Bio Lab Exam Study Guide

Main Lab Rules

No eating, drinking, or gum chewing in the lab

smoling is prohibuted in all gs buildings

do not pull the shower handle unless emergy if u do w/o emergency you will be expelled from course

dress code/ pants, closed toe shoes, and shirts with sleeves

-if u come unprepared you will be asked to leave lab

no drink or food allowed in class

no unauthorized or unsupervised experiments are permitted

how to properly dispose of biohazard waste

dispose of glass and biohazard materials in their specified containers

Length

the measurement of something from end to end. The basic unit of length is the meter

mass

the amount of matter in an object. The basic unit of mass is the gram (g)

Volume

The amount of three-dimensional space an object or liquid occupies. The basic unit of liquid volume is the liter L

Meniscus

the curve seen at the upper surface of a liquid in a container. it is caused by surface tension and adhesion.

How to read a meniscus

always read the volume at the bottom of the meniscus curve while keeping your eyes at eye level with the liquid

temperature

a measure of the average kinetic energy of the particles in a substance (how hot or cold it is) the basic unit of temp in science is celsius C or Kelvin

Temp conversion formulas

Celsius to Fahrenheit: F=(C x 9/5)+32

Farenheit to Celsius C= (F-32) x 5/9

The scientific method

a plan or method for asking questions and testing possible explanations through systematic observation and experimentation

Steps of the scientific method

observation/ noticing and describing a phenomenon or process

question/ asking a specific, defined question about the observation

hypothesis/ a tentative, testable, and falsifiable explanations for the observation

prediction/ an expected outcome statement, usually phrased as an if then statement

experiment/ a-controlled procedure designed to test the hypothesis and collect data

analysis/conclusion/ interpreting the data collected to determine if it supports or rejects the hypothesis.

Independent variable

the factor that the researcher deliberately changes or manipulates

dependent variable

/ the factor that is measured or observed; it changes in response to the independent variable

Controlled variables

all factors kept identical between experimental groups to ensure a fair test

experimental group

the group that receives the specific treatment being tested

control group

the baseline group that does not receive the treatment, used for direct comparison

replication

repeating an experiment multiple times to ensure results are reliable, consistent, and not due to random chance.

sample size

the number of individual subjects or observations in an experiment; larger sample sizes provide more accurate and statistically significant results

calculating means (averages)

add all the individual data values together, then divide by the total number of values

line graph

used to show trends, continuous data, or changes over time

bar graph

used to compare distinct, categorical groups or discrete data sets

extertion relationship

physical exertion increases the bodys demand for energy and oxygen. To meet this demand, the cardiovascular system works harder and the pulmanory system works harder.

measuring pulse rate

count the number of heartbeats felt for 30 seconds then multiply by 2

measuring respiratory rate

count the number of full breaths (one inhalation and one exhalation equals one breath) taken by a subject during a 30 second interval, then multiply by 2 to find breaths per minute.

monomers

single, small molecular subunits that serve as the building blocks for larger molecules

polymers

large molecules formed by bonding multiple monomers together in chain

condensation reaction (Dehydration Synethis)

a chemical reaction that links monomers into polymers by removing a water molecule

Carbohydrates

monosaccharides/short term energy storage and structural support/ test is gram iodine for starch and benedicts for reducing sugars

lipids

glycerol and fatty acids/long term energy storage, cell membrane structure/ Sudan IV Staining

Proteins

Amino acids/ enzymatic activity, cellular transport, structural support/ Bradford Assay

Nucleic Acids

Nucleotides/ storing and transmitting genetic information, n/a

gram iodine test

target; detect starch, positive result turns a blue, purple, or black color, and its a qualitative assay

benedicts test

target; reducing sugars, low concentration positive appears yellowish green, high concentration positive; appears orange, red, or brown, type qualitative assay

Sudan IV Staining

target; detect lipids; mechanism is a nonpolar fat soluble stain that dissolves in lipids but not in water, type of test is qualitative assay

Bradford Assay

target; detects proteins using Coomassie Brilliant Blue G-250 dye, positive result color will shift to blue w the intensity correlating to protein concentration

type; both qualitative (visual color intensity) and quantitative (spectrophotometer absorption readings)

Positive control

; a sample known to contain the target macromolecule. It endures the reagents are functioning correctly

negative control

a sample lacking the target macromolecule (usually distilled water) it provides a baseline for a zero/negative result.

qualitative analysis

observes non numerical properties, such as a visual color change

quantitative analysis

measures precise numerical values, such as absorbance data from a spectrophotometer

standard curve

a graph plotting known concentrations of a substance (like bovine serum albumin/bsa for proteins) against their absorbance values. This baseline curve is used to calculate the exact concentration of unknown samples.

What is DNA?

deoxyribonucleic acid; the molecule that carries genetic instructions for the development, functioning, growth, and reproduction of all known organisms

structure

a double helix composed of two antiparallel strands made of nucliotide subunits. each nucleotide consists of a deoxyribose sugar, a phosphate group, and a nitrogranous base

histones

specialized proteins around which dna winds to form nuclosomes. They help condense and organize structural chromatin so it fits inside the cell nucleus

Where is DNA located

In eukaryotic cells (like plant and human cells) DNa is primarily located in the nuclus.

Why should DNA be extracted?

To isolate DNA from membranes, proteins, and other cellular components for analysis

Steps; mashing the fruit (mechanically open cell walls to increase the surface area for chemical reactions)

Adding liquid dishwashing soap; lyses (breaks down the lipid based plasma and nuclear membranes to release DNA into solution.

Placing mixture in the ice bath; slows down strctural breakdown and inhibits DNase enzymes that would otherwise destroy the DNA

Filtration process; seperates large cellular debris, cell walls, and unmashed tissues from the liquid solution containing the DNA

Enzyme solution

contains proteases that break down and digest histones and other proteins bound to the DNA

ice cold 95% ethanol (or isopropanol)

DNA is insoluble in alcohol. Precipitates DNA out of the aqueous solution, making it visible as white, stringy fibers.

What are genes

specific segments of DNA that contain instructions for making proteins

connection

the genotype is the actual genetic makeup alleles, which serves as the blueprint. the phenotype is the physical expression or visible trait resulting from that genotype interacting with the environment

What are genetic traits

heritable characteristics passed from parents to offspring through genes

dominant vs recessive

dominant alleles mask the expression of recessive alleles. a recessive trait only shows if an individual has two copies

homozygous vs heterozygous

homozygous means having identical alleles. heterozygous means having two different alleles

what are chromosomes

thread-like structures made of tightly packed DNA and histones located in the nucleus

sx chromosomes

chromosomes that determine biological sx

autosome chromosome

the remaining non sx chromosomes (humans have 22 pairs of autosomes)

What is a genetic disorder

A disease or condition caused by an abnormality, mutation, or structural change in an individual’s DNA sequence.

achondroplasia

a genetic disorder inherited in an autosomal dominant manner that result in the most common form of short-limbed dwarfism

albinism

a group of inherited disorders characterized by little to no production of the pigment melanin, affecting the coloration of skin, hair, and eyes

Trisomy 21 (Down Syndrome)

a chromosomal disorder caused by the presence of a third copy of chromosome 21, resulting in distinctive physical features and developmental delays

trisomy 18 (edwards syndrome)

A severe chromosomal condition caused by an extra copy of chromosome 18, characterized by severe developmental delays and congenital structural abnormalities.

turner syndrome

a condition affecting females where one of the X chromosomes is completely or partially missing, leading to short stature and infertility

nondisjunction

an error in cell division during meiosis where homologous chromosomes or sister chromatids fail to seperate properly. This event produces gametes with abnormal chromosome numbers, leading to conditions like Trisomy 21, 18, and turner syndrome.

karyotype

is a laboratory photograph of an individuals complete set of chromosomes, isolated from a cell and arranged in pairs by size, shape, and banding patterns.

how to read a karyotypes

to read a karyotype, count the total number of chromosomes to check for numerical abnormalities. Then examine the 23rd pair to determine the biological sx

total magnification

total magnification is the overall enlargement of the specimen being viewed through the microscope

Field of View

field of view is the maximum diameter of the circular area that you can see when looking through the microscope eyepiece

Steps to prepare a wet mount slide

1/ place specimen- put a small drop of liquid or your sample in the center of a clean, blank slide

2/ add dye (if needed)- place a drop of stain (like methylene blue or iodine) onto the specimen.

3/ Angle the coverslip- hold a clean coverslip at a 45 degree angle with its bottom edge touching the edge of the liquid drop

4/lower slowly- gently lower the coverslip onto the slide. This prevents air bubbles from getting trapped beneath it.

Steps to Examine a prepared slide

stage placement; clip the slide securely onto the mechanical stage

lowest power first; always start w the lowest power objective lens

course focus; use the coarse adjustment knob to raise the stage while looking from the side; then look through the eyepiece and adjust until the image appears

fine focus; switch to the fine adjustment knob to sharpen the image clearly

switch objectives; center your specimen in the field of view before rotating to a higher power objective lens, and only use the fine focus knob at the higher powers to avoid cracking the slide.

biodiversity

the variety of life found within a specific ecosystem or habitat

species richness

the total number of different species present in a community. It does not account for how many individuals of each species exist.

species abundance

the relative representation of a species in a particular ecosystem

species evenness

a measure of how equality distributed the individual organisms are among the different species in a community

s[ectrophotometer

measures the amount of light absorbed or transmitted by a liquid sample to determine concentration

cuvette

a small, square shaped tube designed to hold liquid samples inside a spectrophotometer

microcentrifuge tubes

small plastic conical tubes used to hold, mix, or spin don tiny volumes of liquid samples

vortex mixer

a device used to rapidly mix small vials or tubes of liquids using an oscillating motion

transfer pipettes

disposable plastic tools used to roughly transfer small amounts of liquid without precise volumetric markings

serological pipettes

long graduated glass or plastic tubes fitted to a pump used to measure and transfer precise volumes of liquids