BIOL 101 Lab Midterm

Process of science

Observation → Hypothesis → Experiment

Two types of observation

Subjective & Objective

Subjective Observation

observer specific and may not be interpreted in the same way by different people; plant is described as "tall," but tall doesn't mean the same thing to all observers. Tall in relation to what?

Objective Observation

observations that can be verified → repeated and consistently interpreted by different observers; involve counting and measuring

Hypothesis

a tentative explanation of cause and effect based on a underlying observed phenomenom (includes independent and dependent variable)

Independent Variable

The cause

Dependent Variable

The effect

Experiment

aims to alter the independent variable, hypothesized to be a causative agent, keeping all other factors constant (contains protocol and control)

Control

all the factors are the same as the test group, except that the factor being tested is left in its normal, unmanipulated state; factor that is associated with the independent variable which may influence (should be included in an experiment)

Protocol

description of steps in a scientific investigation

Can a hypothesis be proved?

A hypothesis may be disproved, but we refrain from saying that any hypothesis is proved. We rather say that our data supports our hypothesis.

Occam’s Razor

if there are several explanations that might fit an observation, the simplest is most probable and therefore best

causative agents

variables which are not being tested in the experiment which still may affect results

Agar

polysaccharide compound found in the cell walls of some red algae; designed to grow bacteria but such growth is not desirable in most of our environment

Prokaryotes

* Domain Bacteria and Archaea
* Unicellular organisms that lack membrane-bound organelles, including a nucleus
* Most abundant organisms in the world and are found in virtually every habitat.
* DNA is organized differently than that of all other organisms.
* Exist as single cells or as filaments or loose aggregation of cells.
* Reproduction is mainly asexual by simple reproduction

Nucleoid region (prokaryotic cell)

contains DNA for prokaryotic cells

Domain Bacteria Includes Two Groups

firmicutes and cyanobacteria (blue-green algae)

Cyanobacteria

Also referred to as blue-green algae; is a phylum of bacteria  that obtain their energy through photosynthesis, and are the only photosynthetic prokaryotes able to produce oxygen also contains chlorophyll a.

Chlorophyll a

the pigment blue-green algae possess

Role of Bacteria

Nitrogen fixation & Decomposers

Nitrogen Fixation (bacteria)

convert nitrogen from the atmosphere into forms that can be used by plants

Decomposers (bacteria)

Break down of dead plants or animals and return the organic materials to the system to be used by other organisms

Two types of autotrophic bacteria

Photosynthetic & Chemosynthetic Bacteria

Photosynthetic Bacteria

uses light as their energy source in a process similar to photosynthesis in a plant. However, they do not use water as source of electrons and lack chloroplasts

Chemosynthetic Bacteria

obtain their energy from the oxidation of inorganic substances

Three major groups of bacteria

Bacilli, Cocci, and Spirilla

Bacilli

rod-shaped

Cocci

small spheres

Spirilla

Corkscrew-shaped

Different Bacteria

Lactobacillus, Gloeocapsa, Oscillatoria

Lactobacillus

A type of prokaryote bacterium that consumes lactose and converts milk to yogurt, and are rod-shaped chains

Gloeocapsa

A type of prokaryotic cyanobacteria that is unicellular, often cluster, and has a gelatinous sheath

Gelatinous sheath

voluminous and fluffy sheaths found generally around  the cells in colonies of (cyanobacteria) and it holds the cells in colonies together

Oscillatoria

a type of prokaryotic bacteria that is a colonial blue-green algae that involves filaments, and photosynthesizes

Eukaryotes

* Domain Eukarya
* has cells with true nuclei and membrane-bound organelles such as endoplasmic reticulum, mitochondria, chloroplasts, and lysosomes
* It can be unicellular as a Protists or multicellular as in plants, animals, and fungi

Fungi

eukaryotic, heterotrophic, and generally multicellular

Saccharomyces (yeast)

Used to make alcohol and bread

Microscope

Kingdom Bacteria

* Staphylococcus
* Streptococcus
* Bacillus
* Coliform
* Pseudomonas

Staphylococcus

* forms 2-3 mm wide, moist-looking colonies
* opaque, off-white, or sometimes yellow
* gram-positive cocci

Streptococcus

* forms tiny colonies less than 1 mm wide
* transparent, barely off-white in color
* stains as a Gram-positive coccus
* common in nose and mouth
* cause of "strep throat"

Bacillus

* forms large colonies over 3 mm wide
* usually off-white, opaque, and often waxy-looking
* large, gram-positive bacillus
* spores may be visible as poorly stained oval swellings
* one of the most common genera of decomposers

Coliform

* typically 2-3 mm wide
* transparent, off-white
* foul-smelling
* quite wet-looking
* stains as small (almost too small to see) Gram-negative rods
* common in human intestines and in sewage

Pseudomonas

* similar to coliform but often form yellow-green, green, or blue-green pigment
* gram negative
* fairly common, can produce severe infections, especially in burn patients

Kingdom Protista

the most artificial of the five kingdoms; consists of a diverse array of unicellular, colonial, and multicellular organisms; any eukaryotic organism that is not an animal, plant, or fungus

Effect soap equation

(# colonies on unwashed side - # colonies on washed side/ # colonies on unwashed side (control) ) \* 100 = # bacteria removed from soap

Gram stain

technique to identify bacteria; fixation → crystal violet → Iodine treatment → Decolorization → counter stain with safranin

Diffusion

Molecules move from high concentration to low concentration until at equilibrium

Osmosis

Water moves from high potential to low potential until at equilibrium

Hypertonic

more solute outside of the cell → shrink

Hypotonic

less solute on the outside of the cell → swell/lyse

Plasmolysis

Cellular shrinkage in a hypertonic solution; Water flows out of the central vacuole

Different Protista

* Paramecium
* Euglena
* Amoeba
* Volvox

Paramecium

* Largest unicellular organism
* Phylum: Ciliophora
* Heterotrophic (cannot prepare their own food and depend upon autotrophs for nutrition)
* Move using cilia
* most complex protozoan

Phylum

the level of classification just below kingdom

Cilia

hair-like structures along the cell membrane over the entire body of the cell; used for locomotion and food capture -→ paramecium

Oral groove

rapid movement of cilia create water currents outside of cell that force fluids/food particles into this region; where a paramecium takes in food 

cytopharynx

lower end of the oral groove where food particles accumulate

food vacuole

formed as food particles accumulate at the cytopharynx; envelopes food particle

anal pore

opening where food vacuole migrates to when digestion is complete; this is where the food vacuole attaches and empties its contents

contractile vacuoles

a paramecium has two of these, typically one at the end of each cell, which remove excess fluids from the cell

Macronucleus

type of nucleus found in ciliates; controls cell maintenance functions

Micronucleus

type of nucleus found in ciliates; responsible for genetic and reproductive functions, including producing the macronucleus

conjugation

during this process in ciliates, two cells exchange micronuclei and thus genetic material; each cell acts as both "donor" and "recipient"

Euglena

* Unicellular, Phylum: Euglenophyta, Photosynthetic, heterotrophic, phagocytosis; Move using flagella

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Pellicle

a layer of elastic proteins just inside the cell membrane

flagellum

A whiplike structure that emerges from a canal or invagination at the anterior end of the cell in euglena and volvox

stigma

located just interior to the flagellum; a light-sensitive structure containing pigments known as carotenoids

pyrenoids

organelles that are involved in carbon fixation and starch formation and storage

Volvox

* Colonial, Phylum: Chlorophyta, Photosynthetic, closely related to plants, Biflagellate

cytoplasmic strands

volvox outer cells are connected to one another by these

daughter colonies

produced by reproductive cells inside the parent Volvox, released when the parent colony bursts

Amoeba

* Unicellular
* Phylum: amoebozoa
* Heterotrophic
* Move and eat using pseudopods

pseudopodia movement

form of cell motility that uses microtubules in a different manner; cells use pseudopodia (false feet) which extent from the body and then pull the rest of the cell along

PLants

multicellular eukaryotic organisms that are characterized by a cell wall made of cellulose, a complex carbohydrate polymer and by  unique double membrane bound organelles, plastids

plastids

unique double membrane-bound organelles that performs a variety of functions including manufacturing and storage of food

Endosymbiont Theory

theory that explains the relationships between chloroplasts and the cells in which they reside; states that chloroplasts (and mitochondria) were originally themselves prokaryotic cells that were engulfed by, and through evolution, developed a symbiotic relationship with their host cells

Elodea

* Plantae Kingdom
* Phylum: Magnoliaphyta
* Multicellular
* Photosynthetic
* Plasmolysis (saltwater)
* eukaryotic
* movement: cytoplasmic streaming
* visible organelles: cell wall, MANY chloroplasts

cytoplasmic streaming

chloroplasts suspended in cytoplasm moving throughout the cell

plasmolysis

cellular shrinking due to a cell being exposed to a hypertonic solution

Human Epithelial Cells

* Kingdom Animalia (multicellular, heterotrophic eukaryotic organisms that lack cell walls)
* Phylum: Chordata
* eukaryotes
* multicellular
* movement: cells are tightly packed together; specialized to allow materials to pass between cells or through cells

Photosynthesis Formula

H20 + CO2 → (light) (CH2O)N + O2

\
6CO2 + 6H2O → light C6H12O6 + 6O2

Thylakoid Membrane

located in the chloroplasts and where the absorption of light

stroma

where carbohydrate formation or "synthesis" reactions taken place; fluid within the chloroplasts that surrounds the thylakoids

Photoreceptors

absorb light energy

chromtagraphy

pigment

Spectrophotometry

→ Rate of light reaction

Chlorophyll a

blue-green, all photosynthetic eukaryotes and cyanobacteria

Chlorophyll b

olive green, in most plants

Chlorophyll c

in some types of algae

β-Carotene

yellow-orange; Carotenoid

Xanthophylls

yellow; Carotenoid

Rf equation

distance substance travels from origin/ distance solvent travels from origin; reflects the relative affinity a substance has for the solvent; an indicator of what pigment you have

Chromatogram

* a complete array of colored bands
* when separation is complete, pigment bands can be identified by their colors and relative positions on the chromatogram

Paper is…

polar

Solution is….

nonpolar

likes like likes

Polar pigments like polar solution and nonpolar pigments like nonpolar solution

* High rf →
* Lower rf →

* nonpolar
* polar

rate of photosynthesis formula

%light transmittance/time