Category: 1st Semester

Human Hand Adaptations

 

Human Hand Adaptation

Introduction:        Living things have bodies that are adapted for the places they live and the things they do. Fish have gills so that they can remove oxygen that is dissolved in water. Most plants have green leaves which contain chlorophyll so that they can make food. Jellyfish have stinging cells to capture prey. Birds have hollow spongy bones so that they will be light enough to fly. Arctic animals have layers of fat and thick coats of fur to keep warm in the frigid Arctic climate. There are hundreds of examples of ways that organisms are adapted for a successful lifestyle.       Humans, too, are adapted for the things they do. One of our adaptations is our hand. Humans, as well as monkeys, gorillas, and other primates, have a hand that can grasp objects. We are able to grasp objects because of our opposable thumb. When students first hear or read about the opposable thumb during discussions of human evolution, they may perceive it as an anatomical fact with little seeming importance. In this activity, students will discover which of their simplest daily activities are possible only because of their opposable thumbs, which activities take longer without the use of an opposable thumb, and what sort of human activities would not be likely in the absence of an opposable thumb.   In this lab exercise, you will perform several common actions. Then you will change your hand so that it resembles that of a non-primate animal. You will determine whether or not you can successfully perform the same actions. This will demonstrate how the human hand is adapted for the actions it performs. You will work with a partner to do this exercise.   Materials: (per group)

  • masking tape
  • scissors
  • paper clips
  • zip-lock storage bag
  • plastic fork and knife
  • small amounts of food items to be cut
  • pencil
  • jar with screw-on lid
  • paper
  • roll of tape
  • balloons
  • comb
  • book
  • lace-up shoe
  • clock with a second hand
  • Piece of yarn or string
  • balloon
  • clothes with zippers & buttons

Procedure: Using masking tape, have your partner tightly tape each of your thumbs to the palm of the hand. Then, try to complete the tasks that are listed below. Be careful not to use your thumbs. Have your partner record on your data table how long it takes to do each task with your thumb taped and then with your thumb free. If an activity takes longer than 2 minutes, record the event as unsuccessful . After completing each item, write out the answers to the following questions:

  • Is the task more difficult with or without an opposable thumb?
  • How did you have to change your usual technique in order to complete this task?
  • Do you think organisms without opposable thumbs would carry out this task on a regular basis? Why or why not?

Tasks:

  1. Pick up a single piece of paper. Put it down on your desk.
  2. Pick up a pen or pencil from the table top. Use it to write your name on the piece of paper.
  3. Open a book. Turn single pages in the book.
  4. Unscrew a bottle cap or jar cover.
  5. Use a fork and knife to cut a food item into small pieces.
  6. Tear off a small piece of tape.
  7. Turn on the water faucet. (Complete activity #8!) Turn it off.
  8. Moisten a paper towel and wash and dry the desktop.
  9. Sharpen a pencil.
  10. Cut a circle out of a piece of paper using scissors.
  11. Pick up all the scraps from activity #10 and throw them into the recycling box.
  12. Comb your hair.
  13. Open a door.
  14. Pick up one paper clip. Clip a pile of papers together.
  15. Tie your shoelaces.
  16. Button several buttons.
  17. Zip up your jacket.
  18. Blow up a balloon and tie it.
  19. Tie a knot in a piece of string.
  20. Close a zip-lock bag.

Data:

Table 1 – Time It Took To Perform Various Tasks

 

Task Time Taken for Event: Task Difficulty With Taped Thumb
(More/Less)		 Modification Made to complete Task
Thumb Free Thumb Taped
Pick up paper
Write name
Turn book pages
Open jar
Use knife & fork
Tear off tape
Turn faucet on & off
Clean desk top
Sharpen a pencil
Cut out a circle
Pick up the scraps of paper
Comb hair
Open door
Clip papers together
Tie shoelaces
Button & unbutton garment
Use zipper
Blow up & tie balloon
Knot string
Close zip-lock bag

Conclusion:   1. Explain why dog and cat paws are not adapted for doing the six actions you tested.     2. What are cat and dog paws adapted for?     3. Describe how your hand is adapted for doing the actions you tested.       4. You have an opposable thumb. Explain what this means.     5. Why do you feel that human hand adaptations have helped to make humans such a successful species on earth?

 

Ink Chromatography

Chromatography of Inks

Introduction:

One of the main jobs of biochemists is to unravel the complexities of chemical compounds and reduce them to their individual components.  The term chromatography comes from two Greek words, “chromat” meaning color and the word “graphon” meaning to write.  Separation of the components of chemical compounds can be done by using several methods. Liquids can be separate by High Performance liquid Chromatography (HPLC), while the components of gases are separated by Gas Chromatography.  Chromatography is a method for analyzing complex mixtures (such as ink) by separating them into the chemicals from which they are made. Chromatography is used to separate and identify all sorts of substances in police work. Drugs from narcotics to aspirin can be identified in urine and blood samples, often with the aid of chromatography.

Chromatography was first used to separate pigments (colors) in leaves, berries, and natural dyes. Paper chromatography is a technique used to separate, isolate, and identify chemical components of a compound. In paper chromatography, the solid surface is the cellulose fibers in the chromatography paper.  A solvent or developer (water, alcohol, or acetone) is placed in the bottom of the chromatography chamber. The paper acts as a wick to pull the solvent up the paper. The solvent front will “wick” up the chromatography paper by capillary action.  A minute drop of the ink or chemical mixture to be separated is placed near the bottom of the strip of chromatography paper, but slightly above the level of the solvent in the chamber.  As the solvent passes over the drop of ink, the components of the ink dissolve in the solvent. Because the components of the ink do not all dissolve at the same rate, as the components of the mixture move upward, they show up as colored streaks.  The separated substances on the chromatography paper form a color pattern called a chromatogram.

To determine the rate of migration for each pigment or component of the ink, the Rf value for each pigment must be calculated. The Rf value represents the ratio of the distance a pigment moved on the chromatogram relative to the  distance the solvent front moved. Each pigment or compound will have a unique Rf value that scientists can use to identify the substance. The Rf value is calculated using the following formula:

Rf = distance traveled by the compound / distance traveled by the solvent

Objective:

Use the process of paper chromatography to separate the pigments in various markers and then determine the Rf value for each color on your chromatogram.

Materials:

Plastic vials, paper clips, markers in assorted colors, chromatography paper, scissors, pencil

Procedure:

  1. Obtain chromatography vials and chromatography strips, and different color markers so that each person in the group will have two chromatograms.
  2. Cut one end of the chromatography strip to a point. The bottom of the point will mark the starting point for movement of the solvent (H2O).
  3. About 2.0 centimeters from the bottom of the strip, draw a faint horizontal line with pencil. This will mark the starting point for measuring the migration distance of each color.
  4. Using a different color marker for each strip, drop a dot of ink on the center of the horizontal pencil line.  Let this dry a moment & then add more ink to the dot.
  5. Add a small amount of water to the bottom of the chromatography chamber. (The ink dot should be ABOVE the surface of the water.)
  6. Straighten a paper clip and poke a hole through the top of your chromatography strip
  7. Use the paper clip to hang the strip in your chamber. (The straighten paper clip will lay across the top of the chamber.)
  8. MAKE SURE THE TIP OF THE STRIP BUT NOT THE INK IS IMMERSED IN THE WATER!
  9. Notice the separation of the ink as both the solvent and ink travel up the chromatography strip.
  10. Once the solvent front has neared the top of the strip, remove the strip from the chamber and lay it on a piece of paper towel.
  11. Immediately mark the solvent front with a faint pencil line.
  12. Immediately mark the leading edge of each color with an “x”.
  13. Measure, in millimeters, the distance the solvent migrated from the tip of the strip to your solvent front pencil line.
  14. Measure, in millimeters, the distance each color migrated from the point of origin (pencil line where the ink dot was placed) to the leading edge of the color (marked with an “x”.
  15. Record all data in Data table 1.
  16. Calculate and record the Rf value for each color using the formula below.

Rf = distance traveled by the compound / distance traveled by the solvent

Data Table 1

 

Color pen/marker used:

Separated colors
(list top of strip to bottom) 		Distance each color traveled

(mm)

Distance solvent (H2O)
(mm) 		Rf Value for each color

(Distance color traveled / Distance solvent traveled)

       
       
       
       
       
       
       
       

 

 

 

Color pen/marker used:

Separated colors
(list top of strip to bottom) 		Distance each color traveled

(mm)

Distance solvent (H2O)
(mm) 		Rf Value for each color

(Distance color traveled / Distance solvent traveled)

       
       
       
       
       
       
       
       

 

 

Questions:

1. Which color of marker did you use?

2. which color separated out first from your ink dot?

3. Why did the inks separate?

 

4. What was your solvent?

5. If you had used markers that weren’t water-soluble, how would you have had to change this lab?

 

6. Why did some inks move a greater distance than others?

 

7. How do scientists use paper chromatography in their investigations?

 

 

Gene Expression

 

Gene Expression [18,787 bytes]

 

 

Section 11-1     Control of Gene Expression

 

1. Cells use ______________________ to build hundreds of different________________each with a unique ____________________________.

2. Are all proteins used by a cell at any one time? If not, how do cells control this?

3. Define gene expression.

4. When are proteins produced?

5. What is the genome?

6. What are the 2 steps of gene expression?

7. What 2 scientists determined how genes are expressed in prokaryotes?

8. What gene & in what organism did Jacob & Monod make their discoveries about gene expression?

9. Name the 3 regulatory elements on the DNA of the E. coli bacterium and tell the function of each.

10. What is an operon & what 3 things is it made up of?

11. What name did Jacob & Monod give their gene & why?

12. If lactose is not present, what attaches to the operator?

13. Define repressor protein and give its function.

14. Define repression.

15. What occurs if lactose is present in the E. coli in lactose metabolism?

16. What is an inducer?

17. What is an inducer for E. coli in lactose metabolism?

18. How does the genome of eukaryotes compare with that of prokaryotes?

19. Are operons found in eukaryotes?

20. Each eukaryotic cell contains a ___________________ set of genes, but only some genes

are ______________________ at a given time.

21. What controls much of the gene expression in eukaryotes?

22. What is euchromatin?

23. Some sections of chromatin always remain coiled preventing what process?

24. Name & define the 2 kinds of segments found behind the promoter in eukaryotes.

25. Where do the processes of transcription & translation take place in prokaryotes?

26. Where do these processes take place in eukaryotes?

27. Are introns and/or exons transcribed?

28. What is pre-mRNA and how is mRNA formed from this?

 

Section 11-2     Gene Expression and Development

 

29. Multicellular, sexually reproducing organisms begin life as a _____________________with all cells containing the same _______________________.

30. Genes may be turned ______________ and _____________as various ___________________ are needed by the cells.

31. What is cell differentiation?

32. Define morphogenesis.

33. What genes determine what anatomical structures an organism will develop during morphogenesis?

34. What is a tumor and what are the 2 main types?

35. Define benign tumor.

36. Are benign tumors dangerous? Explain.

37. What treatment do doctors use with benign tumors?

38. Define malignant tumor.

39. Malignant tumors are commonly known as ____________________________.

40. What is metastasis & what happens to the body when this occurs?

41. How are malignant tumors categorized?

42. Name & describe 4 types of malignant tumors.

43. Lung cancer & breast cancer are what type of tumors?

44. When do normal cells stop dividing? Do cancer cells respond the same way? Explain.

45. What trait of cancer cells facilitates the spread of cancer cells in the body?

46. What is a carcinogen & give 5 examples?

47. What causes most lung cancer?

48. What is the effect of mutagens on cells?

49. What are oncogenes?

50. Certain ____________________ can cause cancer in plants & animals.

BACK

 

Graph Examples

Examples of Graphs

LINE GRAPHS

Line Graph title

A line graph is most useful in displaying data or information that changes continuously over time. The example below shows the changes in the temperature over a week in January. Notice that the title of the graph is “Average Daily Temperature for January 1-7 in degrees Fahrenheit”.

To the left is a table that shows the date in one column and the corresponding temperature in the second column. The line graph on the right shows the degrees of temperature going up the vertical axis (up and down numbers on the left of the graph) and the days of the week on the horizontal axis (going sideways from left to right). The points for the temperature for each day are connected by a line – thus the graph is a line graph.

Average Daily Temperature for January 1-7 in Degrees Fahrenheit

Date
Temperature
1 10
2 25
3 30
4 42
5 23
6 25
7 40
Line Graoh of Average Temperatures

 

Bar Graph Animated title

BAR GRAPHS

Bar graphs are an excellent way to show results that are one time, that aren’t continuous – especially samplings such as surveys, inventories, etc. Below is a typical survey asking students about their favorite after school activity. Notice that in this graph each column is labeled – it is also possible to label the category to the left of the bar. In this case, the numbers for each category are across the bottom of the chart.

A bar chart is marked off with a series of lines called grid lines. These lines typically mark off a numerical point in the series of numbers on the axis or line. In this case, each grid line going up and down marks a multiple of 20 as the graph is divided.  More gridlines can make it easier to be exact with the amounts being shown on the bar graph, but too many can make it confusing.  Notice that for data that does not fall evenly on a multiple of 20, the bar is in between two grid lines.  Bar graphs are useful to get an overall idea of trends in responses – which categories get many versus few responses.

Favorite Student After School Activity

Activity Number
Visit W/Friends 175
Talk on Phone 168
Play Sports 120
Earn Money 120
Use Computers 65
Bar Graph

Circle Pie Graph Title

CIRCLE/PIE GRAPHS

Circle or pie graphs are particularly good illustrations when considering how many parts of a whole are inception. In the table below both the number of hours in a whole day devoted to certain activities is listed as well as the percent of time for each of these activities. The pie chart is then divided very much as a baker’s pie would be into slices that represent the proportional amounts of time spent on each activity.

To the right of the pie chart is a legend that tells which color stands for which category. In addition, the percents are also near the pie slice that stands for that particular amount of time spent.

Percent of Hours of a Day Spent on Activities

ACTIVITY HOURS PERCENT OF DAY
Sleep 6 25
School 6 25
Job 4 17
Entertainment 4 17
Meals 2 8
Homework 2 8

 

 

Pie Graph of Day's Activities

 

Genetic Notes Bi

 

Mendelian Genetics 

 

 

Mendel 1862 Mendel 1868 Mendel 1880
1862 1868 1880

 

Genetic Terminology:

  • Trait – any characteristic that can be passed from parent to offspring
  • Heredity – passing of traits from parent to offspring
  • Genetics – study of heredity
  • Alleles – two forms of a gene (dominant & recessive)
  • Dominant – stronger of two genes expressed in the hybrid; represented by a capital letter (R)
  • Recessive – gene that shows up less often in a cross; represented by a lower case letter (r)
  • Genotype – gene combination for a trait (e.g. RR, Rr, rr)
  • Phenotype – the physical feature resulting from a genotype (e.g. tall, short)
  • Homozygous genotype – gene combination involving 2 dominant or 2 recessive genes (e.g. RR or Rr); also called pure 
  • Heterozygous genotype – gene combination of one dominant & one recessive allele    (e.g. Rr); also called hybrid
  • Monohybrid cross – cross involving a single trait
  • Dihybrid cross – cross involving two traits
  • Punnett Square – used to solve genetics problems

Blending Concept of Inheritance:

  • Accepted before Mendel’s experiments
  • Theory stated that offspring would have traits intermediate between those of its parents such as red & white flowers producing pink
  • The appearance of red or white flowers again was consider instability in genetic material
  • Blending theory was of no help to Charles Darwin’s theory of evolution 
  • Blending theory did not account for variation and could not explain species diversity
  • Particulate theory of Inheritance, proposed by Mendel, accounted for variation in a population generation after generation
  • Mendel’s work was unrecognized until 1900

Gregor Mendel:

  • Austrian monk
  • Studied science & math at the University of Vienna
  • Formulated the laws of heredity in the early 1860’s
  • Did a statistical study of  traits in garden peas over an eight year period

 

drawing of a flower cross-section showing both male and female sexual structures

 

Why peas, Pisum sativum?

  • Can be grown in a small area
  • Produce lots of offspring
  • Produce pure plants when allowed to self-pollinate several generations
  • Can be artificially cross-pollinate

Picture of Pisum sativum
GARDEN PEA

Mendel’s Experiments:

  • Mendel studied simple traits from 22 varieties of  pea plants (seed color & shape, pod color & shape, etc.)
  • Mendel traced the inheritance of individual traits & kept careful records of numbers of offspring
  • He used his math principles of probability to interpret results
  • Mendel studied pea traits, each of which had a dominant & a recessive form (alleles)
  • The dominant (shows up most often) gene or allele is represented with a capital letter, & the recessive gene with a lower case of that same letter (e.g. B, b)
  • Mendel’s traits included:

         a. Seed shape —  Round (R) or Wrinkled (r)
            b. Seed Color —- Yellow (Y) or  Green (y)
            c. Pod Shape — Smooth (S) or wrinkled (s)
            d. Pod Color —  Green (G) or Yellow (g)
            e. Seed Coat Color —  Gray (G) or White (g)
            f. Flower position — Axial (A) or Terminal (a)
            g. Plant Height — Tall (T) or Short (t)
            h. Flower color — Purple (P) or white (p)


  •  Mendel produced pure strains by allowing the plants to self-pollinate for several generations
  • These strains were called the Parental generation or P1 strain
  • Mendel cross-pollinated two strains and tracked each trait through two
    generations (e.g. TT  x  tt )

     

                  Trait – plant height

                  Alleles – T tall, t short

    P1 cross    TT  x  tt

    		 genotype      —    Tt
    t t phenotype    —    Tall
    T Tt Tt genotypic ratio –all alike
    T Tt Tt phenotypic ratio- all alike

     

 

  • The offspring of this cross were all hybrids showing only the dominant trait & were called the First Filial or F1 generation
  • Mendel then crossed two of his F1 plants and tracked their traits; known as an F1 cross

 

              Trait – plant height

              Alleles – T tall, t short

F1 cross    Tt  x  Tt

 genotype      —    TT, Tt, tt
T t phenotype    —    Tall & short
T TT Tt genotypic ratio —1:2:1
t Tt tt phenotypic ratio- 3:1

 

 

  • When 2 hybrids were crossed, 75% (3/4) of the offspring showed the dominant trait & 25% (1/4) showed the recessive trait; always a 3:1 ratio
  • The offspring of this cross were called the F2 generation
  • Mendel then crossed a pure & a hybrid from his F2 generation; known as an F2 or test cross

 

Trait   –  Plant Height
Alleles – T  tall, t  short

F2 cross       TT  x Tt

F2 cross       tt  x Tt
T t T t
T TT Tt t Tt tt
T TT Tt t Tt tt
          genotype – TT, Tt           genotype – tt, Tt
          phenotype  –  Tall           phenotype  –  Tall & short
          genotypic ratio  – 1:1           genotypic ratio  – 1:1
          phenotypic ratio – all alike           phenotypic ratio – 1:1

 

  • 50% (1/2) of the offspring in a test cross showed the same genotype of one parent & the other 50% showed the genotype of the other parent; always a 1:1 ratio

Problems: Work the P1, F1, and both F2 crosses for all of the other pea plant traits & be sure to include genotypes, phenotypes, genotypic & phenotypic ratios.

  • Mendel also crossed plants that differed in two characteristics (Dihybrid Crosses)
    such as seed shape & seed color
  • In the P1 cross, RRYY  x  rryy, all of the F1 offspring showed only the dominant form for both traits; all hybrids, RrYy

 

Traits:      Seed Shape & Seed Color

Alleles:     R round                Y yellow
r wrinkled             y green

 P1 Cross:     RRYY          x     r r yy  

      

ry Genotype:      RrYy
RY RrYy
 Phenotype:      Round yellow seed
Genotypic ratio:      All alike
Phenotypic ratio:      All Alike

 

  • When Mendel crossed 2 hybrid plants (F1 cross), he got the following results

 

 

Traits:       Seed Shape & Seed Color

Alleles:     R round                Y yellow
r wrinkled             y green
     F1 Cross:     RrYy           x     RrYy                   
RY Ry rY ry
RY
RRYY
RRYy
RrYY
RrYy
Ry
RRYy
RRyy
RrYy
Rryy
rY
RrYY
RrYy
r rYY
r rYy
ry
RrYy
Rryy
r rYy
r ryy

 

 

 

Genotypes Genotypic Ratios Phenotypes Phenotypic Ratios
RRYY 1 Round yellow seed
 9
RRYy 2
RrYY 2
RrYy 4
RRyy 1 Round green seed
 3
Rryy 2
r rYY 1 Wrinkled yellow seed
 3
r rYy 2
r ryy 1 Wrinkled green seed
 1

 

Problems: Choose two other pea plant traits and work the P1 and F1 dihybrid crosses. Be sure to show the trait, alleles, genotypes, phenotypes, and all ratios. 

Results of Mendel’s Experiments:

  • Inheritable factors or genes are responsible for all heritable characteristics
  • Phenotype is based on Genotype
  • Each trait is based on two genes, one from the mother and the other from the father
  • True-breeding individuals are homozygous ( both alleles) are the same
  • Law of Dominance states that when different alleles for a characteristic are inherited (heterozygous), the trait of only one (the dominant one) will be expressed. The recessive trait’s phenotype only appears in true-breeding (homozygous) individuals

 

Trait: Pod Color
Genotypes: Phenotype:
GG Green Pod
Gg Green Pod
gg Yellow Pod

 

  • Law of Segregation states that each genetic trait is produced by a pair of alleles which separate (segregate) during reproduction

 

Rr
R r

 

  • Law of Independent Assortment states that each factor (gene) is distributed (assorted) randomly and independently of one another in the formation of gametes

 

RrYy
RY Ry rY ry

 

 

Other Patterns of Inheritance:

  • Incomplete dominance occurs in the heterozygous or hybrid genotype where the 2 alleles blend to give a different phenotype
  • Flower color in snapdragons shows incomplete dominance whenever a red flower is crossed with a white flower to produce pink flowers

  • In some populations, multiple alleles (3 or more) may determine a trait such as in ABO Blood type
  • Alleles A & B are dominant, while O is recessive

 

Genotype Phenotype
IOIO Type O
IAIO Type A
IAIA Type A
IBIO Type B
IBIB Type B
IAIB Type AB

 

  • Polygenic inheritance occurs whenever many variations in the resulting phenotypes such as in hair, skin, & eye color
  • The expression of a gene is also influenced by environmental factors (example: seasonal change in fur color)