Online Science Education

Test Cross help.

ph0bolus — Sat, 28 Jun 2008 16:21:02 GMT

My professor once again gave me problems to work out where in which I have no idea on how to start out on them...Can someone lead me in the right direction please?

1. A three-point testcross was made in corn. The results and a partial recombination analysis are shown in the following display, which is typical of three-point testcrosses (p = purple leaves, + = green; v = virus- resistant seedlings, + = sensitive; b = brown midriff to seed, + = plain).

a. Determine which genes ...

Are Antibiotics too dangerous to be used?

icedoxx — Sun, 29 Jun 2008 04:51:16 GMT

Hi, Im doing an essay on Antibiotics. The essay question is 'Are Antibiotics too dangerous to be used?'

There are 3 sections to the essay:

Biological Relevance

Impact of the issue

Management

Ive started my essay and have talked about the types of antibiotics:

1. Bactericidals

I have said how they work. They inhibit peptidoglycan synthesis and some inhibit protien synethsis. i have written about how they do this ect.

2. Bacteriostatics

I am stuck on how Bacteriostatic ...

Terminology game!

Alla — Fri, 27 Jun 2008 00:21:35 GMT

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Cats belong to which family?

Are Antibiotics and Vaccines too dangerous to be used?

icedoxx — Sun, 29 Jun 2008 08:23:04 GMT

Stage 2 Biology - Summative Human Awareness Essay - By Druva Mitra

Are Antibiotics and Vaccines too dangerous to be used?

Antibiotics are drugs used to treat infections caused by bacteria. The human body houses many types of bacteria that live peacefully and even some that help the body to function. Some types of bacteria are dangerous and affect the body�s ability to function normally. There are many well known infections that are caused by bacteria; some include tuberculosis, salmonella, ...

Terminology game!

Alla — Fri, 27 Jun 2008 00:42:57 GMT

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Two sulfur containing amino acids are __________ and __________.

Terminology game!

Alla — Fri, 27 Jun 2008 00:37:09 GMT

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What is the name of the smallest alkane?

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Alla — Fri, 27 Jun 2008 00:33:29 GMT

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What is the name of the smallest atom?

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Alla — Fri, 27 Jun 2008 00:28:45 GMT

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Which virus causes chickenpox?

Terminology game!

Alla — Fri, 27 Jun 2008 00:25:47 GMT

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What is the name of red blood cells?

Terminology game!

Alla — Fri, 27 Jun 2008 00:24:41 GMT

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What type of muscle tissue is found in the heart?

Terminology game!

Alla — Fri, 27 Jun 2008 00:19:23 GMT

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Totipotent cells can be located in what tissues?

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Alla — Fri, 27 Jun 2008 00:15:48 GMT

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What is tomato? Is it a vegetable, a fruit or a berry?

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Alla — Fri, 27 Jun 2008 00:11:47 GMT

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What is the general name of the pathways that relay information from hormones to nucleus?

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Alla — Fri, 27 Jun 2008 00:09:41 GMT

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What is the full name of the natural genetic engineer of plants?

Terminology game!

Alla — Fri, 27 Jun 2008 00:07:05 GMT

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Gene replacement can be achieved by which method?

Terminology game!

Alla — Fri, 27 Jun 2008 00:03:41 GMT

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If all progeny genotypes are Aa, what where genotype(s) of parents? Who was homozygous, heterozygous, or hemizygous?

Terminology game!

Alla — Fri, 27 Jun 2008 00:00:48 GMT

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What amino acid is encoded by start codon?

Terminology game!

Alla — Thu, 26 Jun 2008 23:57:06 GMT

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Hospital acquired infections are called _________.

Terminology game!

Alla — Thu, 26 Jun 2008 23:54:57 GMT

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What is the common test to differentiate Staph from Strep? (include test results!)

Terminology game!

Alla — Thu, 26 Jun 2008 23:50:20 GMT

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DNA can be found in which organelles? (There are 3 of them!)

Question about mRNA

Alla — Thu, 26 Jun 2008 23:37:11 GMT

vicereine wrote:The piece of genetic information removed from an mRNA strand after translation is called a(n)_________.

a) codon

b) anti-codon

c) termination codon

d) exon

e) intron

ok if it said transcription I know it would be the introns are removed, but what is removed after translation? Is it the termination codon (since all components come apart at the end)? Or is this a typo? I ask because I've found some mistakes in my math lessonbook (I'm doing correspondence). It takes ...

Mendelian Genetic problems

Alla — Thu, 12 Jun 2008 22:34:30 GMT

Ph0BoLuS wrote:My instructor gave me some problems to help study for the quiz on Monday, but i have no idea how to go about solving them..

1) In martians, Gene 1 is determining eye shape (A-star eyes; a- square eyes) and Gene 2 is coding for presence or absence of tail hairs (B-hairy tail; b-smooth tail). True- breed star eyed individual with smooth tail marries another true-breed square-eyed individual with hairy tail and all of their childred have star eyes and hairy tailes. If mendelian ...

Tricky Question

georgina_009 — Tue, 27 May 2008 05:20:36 GMT

Hi,

I have this qn that dosent seem to give me enough info to work it out (though I suppose it does and I just cant do it)

-94,075 babies born over a period of time. Then were diagnosed as achondroplastic dwarfs, an autosomal dominant trait showing full penetrance. Only two dwarfs had a dwarf parent. What is the mutation frequency in the gametes? Assume all mutations occured in the gametes.

Im not sure what to do.

Thanks for any help

Sickle cell anemia

georgina_009 — Sun, 18 May 2008 08:14:11 GMT

I've done some answers to this so could you check them and help with the last one?

Sickle cell anemia is an example of how fitness depends on environmental cond. In malaria prone places Hb^A Hb^S have advantage over normal. But Hb^S Hb^S usually die.

The relative fitness (w) of them in Nigeria:

wild type - 0.87 Hb^A Hb^S - 1.0 Hb^S Hb^S 0.05

a) What is the relationship between w and selection co efficient?

b) What is the selection coefficient (s) for each genotype?

c) ...

Hardy weinberg equilibrium

georgina_009 — Mon, 12 May 2008 05:30:01 GMT

Thanks for your help with restriction mapping i eventually managed to figure out what i did wrong in that last one and used how you did the easier one to map it.

I just wanted know if you could tell me how to do/ tell me if i'm right for these qns:

There are only two alleles for a particular gene in a pop. The frequency of heterozygotes is 20% Assuming hardy weinberg equilibrium calculate the allelic frequencies in this pop.

Haemophilia A is a rare reccesive sex linked trait. ...

Frequencies

georgina_009 — Sun, 18 May 2008 07:38:14 GMT

Hi Alla,

I'm sure you're sick of helping me by now but what do you make of this qn?

-Dunkers are a secluded group originally from rhineland germany before settling in pennsylvania USA during 18th century. Since then they have remained secluded in marriages and customs. The frequency of ABO blood types found in the Dunkers compared to the surrounding American pop and present day rhinelanders is:

Group - no. people tested-Blood frequencies: A......AB......B...........O

Dunkers...228...........................................0.61...0.02....0.04....0.33

Rhinelanders....3036..................................0.45....0.05.....0.10.....0.40

eastern ...

Plasmids restriction enzyme question

georgina_009 — Wed, 07 May 2008 01:52:59 GMT

Sorry to overload you with qns but this is another thing I cant understand:

Plasmid pUNE92 has been digested with BamHI and HindIII restriction enzymes in various combos. the following DNA fragments sizes were seen:

BamHI - 4.0 + 2.0 kb

HindIII- 6.0 kb

BamHI + HindIII - 3.0, 2.0 1.0 kb

a. What is size of the plasmid? my answer - 6kb

b. How many sites are cut by each enzyme? - my answer - Bam - 2, Hin - 1, Bam Hind - 3?

c. This part Im not sure how to do - Draw a restriction ...

Lac operon

georgina_009 — Wed, 07 May 2008 04:29:21 GMT

Sorry again for the millions of qns but Im doing quite badly in this subject so I need loads of help!

Could you just check my answer for this qn?

A lacI mutation leads to repressor not able to bind to operator at 42 degrees. At 37 deg. the lacI repressor is same as wild type. Do you expect to see B-galactosidase activity under these conditions?:

a) LacI - 37 deg - lactose absent - activity - (my answer) no

b)LacI - 37deg - lac present - activity yes

C) lacI - 42 deg. - lac absent ...

Complementation test

georgina_009 — Mon, 05 May 2008 05:32:19 GMT

I have a qn that says:

5 mutant strains of fungus which couldn't synthesise amino acid arginine were isolated. Each has a single mutation. Complementation tests using the 5 strains were carried out and the results show below (+ means complementation and - means no growth) Table - http://i30.tinypic.com/mll06o.jpg

then it asks - what is the min. no. of diff genes involved in the biosynthesis of argenine?

Show which strains have mutations in which genes.

SO: does this mean two ...

Biology from Penn Foster

Alla — Sat, 19 Apr 2008 17:55:43 GMT

emmaposse wrote:

This is Biology......

1. When you exercise vigorously, glycogen is broken down in muscle cells, proving energy to

A. the entire body B. the heart and muscle cells

C. the parts being exercised D. muscle cells

2. During moderate exercise, a body gets most of its energy from

A. carbohydrates B. cellulose

C. glucose D. triglycerides

3. A renal tubule passes most of the fluids it processes into

A. the urinary bladder B. the bloodstream

C. a glomerulus ...

Screening effect

wilson — Sat, 12 Apr 2008 06:58:07 GMT

My Chemistry teacher told me that screening effect is the ability of the atom to prevent the valence electrons from being pulled towards the nucleus. The screening effect depends only on the number of electron orbits inside the valence shell. For example, the atoms across Period 3 have 3 shells occupied by electrons. So, the screening effect remains unchanged.

But I thought that when going across Period 3 from left to right, the number of electrons increases and so does the electrostatic ...

Protein Concentration and Cytotoxicity

Alla — Sat, 29 Mar 2008 03:31:53 GMT

The article you are working with is the one I read. So these are my findings and conclusions from this paper (for figures refer to paper).

http://www.landesbioscience.com/journals/cc/article/yamadaCC3-9.pdf

Rusticyanin (Rus):

1. Effect on p53:

A. Translocation of p53 from cytoplasm to mitochondria that leads to ROS production (figure 3D)

B. No effect on nuclear p53 fraction (figure 3D)

C. Overall slight reduction of cellular p53 (particularly cytosol and mitochondria) ...

Rat touch prep slides (Spleen, Mesentery, Testes)

RatoScope — Wed, 26 Mar 2008 02:16:41 GMT

Male Rat "Pete", 27 months of age.

Signs of illness: weight loss, respiratory illness (chronic)

Necropsy: Mesentery mass, extreme splenamegaly with (lesioned and bulbous in areas), enlarged lung lobes (tissue hardened in some areas and spongy in others).

I will be sending the tissue out for histology. In the meantime, I made slides of the diseased organs. I have no background in cytology, so I would love some help in learning to identify what I am seeing. It is amazing to ...

Drosophila Genetics problem

georgina_009 — Mon, 17 Mar 2008 23:36:51 GMT

Hi,

I have another question that I need help on - I'm hopeless at making sense of these questions:

Normal wild eye colour in Drosophila is dark red

White eyed mutation (w) is on the X chromosome

purple eye colour (pr) is autosomal

The wild type alleles for both genes (w+ pr+) are dominant

Mutations in the white gene exhibit recessive epistasis with respect to all other Drosophila eye colour mutations.

qn -

If a white eyed true breeding female is crossed with a purple eyed ...

Dominant vs. Recessive

Alla — Wed, 19 Mar 2008 20:23:49 GMT

Paragonidae wrote:so that brings me back to the beginning, how is it that one allele is expressed over the other while if it the recessive one on its own (with its homologous) they are expressed, is it a question of quantitative effect where the dominant is expressed stronger and the recessive expression is insignificant in comparison and when there are two of them they make enough product to be expressed phenotipicaly. sorry for repeating this but it is really hard for me to understand. maybe ...

Dihybrid Cross

Alla — Tue, 18 Mar 2008 18:42:12 GMT

VPer wrote:I'm struggling with this problem:

A female fly with alleles S and C is mated with a wild-type male fly. F1 progeny is found to be 50% wild-type and 50% C (phenotypes). Draw the Punnet square for this cross.

I would also need help in determining the punnet square for the F2 progeny.

Given:

Female has alleles for C and S, and, therefore, presumed to display those phenotypes.

Male is wild type, and, therefore, presumed to be homozygous for WT alleles of

C and S phenotypes.

F1 ...

A few questions related to RNA

georgina_009 — Mon, 17 Mar 2008 23:47:18 GMT

1.

what the effect on the size of the protein translated from mRNA would be if the shine dalgarno sequence was replaced with CTTTCCCTT. Would it be decreased or no protein produced?

2.

How do I find the promoter sequence in an e.coli strand on DNA? I found an area of TTGACA but it is nucleotides 86-91 and the start codon starts at nucleotide 226. Then what i think is the pribnow box is CATAAT which is nucleotides 198-203. So i guess what I really what to know is: is the TTGACA got anything ...

True Breeding Drosophila

Alla — Fri, 14 Mar 2008 03:06:20 GMT

Data:

_______Male - Female

WT_____42 - 74

CR _____12 -26

P_______32 -0

P, CR___14 - 0

First, examine relationship to determine if 2 mutations are linked. Since CR (curly) and P (purple) can occur independently, they are not on the same chromosome.

Second, CR occurs equally in males and females 26:26 (or 1:1) and, therefore, is not sex linked. Now, examine the numbers of non-CR and CR, they are 148:52, which is approximately 3:1 of wt:mutant (for this particular trait). This ...

Genetic problem

Alla — Mon, 17 Mar 2008 18:50:27 GMT

georgina009 wrote:Can anyone help me with this question? I am very confused!

In corn-

coloured kernal - R

colurless - r

green plant colour - Y

yellow plant colour - y

The R and Y genes are linked. Two different plants (1 and 2) that were heterozygous for each trait - RrYy - were test crossed to plants that were homozygous for reccessive alleles. this info was gotton from that:

Coloured green -plant 1 145 plant 2- 18

colured yellow - 1-13 2-175

colourless green - ...

Hardy Weinberg question

Alla — Fri, 14 Mar 2008 18:54:32 GMT

First of all, your population is quite small and you are assuming that both parents are heterozygous (or is it given in your problem?). In this case, the expected phenotypic ratio of dominant: recessive is 3:1.

Your total number of individuals in this experiment is 34, so your

expected numbers would be 25.5 Brown: 8.5 Blue and

observed numbers are 24 Brown: 10 Blue

if you do a chi-square test with these numbers, you get:

--------BR-----BL

Obs____24____10

Exp____25.5__8.5

Dev ...

Affiliation

Draco — Thu, 28 Feb 2008 19:59:53 GMT

I was wondering if you would like to affiliate with my Geology forum Geo Center?

http://geo-center.heavenforum.com/index.htm

I will put up a link to this site on my portal page.

Thanks.

Geology Links

Admin — Thu, 28 Feb 2008 20:53:39 GMT

Geo-Center: http://geo-center.heavenforum.com/index.htm

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Online Science Education is looking for volunteer instructors and moderators. If you are thinking about career in Education this is a good opportunity to obtain experience for you. To become an instructor, you need to have at least a B.S./B.A. in the area which you wish to teach. Instructors have responsibility to check the website at least twice a week and answer any questions posted in the tutoring sections of their area of expertise. He or She is responsible for looking up information/details ...

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Welcome to Online Science Education!

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