When two organisms are needed to produce an offspring. One provides the sperm and the other provides the egg. After the egg is fertilized it is called a zygote.
A cell's endowment of DNA. Prokaryotic cells may be made with as little as one strand of DNA while eukaryotic genomes usually consist of multiple DNA molecules.
The location where all of a cell's DNA is packed into before reproduction
All body cells except the reproductive ones. Human somatic cells contain 46 chromosomes
Reproductive cells (sperm and eggs). They have 23 chromosomes each in humans.
The material that make up chromosomes. They're a complex of DNA and associated protein molecules.
When a chromosome is duplicated, two sister chromatids are produced.
In its condensed form, the duplicated chromosome has a narrow "waist" at the centromere, where the two chromatids are most closesly attached.
The division of the nucleus (see study guide for more detailed account.
The division of the cytoplasm
The process by which humans produce gametes. In meiosis, non-identical daughter cells are produced which only have one set of chromosomes-half as many as the parent cell. Occurs is gonads
Much larger process than mitosis in which cell growth occurs and the cell copies its chromosomes in preperation for cell division
G1 Phase (Interphase)
The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins
S Phase (interphase)
The Synthesis phase of the cell cycle; the portion of interphase where DNA is replicated
G2 Phase (interphase)
The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.
G0 Phase (interphase)
A nondividing state occupied by cells that have left the cell cycle
Chromosomes condense. The nucleoli disappear. Each duplicated chromosome appears as two identical sister chromatids joint at the centromere The miotic spundble begins to form.
Longest stage of mitosis, lasting up to 20 mins. Centromeres move to opposite ends of the cell. Chromosomes convene on the metaphase plate, a plane between the two poles.
Shortest stage of mitosis. Begins when the coheasion proteins are cleaved, which allows the two sister chromatids to suddenly part. By the end of this phase, the two ends of the cell have an equivalent set of chromosomes.
Two daugther nuclei form in the cell. Nucleoli repapear. With this phase, Mitosis is complete.
Division of ctoplasm that occurs concurrently with Mitosis.
A cell containg two sets of 23 chromosomes (ech inherited from one parent). So, 46 chromosomes total.
Sexual or reproductive cells. Each only have 23 chromosoms.
Consists of fibers made of microtubules and associated proteins
Site of spindle microtubule assembly.
Structure of protein associated with specific sections of chromosomal DNA at the centomere. A chromosome's two kinetochores face in opposite directions
In animal cells, cytokinesis occurs through cleavage (characterized by the pinching of the plasma membrane) (2) The succession of rapid cell divisions without significant growth during early embryotic development that converts zygotes to balls of cells.
The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.
Asexual Reproduction in eukaryotes. Division in half.
Origin of replication
Site where the replication of a DNA molecule begins. COnsists of a specific sequence of nucleotides.
Cell cycle checkpoints
If conditions are not correct at any of these checkpoints, cell should not proceed through. (1) Fix Problem: can move past check point (2) Can't fix: cell suicide pathway (3) If not fixed and cell continues, cancer occurs.
Unregulated cell division, cells can pass hrough checkpoints even if damaged or wrong
Checks cell size, DNA integrity: DNA is intact and in good shape. Most important checkpojnt in mammal cells. Also called the restriction point.
Checks cell size, completetion of replication and DNA integrity
Metaphase. Checks that all chromosomes attached to kinetochore tubule
Protein released by a cell that stimulates other cells to divide
Receptor is the cell to receive signal. SIgnal molecule binds to receptor and receptor is activated (shape change or chemical reaction modify)
Converting external signal to internal message (relay molecules in signal transduction pathway)
Response to transduction
Activation of cellular response. Turn on cell control genes: activation of cell division
Little signal = BIG response
Process that converts a normal cell into a cancer cell
When abnormal cells stay at the original site
Travels to other parts of the body. Impairs the function of one or more organs.
The spread of cancer cells to locations distant from their original site.
Genes that if damaged, will lead to cancer?
growth factors, their receptors, intracellular molecules of signaling pathways
genes that encode signals, receptors, signaling molecules, control proteins, etc. If these genes are mutated they turn into oncogenes and cause cancer
Cancer causing genes. Arrise from a genetic change that leads to an increase either in the amount of the proto-oncogenes protein product or in the intrinsic activity of each protein molecule.
Three types of genetic changes that convert p-oncogenes into oncogenes
movement of DNA within the genome, amplification of a p-oncogene, and point mutations in a control element or in the p-oncogene itself
mistakes in DNA replication, exposure to mutagen (UV light, tobacco), virus inserting DNA into gene. Abnormal protein can be hyperactive, tell cell to be "ON" all the time and continuously divide.
(Her2 example and herceptin). Normal protein, but way too much: over stimulate cell
Proto-oncogene, membrane receptor, when a signal molecule binds to Her2, genes are turned on : Stimulate cell division and inhibit cells from dying
proteins that recognize and bind specific molecules. Antibody made that can bind to Her2 receptors (Herceptin): blocks off binding site for receptors
Proteins that inhibit cell division; shut down cell division if conditions are not favorable. Some detect and/or repair DNA damage (if mutated: override checkpoints). Some make sure cells are anchored (if mutates: cells invade other parts of the body). Normal and need to have them.
BRCA2 helps repair damaged DNA at G2. If mutated: damaged DNA but still go through mitosis; check point doesn't matter: increased risk for breast and ovarian cancer
Helps cells decide wether to repair damaged DNA or commit cellular suicide. If damaged, can cause cervical cancer. A cell w/ damaged p53 doesn't make a cell decision, just divides and tumor cells proliferate
HPV and cervical cancer
DNA integrates into host genome, HPV proteins made, E6 and E7 proteins destroy p53.
Tumor supressors can be silenced by abberant methylation: no tumor supressor genes made: epigenetic phenomenon
Ends of linear chromosomes, shorten with each cell division, after ~40 divisions, cell dies. Idea is that cells should die before they have had time to accumulate loads of damage
Enzyme that permits the entire telomere to be replicated, so chromosomes don't shorten. Almost all cancer cells have telomerase on. Telomerase activity detected in almost all tumors -> cell immortality. Mice enginerred w/ telomerase in all cells got cancer.
Telomerase inhibitors. Single stranded nucleic acid complimentary to mRNA molecules made by cell.
Multi-step model of cancer development
(Step 1-2) Benign growth: localized mass of cells; (Step 3) Malignant growth: tumor cells invade neighboring tissue; (Step 4) Metastasis: cancer cells spread through lymph and blood vessels to rest of the body
Density dependant inhibition
Phenomenon in which overcrowded cells stop dividing. Prevent cells from mving forward in the growth process.
injection of cehmicals into blood stream to kill dividing cells. Some prevent mitosis. Taxol prevents MTs from shortening. Some stop DNA replication. Nonselective: will affect ANY rapidly dividing cells
The process in which haploid gametes (sperms or eggs) are formed
Chromosomes replicate in what phase of cell cycle?
The S cycle
Chromosomes condense, SYNAPSOS: homologous chromosomes pair up. Paired state = bivalent. Crossing over occurs. Nuclear envelope breaks down, spindle formation like it mitosis (but in mitosis they do not pair up and there is no crossing over
exchange of genetic material between chromosomes (where cross occurs, chromosome can break)
Homologous chromosomes line up on metaphase plate. Arrangement of parental and maternal chromosomes on metaphase plate is random: random alignment or independant assortment. Still needs to be in homologous pairs
Homologous chromosomes moved to opposite sides of cell (sister chromatids still attached at centromere). Kinetochore MTs shorten and polar MTs lengthen as in mitosis
Each half of cell has complete haploid set of replicated chromosomes -> ready to go to meiosis II. In animal celss, cleavage furrow forms in mitosis. NO DNA REPLICATION.
If chromosomes decondensed in telophase I, they recondense here
Chromosomes line up on metaphase plate (singly, as in mitosis)
4 haploid cells, different from parent, different from each other.
Either of 2 copies of a duplicated chromosome attached to each other by proteins at the centromere. While joined, two sister chromatids make up one chromosome, but they eventually split in meiosis or mitosis II
Two chromosomes of the same length, centromere position, and staining pattern
Genetic variation in humans is due to?
random alignment on metaphase I plate. Alleles. During meiosis I, tetrads can link up two different ways before homologs seperate
How many possible combinations of maternal/parental homologs can you produce?
In general, diploid organism can produce 2n combination. n= haploid chromosome number. n= 23, so 223 = 8.4 million different gametes
Fertilization and genetic variaton
8.4m x 8.4 mil = 70 trillion diploid
members of a pair of homologous chromosomes or 2 pair of sister chromatids do not seperate properly. n + 1 = extra gamete, n - 1 = missing gamete
Alteration on chromosome number
Occurs when fertilization involving a gamete that has no copy of a particular chromosome. Leads to missing chromosome in zygote. Can cause Turner's Disease
Absence of an entire sex chromosome. Instead of being a normal XX female, there is only one X chromosome, and this leads to things like non-working ovaries, shortness, physical abnormalities.
Has one extra sex chromosome. Causes Down's syndrome.
Caused by the rpesence of an extra sex chromosome and causes strange facial features, shortness, heart defects, and mental retardation. Also called trisomy 21.
Occurs when someone has three copies of genetic material from chromosome 13. Causes cleft pallate, clenched hands, extra fingers, seizures, undescended testicles, etc
Person has three copies of chromosome 18. Symptoms are clenched hands, mental deficiency, unusually shaped chest
Males, instead of being XY, are XXY. Causes small testicles and reduced fertility
Pre natal tests can be given to determine if a baby has a specific genetic defect
Maternal Age and Down's
The older the mother is, there is a MUCH larger chance of a child having Down's syndrome
Chorionic vilus sampling
8th-10th week of pregnancy. Placental sample is extracted and tested
14th-16th week. Extract amniotic fluid; culture cells for weeks; karyotype.
non-homologous chromosomes exchange fragments. This is the 3rd way in which a p-oncogene can become an oncogene. The oncogene encodes abnormal "fusion" protein. Fusion protein constantly activates a number of cell activites that normally are turned on when the cell is stimulated by growth factors.
The parental generation
The offspring of the P generation
The offspring of the F1 generation
alteranative version of the gene; both alleles can be the same or alleles can be different. Each organism has two alleles, one from each parent
A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA
True breeding strains
Fllowers, for example. Each generation must give rise to the same purple flowers for it to be a true breeding strain
A specific spot along the length of a chromosome where a given gene is located.
Will always override a recessive gene at a given locus
Will always be covered up by the dominant allele
Organisms that are heterozygous for one character
2 different alleles
2 identical alleles
physical traits of an organism determined by genotype
The genetic make up, or set of alleles of an organism
Law of Independant Assortment
Each pair of alleles segregates independantly of other pairs of alleles during gamete formation.
Means that two dominant genes and their phenotypes will both be distinctly seen in their offspring. For example, a Red and White Flower produce a red flower with white spots
The two alleles blend together. For example, a red and a white flower produce a pink flower
Breeding an organism of unknown genotype with a homozygous recessive individual to determine the unknown genotype. The ratio of the phenotypes in the offspring reveals the unknown genotype
A diagram of a family tree showing the occurence of heritable characters in parents and offspring over multiple generations
Addition of molecules, like methyl groups (-CH3) to the DNA backbone
Change appearance and structure of DNA, which then changes gene expression
loosely packed (expressed)
Tightly packed (not expressed)
A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome. In Barr bodies, most genes are not expressed at all
one X chromosome almost completely inactivated in embryotic development.
any process that alters gene activity without changing the DNA sequence, leads to modifications that can be transmitted to daugther cells (gene turned on so protein can be made)
We use chemical energy to carry out cell activites; electrons in chemical bonds of food have lots of chemical energy -> harness energy from bonds - > ATP
Glucose + O2 + ADP + Pi --> CO2 + H20 + ATP
See in class review diagram for more info
ATP = ADP + P
Protein is phosphorylated
Where does cellular respiration occur?
Outer mitochondrial membrane, Inner mitochondrial membrane, Matrix and innermembrane space. In the mitochondria
Steps of Cellular Respiration
Glycolysis, The citric acid cycle, Oxidative Phosphorylation: electron transport chemiosmosis
Sugars break down. Occurs in cystol.
Glucose > 2 pyruvate > into mitochondria.
Net gain of 2 ATPs (2 invested 4 gained)
2 NADH Also made
2 NADH, 2ATP, 2 pyruvates
2 pyruvates = NADH (x2), 2Acetyla CoA, and CO2 (x2)
3NADH (x2), FADH2 (x2), 2CO2 (x2), and ATP (x2)
So, what do we have at this point in respiration (After Glycolysis, Pyruvate Processing, and Krebs Cycle) ?
4 ATPs have been made while ripping apart the glucose
What happens when glucose breaks down?
Bonds broken/new bonds form
Electrons get shuffled (we are interested in what happened to those electrons)
Substrate Level Phosphorylation
ATPs made by glycolysis, pyruvate processing and Krebs cycle formed by substrate level phosphorylation. Enzyme grabs P from a molecule (a substrate) and transfers it to ADP
But, 4 ATPs is NOT a lot of energy harnessed from those chemical bonds, and its NOT enough to run a multicellular organism
NADH and FADH2
Electron storers/shuttlers. They give these electrons to the electron transport chain (ETC).
Electron Transport Chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP. Movement of electrons provides energy for H+ pumps
O2 and the electron transport chain
Is the final acceptor of electrons in the electron transport chain
Folds in the inner mitochondrial membrane that hold the electron transport chain.
Produces 32-34 ATP. Formation of ATP through combination of proton pumping by ETC and action of ATP synthase: makes LOTS of ATP
H+ flows through ATP synthase complex through facilitated diffusion. Catalyzes formation of ATP, converts energy in H+ gradient > leads to ATP energy.
Movement of x across cell membrane. Uses ATP. Moves up concentration gradient
Passage of molecules or ions across a biological membrane with the assistance of specific transmembrane transport proteins
Pepsin remains in inactive form, pepsinogen. It seretes pepsin only when food is present so that way it doesnt eat away stomach lining.
Mucus cells secrete mucus that is a protective layer on top of the stomach layer
Stomach epitheleal cells > rapid mitosis
How are carbs digested?
trypsin and other protease from the pancreas
Made in liver, stored in gall bladder, emulsifies fat
Longer SI > more time for digestion, more surface area for absorbtion. Herbivores have evolved to have long SI and cecum.
anaerobic chamber that contains cellulose digesting molecules.
How are nucleic acids digested?
Nucleases made by pancreas > nucleotides
Absoprtion (small intestine)
Uptake of specific nutrient molecules/ions
Small intestine has large surface area for absorption
Fats form chylomicron > lacteals
All other nutirents > capillaries > rest of body
Nutrients > Blood Stream > liver > rest of body
Fatty Acids combine w/ cholestorol and proteins to form chylyomicron > lacteal
Functions of the large intestine
Reclaiming water, elimination of solid wastes, mutualistic relationship with bacteria
Tight junctions in Intestines
connect cells lining intestines- you want food to go through cells, not between them. Holds cells together, inhibits movement of dissolved material thru spaces in the cell
Hormone that regulates food intake. Produced by Adipose fat cells, most obese people have mutation in leptin receptor
chemical messenger released into blood stream that acts on distant target cells. Secretion of digestive enzymes controlled by hormones
After eatign, stomach and SI release hormones that supress appetite
Leptin release and fat cell size?
Smaller fat cells secrete less leptin, so increase food intake, decrease metabolic rate and vice versa
maintenance of constant internal conditions (normal fat cells maintained)
a change in variable triggers mechanisms that reverse that change- tells big fat cells to get smaller and small fat cells to get bigger
The largest section of the large intestine; functions in water absorbtion and formation of feces
A small, finger like extension of the cecum, contains white blood cells that contribute to immunity
Channel that conducts food, through perastalsis, from the pharynx to the stomach
An organ that stores bile and releases it when needed into the small intestine
The largest internal organ in the body. It performs diverse functions, like producing bile, preparing nitrogenous waste for disposal, and detoxifying poisonous chemicals in the body
Gland with dual functions: Nonendocrine portion functions in digestion, secreting enzymes and an alkaline solution into the small intestine. The ductless portion functions in homeostasis, secreting the hormones insulin and glucagin into the blood
In throat- food and air pass across.
Portion of large intes. where feces are stored
Gas exchange occurs?
Between animals' mitochondria and external environment.
Involves ventilation, circulation, and cell respiration
movement of air or water across an exchange surface
dissolved gasses transported through body via circulatory system
Common Features of respiratory surfaces
Thin (for diffusion), large surface area, Moist (gasses must be dissolved in water), composed of living cells
Spontaneous movement down a concentration gradient.
fluid filling the spaces between the cells of an animal
adapted for gas exchange in acquatic environment
Structure: out growth of body surface
Gill arch: holds many different gill filaments
How are gills ventilated
opening and closing mouth and operculum > pumps water and creates a pressure to ventilate gills
Swimming with mouth open, more flow of water, more oxygen
Gills and Gas Exchange
Gas exchange is hard in water; it contains much less oxygen than air and its harder to move across respiratory surface w/o air
Gas Exchange in fish
Flow of water over fish gills is unidirectional
Flows only 1 way
Gill arches hold filaments, each gill filament is richly supplied with blood vessels...water is always flowing over filaments in 1 direction and blood flows in OPPOSITE direction
The flow of blood in the opposite direction to flow of water-very efficient mechanism to extract oxygen out of water.
*O2 in respiration surface always higher then )2 in blood because of concurrent flow
The amount of water a fish inhales and exhales in concurrent exchange
Structure of Tracheal System?
Extensive system of tubules throughout the body, open and spiracles, which can close of if needed to minimize water loss
Do fish have circulatory systems?
No because gas exchange via tubules in contact with all cells in body
Ventilation: Small v Large insects
Small use diffusion, large use muscle contraction
Lungs Structure (5 parts)
trachea, lungs, bronchi, bronchioles, alveoli
Gas Exchange at alveolor surface?
alveolor of lungs is ourrespiratory surface: HUGE surface area
Gases move by simple diffusion into bloodstream; move dwon pressure gradients (high to low pressure)
Ventilation in humans
Negative Pressure breathing- we pull air into our lungs. Breath in, muscles contract, rib cage expands, diaphragm contrasts, volume of chest cavity increases so the pressure decreases, so air will go into lungs. When you breath out, diaphragm relaxes and air comes out
Air flow is tidal or non tidal?
Tidal: flows in and out through same pathway
Dont have gas exchange along entire respiratory surface Tidal is least efficient.
air left in aveoli after exhalation (oxygen depleted dead air)
Ventilation in birds?
Uses crosscurrent exchange. Respiratory surface is parabronchi. Air sacs push aire through lungs
Is air flow in birds one or two way?
One way air flow through parabronchi
Airflow v. Blood Flow in birds
AIr flow is crosscurrent with blood flow.
Air flows in one direction
Gas exchange along ENTIRE respiratory surface
Efficiency: Crosscurrent v. Countercurrent flow
Counter current is more efficient than cross current flow
Fine branch of the bronchi that transports air to alveoli
A dead end, multilobed air sacs where gas exchange occurs in the mamallian lung
A microscopic blood vessel that penetrates tissue and consists of singlle layer of cells that allows exchange between blood and interstitial fluid. Essential in gas exchange.
What is blood composed of (2 parts)?
Plasma and Cells
Function of Circulatory System?
deliver nutrients, deliver gasses, remove waste, circulate hormones, immune function