chromosomes by using a laser to eliminate the fluorescence from that region, while leaving the microtubules intact. As the chromosomes moved pole ward, the microtubule segments of the kinetochore side of the mark shortened, while those on the spindle side stayed the same length. Therefore, chromosome movement is correlated with kinetochore microtubules shortening at their kinetochore ends and not at their spindle pole ends.
Know that mitosis in plants is somewhat different than in animals
· All of the stages in mitosis (prophase, metaphase, anapahse, and telophase) are similar in both plant and animal cells except for the cytoplasmic division called cytokinesis.
· In animal cells, cytokinesis occurs when a ring of microfilaments forms along the cell's equator, causing the plasma membrane to pinch, which creates two separate daughter cells.
· In plant cells, cytokinesis occurs when carbohydrate-filled vesicles from the Golgi apparatus line up along the cell’s equator and fuse together to form a new cell wall and a new cell membrane that separates the two new daughter cells. The cell membrane cannot pinch as in animal cells because plants have a stiff cell wall
Be able to explain the control of mitosis through CdK and cyclin
· Cyclins are a family of proteins that control the progression of cells through the cell cycle by activating cyclin-dependent kinase (Cdk) enzymes. There are checkpoints where the cell cycle stops until go-ahead signal is received.
Be able to explain that fungal bodies are composed of hyphae of similar cells and that fungal growth occurs largely without development.
· The bodies of fungi form a network of tiny filaments called hyphae.
· Hyphae consist of tubular cell walls surrounding the plasma membrane and cytoplasm of the cells.
· Hyphae form an interwoven mass called a mycelium due to this formation, a fungal mycelium grows rapidly because its structure maximizes its surface-to-volume ratio, making feeding very efficient.
· Therefore it grows rapidly because of the amount of proteins and other materials that are absorbed.
Be able to explain that slime molds have a unique developmental pattern
· Descended from unicellular ancestors
· Plasmodial slime molds first form a mass called a plasmodium; cytoplasmic streaming apparently helps distribute nutrients and oxygen.
· The plasmodium extends pseudopodia through moist soil, etc as it grows.
· If the habitat becomes dry or there is no food left, the plasmodium stops growing and differentiates into fruiting bodies.
· In cellular slime molds, the feeding stage consists of solitary cells that function individually, but when food is depleted, the cells form an aggregate that function as a unit.
· Cellular slime molds have fruiting bodies that function as asexual reproduction rather then sexual like the plasmodial slime molds.
an organ that raises or separates leaves, exposing them to sunlight
points at which leaves are attached
Be able to explain the basic difference in development between plants (an ongoing process that is indeterminate and modular) and most animals:
The most significant difference in development between plants and animals is pattern formation. Pattern formation occurs in all parts of the plant but is limited to specific locations in animals. Meaning, plant growth occurs throughout their entire life.
Be able to explain that meristems are active sites of cell division and that growth and development occur in cells adjacent to meristems.
· Intermediate growth: growth throughout life
· Meristems can divide when conditions permit, leading to new cells that can elongate
· Apical meristems are located at tips of roots and shoots they provide additional cells that enable growth in cells which is known as primary growth
· Lateral meristems add layers of vascular tissue known as xylem to create a thicker periderm, this is known as secondary growth
be able to explain that animals have complex bodies that are hierarchically organized with numerous organ systems
· Animal form and function are correlated at all levels of organization
· Animal sizes and shapes are a process of evolution
· Cells are organized into tissues
· Different types of tissues form organs
· Groups of organs form organ systems
· 4 types of animal tissue: epithelial, connective, muscle and nervous
each of the branching filaments that make up the mycelium of a fungus
the vegetative part of a fungus, consisting of a network of fine white filaments
he apical meristems on the shoot and root apices in plants that produce plant primary tissues.
Cork cambium is a tissue found in many vascular plants as part of the periderm. The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems.
thimble-shaped mass of cells covering and protecting the growing tip of a root
has a single, undivided blade
Be able to explain what gene expression means (transcription and translation of genes)
· Gene expression: The appearance in a phenotype of a characteristic or effect attributed to a particular gene
· Transcription is the first step of gene expression, in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase
· Translation: The process by which messenger RNA directs the amino acid sequence of a growing polypeptide during protein synthesis.
Be able to explain that the differences in phenotype (structure and function) of cells with identical genomes is due to differences in gene expression
Different cells are activated
Be able to explain that cell differentiation is largely a result of expression
The normal process by which a less specialized cell develops or matures to possess a more distinct form and function.
Induced VS Repressed
If a lac repressor is active by itself it will bind to the operon and switch it off, an inducer inactivates the repressor.
multiple stages during transcription and translation
Be able to explain two ways in which modification of histone structure can affect transcription (acetylation and methylation)
· Acetylation: the process of introducing an acetyl group into a compound
· Methylation: a methyl group is added into the compoundHistone acetylation enhances transcription, which makes more gene product. DNA methylation makes it harder for DNA polymerase to bind to the DNA stand, which stops transcription and no gene product is made
Be able to explain how non-coding RNA such as microRNA can affect mRNA
The miRNA in the complex can bind to any target mRNA that contains at least 7 bases of complimentary sequence.
a unit made up of linked genes that is thought to regulate other genes responsible for protein synthesis.
a regulatory protein that binds to an operator and blocks transcription of the genes of an operon
Pertaining to the area where an enzyme can attach itself to a compound and react with it.
a promoter is a region of DNA that initiates transcription of a particular gene.
Part of the control element in which an transcriptional activator binds to speed up the rate of transcription
a protein that binds to specific DNA sequences, thereby controlling the flow (or transcription) of genetic information from DNA to mRNA.
a cellular RNA fragment that prevents the production of a particular protein by binding to and destroying the messenger RNA that would have produced the protein.
· Cytoplasmic determinants influence the course of early development
· Once an embryonic cell has undergone determination, it is irreversibly committed to its fate
· Therefore if a high number of cytoplasmic determinants are present the cell will go through early development
in a specific sequence
axis polarity, followed by organization into body regions, segmentation, and specifi characteristics (Drosophila).
highly conserved across animals (be able to explain what ‘highly conserved’ means)
Hox genes are a group of related genes that control the body plan of the embryo along the anterior-posterior axis. After the embryonic segments have formed, the Hox proteins determine the type of segment structures that will form on a given segment
relating to, caused by, or being a gene producing a usually major shift in the developmental fate of an organ or body part
the process by which cells become specialized in structure and function
the events that lead to the observable differentiation of a cell
any gene expressed in females whose mRNA transcript is found in the egg.
Know that development consists of fertilization, cleavage, gastrulation, and organogenesis be able to distinguish the basic processes occurring in each.
rapid cell divisions, hollow ball of cells is a blastula and a fluid filled cavity is a blastocoel, cell division without growth
Be able to explain the 2 mechanisms blocking polyspermy in sea urchins
· Acrosomal Reaction: Fast block to polyspermy: prevent additional sperm from fusing with the egg’s plasma membrane
· Cortical Reaction: Slow block to polyspermy: the fertilization envelope and other changes in the egg’s surface impede the entry of additional sperm nuclei, stimulates release of cortical enzymes out of the cell
If polyspermy were to occur, the resulting abnormal number of chromosomes in the embryo would be lethal
The vitelline membrane is a structure directly adjacent to the outer surface of the plasma membrane of an ovum. It is composed mostly of protein fibers, with protein receptors needed for sperm binding, which, in turn, are bound to sperm plasma membrane receptors.
The swelling of the vitelline layer away from the plasma membrane
protostome, planes of cell division are diagonal to the vertical axis of the embryo
the fate of each embryonic cell is determined early, protostome
a solid ball of cells resulting from division of a fertilized ovum, and from which a blastula is formed.
having a small amount of yolk, as certain eggs or ova, macro is having a lot of yolk
having cleavage planes that divide the egg into separate blastomeres.
Be able to distinguish cleavage pattern based on the type of egg
· Basically depends on amount of yolk
· Animals whose eggs have relatively little yolk are humans
· Yolk is more plemtiful in birds, reptiles, fish, and insects
· The more yolk the less cleavage furrows
· Ectoderm: outer layer, skin
· Mesoderm: middle layer, skeletal/muscle systems
· Endoderm: inner layer, epithelial lining of digestive tract
the embryonic gut - forms as a result of gastrulation
the opening of the central cavity of an embryo in the early stage of development
the rudimentary alimentary cavity of an embryo at the gastrula stage.
derived from the mesoderm the incomplete cleavage of a yolk-rich egg
having cleavage planes that divide the egg into separate blastomeres.
neurulation, the formation of the embryonic nervous system
Be able to describe and explain the example given (notochord stimulates the formation of the neural plate, neural tube stimulates neural crest cells)
· Notochord is the rod that extends along the dorsal side of the chordate embryo, signaling molecules induce the ectoderm above the notochord to become the neural plate.
· The neural plate rolls itself into the neural tube. The neural tube will become the brain and the head and the spinal chord along the rest of the body.
· Neural crest cells are the first set of band cells which develop along the borders where the neural tube pinches off from the ectoderm
Be able to explain the role of the grey crescent and the dorsal lip of the blastopore in organizing the frog embryo
The grey crescent forms on opposite side of sperm penetration When a group of cells on the dorsal side of the blastula begins to invaginate this forms a crease where the grey crescent formed, the part above the crease becomes the dorsal side of the blastopore, known as the dorsal lip.
Explain how morphogens work
Morphogens are chemical agents able to cause or determine morphogenesis.
groups of cells located in strips of mesoderm lateral to the notochord separate into blocks called somites
very important mechanism! The ability of one group of embryonic cells (an “organizer”) to influence the development of other cells via signal molecules (“inducers”) that alter gene expression
development of spatial organization in an embryo
1. Can be achieved by induction using morphogens and organizers
- e.g. bicoid factor in Drosophila (discussed earlier)
- e.g. vertebrate limb formation (chicken wing)
Pattern formation of limb digits facilitated by cell signals that direct PROGRAMMED CELL DEATH (PCD):
· If PCD fails in formation of the digits, digits remain joined by soft tissue.
· Compare, for example, the situation in the chick and duck hind limbs.
· If chick limb mesoderm is combined with duck ectoderm, PCD fails and the digits remain joined (Saunders, 1966).
This observation implicates the ectoderm in providing the signal to trigger PCD
Be able to explain how hormones act over the entire body
Hormone: a substance produced by a tissue or organ that travels and causes changes in target cells that have specific receptors
· Different tissues may respond differently to the same hormone (e.g., some may degenerate, others may develop or differentiate)
· Different tissues will respond to different threshold levels of a hormone
· *In this way, hormones can coordinate the timing of developmental events
· *Unlike a morphogen, hormones don’t rely on concentration gradients and provide no positional information.
Know that thyroxin controls the transformation of tadpoles into frogs
· Thyroid gland produces thyroxin (level is regulated by the pituitary gland)
· Thryroxin signal molecules target cells with the appropriate receptors; receptor binding will activate some genes and repress other genes
· Different tissues will respond at different times as thyroxin levels increase
· For example: limbs develop before tail degenerates; lungs develop before gills degenerate
in birds, some fishes, and some insects, the sex chromosomes present in the egg determine the sex of the offspring. The sex chromosomes are designated Z & W. females are ZW and males are ZZ.
there are no sex chromosomes in most species of bees and ants. Females develop from fertilized eggs and thus are diploid. Males develop from unfertilized eggs and are haploid they have no fathers.
only one X chromosome
Basically indistinguishable from XX females
· Some menstrual irregularities, taller than average,
· May have mild learning disabilities.
· Minor differences from XY males
· More rapid growth, taller than average, likely have
· Mild learning disabilities.
Haplodiploidy is a sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid.
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