Lab Exam 1 Flashcards
define compound microscope
uses multiple lenses
how do you calculate total magnification
multiplying objective lens magnification and ocular lens magnification
define eyepiece reticle
scale projected over the image to estimate the size
define resolution
shortest resolvable distance between two objects under the microscope
which lens is responsible for most of the magnification and resolution of the microscope
objective lenses
what parts of the microscope are responsible for producing and shaping the light
- light source
- field diaphragm
- aperture
- condenser
define science
- from latin word meaning knowledge
- covers general truths or the operation of general laws, especially when acquired and tested by the scientific method
what is the first step in the scientific process
observation
define hypothesis
suggested explanation for an event which one can test
what must a valid hypothesis be
- testable
- falsifiable
can a hypothesis be proven
no
define variable
any part of an experiment that can vary or change during the experiment
define independent variable
variable being manipulated or changed
define dependent variable
variable being measured
define control variable
variables held constant to not influence outcome
define control group
- contains every feature of the experimental group except it is not given the manipulation
- ensures results are due to the manipulation
- baseline to compare results
steps of the scientific method
- observation
- question
- hypothesis
- prediction
- experiment
- analyze results
- support or reject hypothesis
- report results
how do termites communicate
pheromones
characteristics of a compound light miscroscope
- uses two sets of lenses
- views thin sections
- illumination from below
- greater magnification than dissecting microscope
characteristics of a dissecting microscope/stereoscope
- views objects in 3D
- opaque objects viewed with reflected light
- less magnification than compound microscope
characteristics of an electron microscope
- beam of electrons used
- greater magnification and resolution than light microscopes
- magnification up to 100,000X
what is the difference between transmission electron microscopes and scanning electron microscopes
- transmission: view thin sections such as cellular organelles
- scanning: view 3D surface of objects
what is the most common magnification for the ocular lens
10X
what are the most common magnifications for the objectives lenses
4X, 10X, 40X, 100X
what happens to the field of view as you increase magnification
it decreases
what happens to the depth of field as you increase magnification
it decreases
what are differences between light microscopes, dissecting microscopes, and electron microscopes
- light: use light to produce image, views thin sections, intermediate magnification
- dissecting: use light to produce image, views objects in 3D, lowest magnification
- electron: use beam of electrons to produce image, can view thin sections or 3D surfaces, highest magnification
define biomolecules
- large molecules
- necessary for life
- built from smaller organic molecules
what are the four major biomolecule classes
- carbohydrates
- lipids
- proteins
- nucleic acids
what is the ratio of carbon to hydrogen to oxygen in carbohydrates
1:2:1
what are the 3 subtypes of carbohydrates
- monosaccharides
- disaccharides
- polysaccharides
what is the most common monosaccharide
glucose
how may carbons are in monosachharides
3 to 7
how are disaccharides created from monosaccharides
dehydration synthesis
what are some common disaccharides
- lactose: glucose and galactose
- maltose: glucose and glucose
- sucrose: glucose and fructose
examples of polysaccharides
- starch
- glycogen
- chitin
what are the main functions of carbohydrates
- energy
- energy storage
- structure
are lipids polar or nonpolar
- nonpolar
- hydrophobic
what is the structure of triglycerides
- glycerol
- 3 fatty acids
what are the main functions of lipids
- energy storage
- insulation
- metabolize vitamins
- growth and development
- protection
- hormones
- cholesterol
what is the most common type of lipid
fats/triglycerides
which type of fat is bad and why
- saturated fats
- have only single bonds
- saturated with H
- can pack tightly
- solid at room temperature
which macromolecule has the most diverse range of functions
proteins
functions of proteins
- enzymes
- transporting molecules
- structure
- hormones
- immune response
- cell adhesion
what are proteins made from
amino acids
define enzymes
- catalyst in biochemical reactions
- complex protein
- each is specific for a substrate
define catabolic enzymes
break down substrates
define anabolic enzymes
build more complex molecules from substrates
define hormones
- chemical-signaling molecules
- usually small proteins or steroids
- regulate growth, development, metabolism, reproduction
what is the most important macromolecule for the continuity of life
nucleic acids
functions of nucleic acids
- carry cells genetic blueprint and instructions for functioning
- heredity
what are the two main types of nucleic acids
- DNA
- RNA
define dehydration synthesis
- how biomolecules are built
- bonds formed through the removal of water
- remove OH from one group and H from another
what bonds are formed between monosaccharides after dehydration synthesis
glycosidic bonds
what bonds are formed between glycerol and fatty acids after dehydration synthesis
ester linkages
what bonds are formed between amino acids after dehydration synthesis
peptide bonds
why are the bonds between monomers of biomolecules important
test for presence of bonds to see if a biomolecule is present in a solution
benedicts reagent: what does it test for, what is the positive color, what is the negative color
- tests for monosaccharides
- positive: low amount is green, high amount is orange/red
- negative: blue
lugol’s solution: what does it test for, what is the positive color, what is the negative color
- tests for polysaccharides/starch
- positive: dark blue/black
- negative: orange/brown
biruret’s test: what does it test for, what is the positive color, what is the negative color
- tests for proteins
- positive: violet
- negative: pale blue
sudan IV test: what does it test for, what is the positive color, what is the negative color
- tests for lipids
- positive: red
- negative: clear, dye sinks to bottom
which test for biomolecules must be heated
- benedicts reagent
- tests for monosaccharides
what is the smallest unit of a living thing
cell
what is the level of organization from cell to organism
- cell
- tissue
- organ
- organ system
- organism
what are 3 ways we can classify cells
- number: unicellular or multicellular
- photosynthesis ability: plant or animal
- presence of membrane-bound organelles: prokaryote or eukaryote
what four things do all cells share (prokaryotic and eukaryotic)
- plasma membrane
- cytoplasm
- DNA
- ribosomes
unique features of prokaryotes
- mostly unicellular
- lack nucleus or any other membrane bound organelles
- most have a peptidoglycan cell wall
- many have a polysaccharide capsule
- some have flagella or pili
what is the cell theory
- cells are the smallest unit of life
- all living things are made of one or more cells
- all cells come from pre-existing cells
function of the plasma membrane
- protects cell
- selectively permeable: allows certain things to enter or exit cell
function of the cytoplasm
- surrounds cells internal structures
- where metabolic reactions take place
function of nucleus
- holds genetic material (DNA)
- controls cell activities
- nucleolus: produces ribosomes
function of ribosomes
- synthesize proteins
function of cytoskeleton
- fibers that give support to cell and organelles
- aids in movement
functions of mitochondria
- produce energy
- site of cellular respiration
functions of vesicles/vacuoles
- storage
- transport
functions of lysosomes
- only in animal cells
- digestion and removal of cell waste
functions of endoplasmic reticulum
- RER: modifies proteins, synthesizes phospholipids
- SER: synthesizes carbs and lipids, detoxification
functions of golgi apparatus
- receives items from endoplasmic reticulum through vesicles
- sorts materials to determine where to send them
functions of cell wall
- protection
- maintains cell shape
functions of chloroplast
- only in plant cells
- make glucose through photosynthesis
functions of cilia and flagella
cell movement
unique features of eukaryotes
- have membrane bound organelles
- have nucleus
- have several rod shaped chromosomes
define plasma membrane
- phospholipid bilayer with embedded proteins
- controls passage of substances in and out of the cell
define diffusion
- passive transport
- substance moves from high to low concentration
define osmosis
- movement of water from area of low solute to high solute concentration
define hypertonic solution
- higher solute concentration outside of the cell
- water moves out of cell
- cell shrinks
define hypotonic solution
- lower solute concentration inside the cell
- water moves into the cell
- cell bursts
what is included in cytoplasm
- cytosol
- cytoskeleton
- various chemicals
define cytoplasmic streaming
movement of cytoplasm within the cell to transport nutrients, proteins, and organelles throughout the cell
which lipid is found within the plasma membrane and affects membrane fluidity
cholesterol
what organelles are specific to animal cells
- centrioles/centrosomes
- lysosomes
what is the purpose of cell division
- growth
- maintenance and repair of cells
- reproduction for single celled organisms
what are the two major phases of the cell cycle (mitosis)
- interphase
- mitotic phase
what happens during interphase
- G1: cell growth, protein synthesis, energy reserves
- S: DNA replicated and attached at centromere, centrosomes duplicate and give rise to mitotic spindle
- G2: cell growth, protein synthesis, replenish energy reserves, organelles duplicated, cytoskeleton dismantled
what happens during the mitotic phase
- duplicated chromosomes are aligned, separated, and moved to opposite sides of the cell
- cell divided into two identical daughter cells
what are the two parts of the mitotic phase
- mitosis
- cytokinesis
what happens during mitosis
- 5 stages
- nuclear division
what happens during cytokinesis
physical separation of cytoplasmic components into 2 cells
what happens during prophase
- nuclear envelope breaks
- centrosomes move to opposite ends of the cell
- spindle fibers emerge from centrosomes
- sister chromatids coil tightly and become visible under microscope
what happens during prometaphase
- chromosomes continue to condense
- kinetochores appear at centromeres
- microtubules attach to chromosomes at kinetochore
what happens during metaphase
- chromosomes align at metaphase plate
- sister chromatids still attached to each other and spindle fibers
- chromosomes maximally condensed
what happens during anaphase
- sister chromatids (now called chromosomes) pulled apart at centromere towards a centrosome
- spindle fibers elongate the cell
what happens during telophase
- chromosomes at opposite ends begin to decondense
- mitotic spindles broken down to assemble cytoskeleton
- nuclear envelope begins to form around chromosomes
what happens during cytokinesis in animal cells
- contractile ring composed of actin filaments forms at former metaphase plate
- actin filaments pull inward forming a fissure known as the cleavage furrow
- furrow deepens until cell is split
what happens during cytokinesis in plant cells
- enzymes, proteins, and glucose move into vesicles during interphase
- vesicles collect at metaphase plate during telophase
- vesicles fuse to form a cell plate
- enzymes use glucose to build new cell wall of cellulose
what is the G0 phase
- cells not actively preparing to divide
- some enter temporarily
- some never or rarely divide and remain in G0 permanently (mature cardiac muscle and nerve cells)
which phase takes up the majority of the time during the cell cycle
interphase
what type of cells does mitosis produce
genetically identical cells
what is the purpose of meiosis
to produce haploid gametes for sexual reproduction
what happens during prophase 1
- chromosomes seen microscopically
- nuclear envelope breaks down
- homologous chromosomes move towards each other
- synapsis: tight pairing of homologous chromosomes
- crossing over: genes on non-sister chromatids are aligned and segments are exchanged
what is the first source of genetic variation produced by mitosis
crossing over in prophase 1
what happens during meiosis 2
- connected sister chromatids will split to form 4 haploid cells
- chromosomes are not duplicated
- resembles mitotic division
differences between mitosis and meiosis
- mitosis: one division, results in 2 diploid cells that are genetically identical, does not have synapsis or crossing over
- meiosis: two divisions, results in 4 haploid cells that are genetically unique, synapsis and crossing over in prophase 1
what are the cells that meiosis makes called
gametes
why is meiosis 1 referred to as a reduction division
- number of sets of chromosomes is reduced from 2 to 1
- diploid to haploid
define diploid
- cells with 2 copies of DNA
- body cells
define haploid
- cell with a single copy of DNA
- gametes (sperm and ovum)
who is sometimes referred to as the father of genetics and why
- gregor mendel
- observed traits in peas
- determined individuals have alternate forms of genes called alleles
what is the difference between genotype and phenotypes
- genotype: alleles present for each gene; AA
- phenotype: individual’s appearance (can be influenced by environment); purple flower
define the law of segregation
- genes segregate into gametes so that offspring have an equal likelihood of inheriting either factor
- gametes only carry one allele for a gene
define law of independent assortment
- genes do not influence each other during gamete formation
- every combination of alleles is equally likely to occur
are dominant traits always more common
- no
- dominant alleles may be rarer in a population
what is the phenotypic ratio for offspring from two heterozygous individuals in a dihybrid cross
9:3:3:1
what is the phenotypic ratio for offspring from two heterozygous individuals in a monohybrid cross
3:1
what antigens are on each blood type
- A: A
- B: B
- AB: A and B
- O: none
define codominance
- neither allele is recessive
- both phenotypes are expressed
- red cow mates with white cow and produce red and white spotted cow
define incomplete dominance
- two alleles produce intermediate phenotype
- red flower mates with white flower and produce pink flower
what happens when chromatids don’t separate properly during meiosis 2
- genetic disease
- non disjunction
- ex: down syndrome
example of how the envrionment affect phenotypes
- plant has alleles that favor large growth rate
- with good soil and water the plant with grow large
- with poor soil and water the plant will be small
is most of out DNA the same or different
the same
