Lab Exam 1 Flashcards
Calculate total magnification
4 x 10 = 40
10 x 10 = 100
40 x 10 = 400
Describe how to create a wet mount
Take a glass slide
Add a drop of water to a slide and place the specimen in the water (or you may have to place the specimen first and then add the drop of water)
Place the edge of the coverslip on the slide so it touches the edge of the water
Slowly lower the coverslip to prevent the formation and trapping of air bubbles
Remove excess water from the slide using lens paper
Biological domains
LOOK AT PAGES 13 and 14 for pictures!
Archaea
Bacteria (Cocci, Bacilli, Spirilla)
Eukarya
Eukaryotic kingdoms and an example of an organism in each
LOOK AT PAGES 13-15 for pictures!
Protista - Paramecium, Amoeba, Euglena (active; single-celled; have organelles that can be observed; complex; euglena are easiest to observe; green pigments)
Fungi - Yeast and molds, Penicillium conidia (single-celled and multicelled; grow hyphae, which are long, branching filaments (thread-like) structures)
Plantae - Azolla (multicellular; photosynthetic pigments make easy to see; should not move around; can be seen with naked eye)
Animalae - Rotifers (aka wheel animals), daphnia (aka water fleas); (multi-cellular; complex structure)
Hypothesis
- Reflects a tentative answer to a question
- It restates a question with a possible explanation for the observation
Control Group
Group that is not exposed to the (independent) variable
Experimental Group
Group that is exposed to the (independent) variable
Dependent Variable vs. Independent Variable
DV: the outcome you measure (that is meant to be influenced by the IV)
IV: the characteristic you control and manipulate between groups
Differentiate the steps of the scientific method and the different approaches demonstrated in lab
Observe → Hypothesize → Test → Interpret
-Used to develop scientific knowledge
Biomolecules
Macromolecules (large molecules) found in living systems that contain five or more carbon atoms in either ting or chain formation
-We get MACROmolecules form the food we eat
4 key biomolecules essential to life?
Carbohydrates
Lipids
Proteins
Nucleic Acids
Organic Compounds
Substances that contain carbon, hydrogen, and oxygen (the 4 key biomolecules are organic compounds)
Indicators
Special chemicals that change in some way in the presence of a specific organic substance
Triglyceride
- Type of lipid
- Consist of a glycerol molecule combined with three fatty acids
Hydrophilic
- Water loving
- Polar molecules that are soluble in water
- Polar molecules tend to have slight differences in electrical charge associated with different parts of their molecular structure; this polarity is caused by unequal sharing of electrons associated with the internal bonds that hold the molecule together
Hydrophobic
- Water fearing
- Polar molecules that are not soluble in water
Recognize tests and indicators that detect the presence of carbohydrates, lipids, and proteins
- Sudan III
- The Biuret Test
- Benedict’s Reagent
- Iodine
The Biuret Test
Detects proteins and peptides
- Positive = Reactant changed from blue to violet color (pinkish-purple) because of amine groups in amino acids reacting with copper ions
- Negative = Blue color
Benedict’s Reagent
Detects reducing sugars (carbohydrates)
- Positive = Green (low concentration); Yellow, orange, or red-orange (high concentration)
- Negative = Maintains blue color
Iodine
Detects for starches (carbohydrates)
- Positive = Changes from maroon (brownish) to dark blue-black color
- Negative = Maintains brownish color
Sudan III
Detects Lipids
- Positive = orange-colored spot on the filter paper
- Negative = indicated by a spot lacking color OR one with red particles
- It’s hydrophobic
- Polar molecules won’t take up this dye
Amino Acid
- Basic unit of protein
- Bond between amino acids is called a peptide bonds
Monosaccharide
- One-sugar or singular sugar
- Basic building blocks for carbohydrates (simple sugars)
- Ex: glucose and fructose
Polysaccharide
- Sugars containing several to many monosaccharides linked together (many-sugars)
- Ex: starch
Describe the controls used in the biochemical tests
- The control for all the tests was distilled water (dH2O) because it does not contain any macromolecules
- If control gives you a positive result, test is invalid (because solutions likely to be contaminated)
Recognize the typical structures in human cells
- Structure of a typical cell is divided into three major parts:
1) Plasma membrane (cell membrane), which envelops (or encloses) the rest of the cell
2) Cytoplasm, which is comprised of a liquid medium known as cytosol containing the functional subunits called organelles
3) A membrane-bound structure that contains DNA, the nucleus - Each cell is a membrane-enclosed sac containing smaller subunits that perform cellular function
Plasma Membrane
- Structure: Mixture of water, salts, and organic molecules that form a thick fluid (cytosol) and organized structures (organelles)
- Location: Interior of cell
- Primary Function: Region of cellular metabolism and other activities that maintain the cell
Cytosol
- Structure: Thick, gel-like fluid mostly made up of water; also contains salts, protein filaments (making up cytoskeleton), soluble proteins, and other organic molecules
- Location: Interior of cell; surrounds organelles
- Primary Function: Allows transport of substances within cell
Centrioles
- Structure: Composed of microtubules forming cylinders (often starburst-like in appearance)
- Location: Near nucleus in the centrosome
- Primary Function: Participates in cell division
- Structure: Composed of microtubules forming cylinders (often starburst-like in appearance)
- Location: Near nucleus in the centrosome
- Primary Function: Participates in cell division
- Structure: Short, slender projections in certain cells
- Location: Extended outward away from cell surface
- Primary Function: Motile cilia are used to propel fluids or small particles
Flagella
- Structure: Composed of bundles of fused microtubules
- Location: Tail-like appendage that protrudes through cell membrane to the exterior of the cell
- Primary Function: Movement of cell
Ribosomes
- Structure: Very small, spherical structures composed of RNA and protein
- Location: Often attached to the ER or unattached in cytoplasm
- Primary Function: Sites of protein synthesis
Rough ER
- Structure: Large, branching, membrane bound structure that may be flatted or tubular
- Location: Extends from nuclear envelope within the cytoplasm
- Primary Function: Sites of protein synthesis
Smooth ER
- Structure: Relatively large, membrane bound, branching structure that may be flatted or tubular; studded with ribosomes
- Location: Within cytoplasm
- Primary Function: Site of lipid and carbohydrate assembly
Golgi Apparatus
- Structure: Series or stacks of membrane bound, disc-shaped sacs
- Location: Within cytoplasm, usually near the nucleus
- Primary Function: Prepares and packages proteins for transport
Mitochondria
- Structure: Spherical or sausage-shaped structures; membrane bound
- Location: Throughout cytoplasm
- Primary Function: Site of cellular respiration where ATP is produced
Lysosomes
- Structure: Small, spherical structures; membrane bound
- Location: Throughout cytoplasm
- Primary Function: Contain enzymes that break down waste material and cellular debris
Vesicles
- Structure: Small membrane bound sacs
- Location: Throughout cytoplasm, usually near the Golgi apparatus
- Primary Function: Transport of materials within the cell
Cilia
- Structure: Short, slender projections in certain cells
- Location: Extended outward away from cell surface
- Primary Function: Motile cilia are used to propel fluids or small particles
Nucleus
- Structure: Large, often spherical structure surrounded by a double membrane (envelope)
- Location: Often located at the center of the cell
- Primary Function: Contains genetic material which regulates protein synthesis and cell division
Nucleolus
- Structure: Small spherical structure containing proteins and nucleic acids
- Location: Within the nucleus
- Primary Function: Site of RNA synthesis (transcription)
Nuclear Envelope
- Structure: Double membrane with large pores
- Location: Envelops the nucleolus and nucleoplasm
- Primary Functions: Provides selectively-permeable barrier; regulates movement of material in and out of nucleus
Nucleoplasm
- Structure: Gel-like fluid consisting of water, nucleic acids, and proteins
- Location: Contained within the nuclear envelope and surrounds chromosomes and nucleoli
- Primary Function: Contains material associated DNA and RNA synthesis
Chromatin
- Structure: Thread-like material composed of DNA and protein
- Location: Throughout nucleoplasm
- Primary Function: Genetic material which controls protein synthesis
Red Blood Cells
Specialize to allow space for transport of oxygen and carbon dioxide
White Blood Cells
Associated with your defense against disease and infection
Mitosis
The sequence of changes that separates the nucleus and the chromosomes (the latter already replicated during S period interphase) into two identical sets
Includes Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis
Diploid Cell
“Two”
-Each chromosome has its homologous copy
Identify the stages of mitosis
- Interphase
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
Interphase
- Distinct nucleus visible
- Two or more nucleoli
- Nuclear envelope intact
-Includes:
G1: Cell grow larger
S: Cell replicate chromosomes
G2: Cell prepare to divide
Prophase
- 1st step of Mitosis
- Condensing chromosomes become visible
- Spindle fibers appear
- Nuclear envelope disappears
Metaphase
- 2nd step of Mitosis
- Sister chromatids line up along the equator of the cell
- Spindle fibers are attached to the sister chromatids
Anaphase
- 3rd step of Mitosis
- Sister chromatids separate (now called chromosomes again) and move towards the opposite poles of the cell
Telophase
- 4th step of Mitosis
- The chromosomes have reached the opposite poles of the cell
- Spindle fibers disappear
- Nuclear envelope reforms
Cytokinesis
- 4th (if combined with Telophase) or 5th (if completely separate) step of Mitosis
- Begins while the cell is still in telophase
- A cleavage furrow forms across the middle of the cell, dividing the cytoplasm
- This will develop into the new plasma membrane for each daughter cell
Zygote
- Fertilized cell
- Receives half of each homologous pair of chromosomes from maternal source (egg) and half from paternal source (sperm)
Understand the process of meiosis and the final result
- Meiosis is specialized type of cell division that starts with a diploid cell, but produces reproductive cells called gametes (either egg or sperm)
- Each gamete has only one chromosome from each of the original homologous chromosome pairs, making them haploid cells
- Final Result: gametes (sex cells) that are haploid (containing only half of DNA homologous pair)
Understand the principles of genetic inheritance
- Variations in physical and behavioral characteristics of offspring result from the mixing of genetic information from the maternal and paternal sources
- Genes → Alleles (different versions of genes) → Dominant vs. Recessive → Phenotype and Genotype determined (Homozygous vs. Heterozygous too) → This all leads to what you inherit
Be familiar with the genetic traits discussed in lab
- Cleft Chin (it’s dominant)
- PTC Tasting (tasters are dominant)
- Color-blindness (it’s recessive)
- Ear Lobes (unattached is dominant)
- Tongue Rolling (the ability is dominant)
- Mid-digital Hair (Having hair is dominant
- Bent Little Finger (Bending is dominant)
- Interlocking Fingers (Left thumb over right is dominant)
- Hitchhiker’s Thumb (Having it is recessive)
Genes
- Units of inheritance
- Segment of DNA on a chromosome that determines the physical expression of a trait
Alleles
-Alternative forms of a gene
Dominant
An allele that completely masks the physical expression of another allele
Recessive
The allele not being expressed
Genotype
The two alleles that represent a gene
Phenotype
The physical expression of the genotype
Homozygous
- Genotype where two alleles are the same
- ”Homo” = “same”
Heterozygous
- Genotype consisting of two different alleles
- ”Hetero” = “different”
Incomplete Dominance
- Each copy of a dominant allele provides some expression
- One allele for a specific trait is not completely expressed over its paired allele, resulting in 3rd phenotype which express traits from both alleles
- Heterozygotes: thus a heterozygous individual only produces half the expression of a homozygous individual (one functioning protein, one nonfunctioning protein)
- Ex: Pure white flowers crossed with pure red flowers resulting in pink flowers
Polygenic Inheritance
The trait is influenced by multiple genes, potentially on different chromosomes
Understand the structure of DNA and the process of DNA replication
-DNA: Deoxyribonucleic acid; provides genetic blueprint that determines and controls living organisms; large double-stranded, helical molecule contains genetic instructions that direct assembly of protein molecules from simpler molecules
- Structure:
- Spends much of its time as stringy structure, but
- When cells prepare to divide, DNA forms into dense structures called chromosomes
- Composed of small units called nucleotides
- Replication:
- Step 1: An enzyme called a DNA helicase unwinds the DNA strands, separating the weak hydrogen bonds between the nitrogenous bases holding the two strands together
- Step 2: Another enzyme called DNA polymerase then builds a new complementary strand to each of the single “parent” strands
- Step 3: Result is two new DNA molecules each composed of one original parent strand and one newly synthesized strand
- DNA is replicated so that each daughter cell will get an exact copy
- Variety of enzymes and other factors are required for replication
Understand transcription and translation
- Transcription: Process of making mRNA; similar to DNA replication; requires a host of enzymes and other factors
- Translation: mRNA fits into a site on ribosome where its message is “read” by tRNA, which moves about the cytosol and acquire amino acids, placing them into the growing chain of amino acids until the protein coded by the mRNA is synthesized and released
Understand the differences between DNA, mRNA, and tRNA
DNA: Provides genetic blueprint that determines and controls living organisms
mRNA: Messenger RNA; it’s a copy of DNA; the process of making mRNA is transcription
tRNA: Transfer RNA; another type of RNA; “reads” the messages of mRNA and builds protein with amino acids
Understand the mutation that causes sickle cell anemia
It’s a mutations that changes a protein which results in some red blood cells forming sickled shapes (crescent moon shapes) instead of the normal biconcave (more circular) cells
Proteins
Structural and functional molecules that carry out most cellular activities, in essence the activities of life, including the synthesis of all other biological molecules
Nucleotides
- They compose DNA
- Their sequence code for protein
rRNA
- Ribosomal RNA
- Made up of the same nucleotides as mRNA, but instead of carrying the message of DNA, rRNA folds upon itself, creating ribosomes
Genetic Code
-In the form of three nucleotide sequences called codons
Codon
Three nucleotide sequence
-Each codon identifies a particular amino acid
Anticodon
Complementary code to a particular codon
Silent Mutations
A mutation that may not affect the protein produced
Mutation
An error in DNA
How do DNA and RNA vary in function?
DNA provides the genetic blueprint from which RNA synthesizes proteins
In what two ways does the chemical makeup of DNA and RNA vary?
DNA is in the nucleus and consists of bases ATCG. RNA is in the cell cytoplasm and consists of bases AUCG
What is the function of tRNA?
tRNA recognizes the mRNA sequence and assembles the appropriate amino acids to form a protein
Sickle cell anemia is a condition that has sickled blood cells instead of biconcave cells. This condition is a result of _____?
An abnormal protein that is formed by a mutation in the genetic code.
