BIOLOGY EXAM!!!
Digestive system parts
-Teeth
-Epiglottis
-Liver
-Gall bladder
-Common bile duct
-Ascending colon
-Appendix
-Salivary gland
-Tongue
-Esophagus
-Stomach
-Duodenum
-Pancreas
-Small intestine
-Rectum
Macromolecules and enzymes
Molecules are large and must be broken down in smaller soluble components before they can be absorbed.
Carbohydrates
Carbohydrates are macromolecules, very large and made up of smaller molecules that are linked together. Made of carbon hydrogen and oxygen and are the main source of energy for humans.
Glucose
Glucose, a monosaccharide, is used during cellular respiration to provide energy to the cell
Glucose is a type of carbohydrate?
Provides materials to build cell membrane
Disaccharides
Made up of 2 simple sugars joined together
Ex lactose (sugar in milk) sucrose (table sugar)
Polysaccharide
Simple sugars joined together (there are many different types)
Starches and cellulose are examples that are made and stored in plants
Cellulose has a straight rigid structure
Glycogen is a polysaccharide that is made and stored in animals and is highly branched
Proteins
-made up of long chains of amino acids joined together by a peptide bond
-functions provide structure and support, body tissues, muscles
-Some proteins are enzymes, hormones, antibodies and can be a source of energy
Lipids
Lipids
-Are energy storage molecules, are the main components of cell membranes (phospholipid), serve a insulation, help in absorption of vitamins
-insoluble in water
-make up triglycerides and fatty acid chains
-Ex) butter, lard, oil
Nucleic acids
-Are DNA (desoxyribonucléique acid) and RNA
Direct growth and development using a chemical code
-ATP - adenosine triphosphate is a molecule that stored energy
Vitamins
Are compounds needed in small amounts to regulate cell functions and growth
Minerals
Help to carry out metabolic processes and to build or repair tissues
-calcium and phosphorus for formation of bones, sodium needed in muscle contraction and nerve impulse transmission
-Iron is a mineral and an important component of red blood cells
-Other cool minerals: Fluorine, Zinc, Copper, Magnesium
Enzymes
Are proteins that act as a catalyst increase the rate of reactions without being used up by reactions
The chemical breakdown of the macromolecules of carbohydrates, lipids, proteins is called hydrolysis
During hydrolysis a water molecule is added to the macromolecule and it breaks it into smaller molecules with the help of enzymes
Hydrolysis
Hydrolysis is the breakdown of larger molecules using water
Enzymes are needed to make hydrolysis happen fast enough in the body
Digestive Enzymes
The breakdown of food happens slowly at body temperature. Enzymes lower the activation energy allowing this process to take place more quickly. Like all enzymes digestive enzymes work best under very specific conditions (correct ph, correct temperature, necessary vitamins, ions or coenzymes are present)
Production of digestive enzymes
They are produced in the salivary glands, stomach, small intestines, and pancreas
Enzymes may be produced in simple severe cells or in glands
Many enzymes produced in the pancreas act in the small intestine
Absorption:
refers to the transfer of molecules from food in the digestive system to to the bloodstream
Assimilation:
refers to the conversion of the nutrients into parts of the organism
Accessory Organs
Liver
Gall
bladder
Pancreas
Stomach
-temporary storage holder
-acidic environment breaking down proteins plus kills any dangerous pathogens
Liver
-Produces bile to break down fats
-Detoxifies
-conserves glycogen so it can break it down in our blood stream during exercise for energy
Pancreas
-regulates blood sugar, insulin
-breaks down carbohydrates
small intestine
-Digestion and absorption
villi and microvill do absorption
enzymes and bile do digestion
Lumen?
?
Large intestine
absorbs liquids
DNA structure
genetic information concerning protein synthesis
Huge polymer made of monomers called nucleotides
Each nucleotide contains a 5-carbon sugar, a phosphate group, and a nitrogenous base
Nucleobase/nitrogenous bases:
Cytosine and thymine are pyrimidines (containing a single ring)
Adenine and guanine are purines (containing a double ring)
Thymine binds to adenine, cytosine binds to guanine—both through hydrogen bonding
Phosphodiester linkage (covalent bonding) between sugar and phosphate
Glycosyl bond between sugar and nitrogenous base
DNA is wound around proteins called histones
Protein synthesis
DNA (transcription) → RNA (translation) → protein
Transcription → copying of information from genes on DNA to messenger RNA
Translation → production of proteins composed of amino acids at ribosome with messenger RNA controlling the sequence of amino acids
In the nucleus DNA is transcribed into RNA. the RNA carries the “message” out the nucleus and into the ribosome into cytoplasm, where tRNA is able to translate the message to make a protein (occurs on ribosomes)
mutations
Point mutations are caused by the substitution of a single nucleotide for another nucleotide, like adenine being put in place of thymine. This can be harmless or lead to the production of a malfunctioning protein.
Insertion is when an extra nucleotide is placed in the DNA sequence. If the number of nucleotides inserted is a multiple of three, frameshifting has not occurred. If the number of inserted nucleotides is not a multiple of three, frameshifting has occurred. This is because codons, the units of the genetic code, consist of nucleotide triplets, and so insertion of a number that is not a multiple of three will disrupt the reading frame of a gene sequence.
☆ Frameshifting occurs when the reading frame of a gene sequence is disrupted ☆
Deletion involves the elimination of a base pair or group of base pairs from a sequence of DNA. The same concept of frameshifting applies to deletion.
Translocation occurs when a fragment of one chromosome breaks off and attaches to another chromosome. This disrupted gene is transcribed, resulting in a fusion protein with an altered function.
Nondisjunction
Nondisjunction occurs when the separation process of chromosomes in cell division fails, leading to the same daughter cell receiving both chromosomes.
Independent assortment
Independent assortment, which states that genes are inherited independently of one another, and crossing over, the exchange of genetic material between non-sister chromatids of homologous chromosomes during meiosis, ensure genetic recombination, otherwise known as genetic variation.
Mitosis
Type of cell division in which a daughter cell receives the same number of chromosomes as the parent cell
Interphase, prophase, anaphase, telophase, cytokinesis
Meiosis
Process by which gametes are formed. Each gamete will contain half the chromosomes of the parent.
A zygote is the diploid cell resulting from the fusion of two haploid gametes
In Meiosis I, 2n → n (Start with 46 chromosomes. End with 23. Number of nuclei is doubled).
In Meiosis II, n → n (Number of nuclei doubled since meiosis I and quadrupled since before the process. Still a haploid, no further reduction in chromosomes).
Genetic recombination, or crossing over, occurs at a point called the chiasmata when homologous chromosomes intertwine during Prophase I
In Metaphase I and Metaphase II, random orientation of chromosomes takes place.
Punnett squares
The phenotype is defined as the physical traits and characteristics of a cell or organism
The genotype consists of the alleles an organism contains for a particular trait
Test cross
A test cross is used to determine of a particular organism is homozygous dominant or heterozygous.An individual of unknown genotype is crossed with a homozygous recessive individual
If the offspring show recessive traits, the parent with the unknown genotype must be heterozygous
If all offspring show the dominant trait, the parent with the unknown genotype must be homozygous dominant
Incomplete dominance
Incomplete dominance occurs when alleles are of equal strength
The two traits are thus blended
The heterozygous condition produces a phenotype which is an intermediate between the two homozygous parents
For instance, if there is incomplete dominance of a red flower colour over white, the heterozygous plant would be pink.
All dominant traits, all caps (e.g. RR, RW, WW)
Codominance
Codominance occurs when the expression of one allele does not mask the expression of the other.
For instance, in shorthorn cattle, a red bull crossed with a white cow produces a roan calf, which has spotted white and red hair.
Notation is funky, looks like: CWCW for white, CRCR for red, and CRCW for roan
Blood
Codominance in blood
Blood types A, B, AB, O
Allele for type A blood is IA
Allele for type B blood is IB
Allele for type O blood is i
IA and IB are dominant to i, and IA and IB are codominant to each other
Type A
Type B
Type O
Type AB
IAIA or IAi
IBIB or IBi
ii
IAIB
Blood types are based on antigens A and B
Sex-linked inheritance
Females XX, males XY
X chromosomes carry genes for many traits. Y chromosomes do not carry genes for other traits.
For any genes carried on the X chromosome, the phenotype of the male depends on the allele carried by only one X chromosome. Meanwhile, the phenotype of the female depends on the alleles carried by both X chromosomes.
Notation would look like: XHXh X XHY
Pedigree notation and analysis
In pedigree notation, circles represent females and squares males. A darkened square or circle represents an individual affected by the trait.
Pedigree notation traits
Autosomal recessive traits
Autosomal dominant traits
X-linked dominant traits
X-linked recessive traits
Gene linkage
A group of genes inherited together because they are found on the same chromosome
Recombinant chromosomes are a result of crossing-over. They are chromosomes with a genotype unique from those of the parents.
9:3:3:1 ratio for offspring of two parents heterozygous for both traits. 9 will have both dominant traits, 3 will have one dominant trait and one recessive trait, 3 will have the other dominant trait and the other recessive trait, 1 will have both recessive traits.
Example problem: In humans, interacting genes control hair colour. Brown hair (B) is dominant to blond (b). Dominant (M) allows melanin synthesis, recessive (m) prevents melanin synthesis. Homozygous recessives (mm) will be albino. Calculate the expected phenotype ratios of children of BbMm X bbmm:
X-linked recessive traits
all sons of an affected mother are affected; affected fathers never transmit the trait to their son; unaffected parents may have affected offspring; generally, more males than females possess the trait
X-linked dominant traits
each generation usually has an affected individual; all daughters of affected males are affected; both sons and daughters of an affected heterozygous female may be affected; generally, twice as many females have the trait than males
Autosomal dominant traits
if a child has the trait, at least one parent must also have the trait; if neither of the parents have the trait, the offspring will not exhibit it either; if both parents do have the trait, but the offspring does not, then the child will be homozygous recessive and the parents will be heterozygous or carriers; the trait does not skip generations.
Autosomal recessive traits
males and females are equally represented for having the trait; if both parents are affected, the offspring should be also; if both parents are unaffected, but the offspring has the trait, then the parents must be heterozygous; the trait can skip generations
Chi-square
First, identify the hypotheses (null versus alternative)
Construct a table of frequencies (observed versus expected)
Apply the chi-squared formula → x2 = (o-e)2e, where o represents the observed results and e represents the expected results
Determine the degree of freedom (df), which is the number of categories minus one
Identify the probability value (should be <0.05)
If the p-value is less than 0.05, we’ll accept the null hypothesis. If it is greater than 0.05, we’ll reject the null hypothesis.
Respiration
Allows for ventilation, gas exchange (internal and external), and cellular respiration
Requirements for respiration include a large surface area and a moist environment
Ventilation
Ventilation
Inhalation and exhalation
When you inhale, the diaphragm contracts, shortens, and moves down. External intercostal muscles contract. Internal intercostal muscles relax. Ribs move up and outward. Air pressure in the lungs decreases, and air rushes in to equalize the difference in air pressure. Negative pressure.
When you exhale, the diaphragm relaxes, curves, and moves up. External intercostal muscles relax. Internal intercostal muscles contract. Ribs move down and inward. Air pressure in the lungs increases, and air rushes out to equalize the difference in pressure. Positive pressure.
Internal and external intercostal muscles are antagonistic muscles
Bronchi and bronchioles
Bronchi are supported by ridges of cartilages
Bronchioles are lined with smooth muscle and can contrast to decrease their diameter
Defence mechanisms respiratory system
Mucus traps small particles and debris that invade the lungs, and the wave-like motions of cilia carry the unwanted matter up the trachea to be coughed up.
Alveolar macrophages clear the alveoli of pathogens
Alveoli
Located at end of bronchioles
Where gas exchange takes place
Large surface-area-to-volume ratio, allowing for a high rate of gas exchange
Single-celled walls, allowing gas exchange to occur more rapidly
Concentration gradients facilitate diffusion between alveoli and capillaries
Coated in a layer of fluid that allows for the dissolution of gases. This promotes rapid diffusion.
Alveolar cells
Alveolar cells
Type I pneumocytes → extremely thin alveolar cells designed for diffusion and gas exchange. Line alveolar surface. Flat and thin.
Type II pneumocytes → Secrete the fluid that coats the inner surface of the alveoli. This creates a moist surface that prevents the sides of the alveoli from sticking to the other. Cubic in shape.
Gas exchange in respiratory system
Diffusion
Blood entering the alveoli has a low concentration of oxygen gas compared to the alveoli. Oxygen gas diffuses into the blood by means of the single-celled walls of the alveoli and capillaries. Carbon dioxide also diffuses out of the blood into the air in the lungs due to concentration gradients, and is breathed out.
Transport of gases
Oxygen displays cooperative binding to haemoglobin, meaning the more oxygen that is bound to haemoglobin, the higher the haemoglobin’s affinity for oxygen.
Although carbon dioxide in the body is primarily dissolved in plasma, it is also transported by binding to haemoglobin. Carbon dioxide on its own does not compete with oxygen binding, but it affects the release of oxygen. When carbon dioxide from respiring tissue enters a erythrocyte through diffusion, it is converted into hydrogen ions and bicarbonate. The presence of hydrogen ions makes the erythrocyte’s environment less basic. Since haemoglobin’s affinity for oxygen decreases in acidic environments, it releases its bound oxygen into blood plasma so that oxygen can diffuse into respiring cells.