Questions tagged [homework]

This tag indicates that the question is likely based on a home assignment in biology-related university or high school courses or is about an elementary concept that may seem trivial to biology professionals. Please see the homework policy on meta before asking homework questions.

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108 views

What happens between two nodes in an evolutionary tree?

Hey guys can you help me with this one!? What happens between two nodes (in an evolutionary tree) or a between a node and a tip? A) at least one character changes B) all organisms die C) ...
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1answer
638 views

Calculating PCR Cycles

I have a problem understanding a PCR exercise, it says to calculate the number of cycles to get 1µg of the DNA fragment, starting from 10ng and then from 500ng, I know about 2^n, and the exercise even ...
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1answer
81 views

Protein electrophoresis

Three proteins A, B and C of equal molecular weight are being investigated in a study. They contain six, four and four cysteine residues respectively. Only Proteins A and B were treated with β-...
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3answers
560 views

Why does photosynthesis occur even in blue light when the photocentres are activated in red light

From Engelmann's experiment Engelmann used this device to illuminate a strand of Cladophora (not Spirogyra) with light from the visible spectrum, exposing different sections to different ...
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0answers
49 views

Monohybrid Recombinant Frequency? (three point Gene Linkage)

I am curious to know if it is completely impossible calculate recombinant frequency for monohybrids ( three point link, gene map etc.) Here is an example: Marker 1 xx= 25 xy=100 yy= 20 Marker 2 ...
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1answer
75 views

When in the cell cycle is the number of chromosomes normally reduced?

Page 96 of the Study Guide for Campbell Biology, 11th Edition has the following question: A reduction in the number of chromosomes per cell occurs a. During meiosis I b. During meiosis ...
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1answer
39 views

How are chromosomes counted at the end of mitosis in a plant cell?

Page 89 of the Study Guide for Campbell Biology, 11th Edition has the following question: A plant cell has 12 chromosomes at the end of mitosis. How many chromosomes would it have in the G2 ...
3
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1answer
824 views

Is pith a ground tissue with no specialized function?

Here is a question from the book My Max Score SAT Biology E/M Subject Test (where the SAT is the exam taken by American high school students): Ground tissue with no specialized function A. Xylem ...
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1answer
47 views

How many birds in this population would be expected to have either red or white feathers?

Question: The red and white feather pattern of a bird is determined by a gene that has two alleles, band R and W,which show codominance. Some birds have completely red feathers (RR),some parrots ...
3
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1answer
47 views

How is ligand binding modeled?

I have the following exercise to solve: To be honest, for both parts, my only idea so far would be to divide the rate expression by the sphere area and multiply by the new available areas (that of a ...
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0answers
43 views

Net electrical load of a peptide

I have to determine the electrical charge of the next peptide chain: C - E - H - P I know that this page is not there to raise doubts about this style, but I have looked for resources on the ...
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1answer
2k views

Why does this genetic pedigree show an autosomal dominant allele at one generation but not another?

Questions 186-188 of the GRE Biology Practice Test are prefaced with this genetic pedigree: Questions 186-188 refer to the following pedigree for the inheritance of a very rare human disease over ...
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0answers
61 views

What change would you expect in phospholipid orientation of the membrane if the enviornment were mostly heptane?

The external and internal environment of the cell is basically water, thus phospholipids organize themselves the way they do (bilayer). If the environment were to magically become mostly heptane, how ...
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1answer
306 views

Why doesn't oligodendrocyte produce neurilemma

I was searching literature related to neurilemma and oligodendrocyte and came across these lines from WP (Neurilemma) Oligodendrocytes do not have neurilemma because excess cytoplasm is directed ...
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1answer
70 views

Is α-keratin a fully functional protein?

Is α-keratin before it coils with another polypeptide, makes chains, and build intermediate filaments a fully functional protein? I mean, is the single monomer of α-keratin a protein or does it have ...
2
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1answer
448 views

Why do proteins targeted for chloroplasts require two signal peptides?

Question #11 of the GRE Biology Practice Test says that proteins targeted for chloroplasts require two signal peptides: Targeting of a newly synthesized protein is most likely to require two ...
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1answer
873 views

How to find the amino acid that is bound to a tRNA with the anticodon? [closed]

What amino acid is bound to a tRNA with the following anticodon: $5^{\prime}$ A U G $3^{\prime}$ The answer is Histidine. What amino acid is attached to the tRNA with the ...
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2answers
138 views

How to find the amino acid in the DNA protein

3' A T A G T A C C G C A T G T A C G G G C G A G A C A T T C G A G C A T T C A T 5' This a Template DNA. How to find the number of amino acids amino acids ...
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3answers
97 views

Biological validation of computationally determined gene-gene interaction

How can a computationally determined three-way gene interaction be biologically validated? What kind of assays or tests must be performed using cell/tissue-based and/or mouse models to prove that the ...
3
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3answers
89 views

Is it possible to prove that a hand sanitizer can kill 100% of a person's germs?

We have a project for Economics, and we need to advertise something that consumers will be willing to buy. My group thought of "improved" hand sanitizer. So, instead of it killing 99.9% germs, we ...
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0answers
22 views

Is this tree poisonous?

I touched this tree on my visit to South Africa and a huge rash developed on my body,please help,what is the name of this
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1answer
71 views

If an antiserum was raised in a buffalo by injecting it with monkey red blood cells, what would be the full name for this antiserum?

Im confused, i've attempted this & what i got is buffalo anti-monkey red blood cell antiserum. I'm not sure if this answer is right
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1answer
131 views

Is this answer about the limiting factor correct?

The graph shows the result of adding both phosphorus and nitrogen to different algae populations. I have a hard time figuring out why the correct answer is C, I thought that groups 4 and 5 would have ...
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1answer
82 views

Advanced Higher Biology 2017 - EPT Index

I was recently completing a biology past paper the Scottish SQA 2017 Advanced Higher Biology Qualifications. The question is as follows: To solve this, I did: EPT Index = 100*(striped stonefly + net ...
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0answers
88 views

eosinophil question

Which of the following statement(s) is/are incorrect? A. All cells of the immune system originate in the Bone Marrow B. Lymphoid progenitor cells originate from a pluripotent stem cell C. B cells ...
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1answer
36 views

Sex determination in Drosphila [closed]

Ive been taught that its based on genic balancing. But I recently saw this question that has caused me some doubt. I thought it would be the 1st option but unfortunately they said it to be the 3rd. ...
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1answer
59 views

What is the type of conservation in which seed banks are an example? [closed]

Firstly I think this question is quite ambiguous (I did not come up with it) so sorry. I have only come across 4 'types' of conservation: environmental, animal, marine, and human conservation. I am ...
2
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1answer
380 views

How would one go about isolating a specific mRNA out of a pool of others? [closed]

I'm writing an essay about DNA recombinant techniques where the question asks to outline all the steps to arrive at having a colony of bacteria expressing a gene of interest.The question makes you ...
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2answers
45 views

Number of different clones of B lymphocytes

My professor told us that there are about a million different B cells based on their surface receptor. I have read that we have about 30000 genes in all. Since receptors are proteins how do these ...
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1answer
52 views

Prove that the worms are unicellular

In Biology class our teacher divided the class in two groups. Our group(i'm in) has to prove that the worms are unicellular(although it is not true). The other group has to prove that we are wrong. ...
2
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0answers
57 views

Sucrose inhibit onion root mitosis? Why?

I am doing an experiment about onion root growing. I had put an onion in different solutions of $C_{11} H_{22} O_1$ in H2O —with the root touching the water—: 0,1M; 0,2M; 0,3M; 0,4M; 0,5M. The ...
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1answer
58 views

Understanding Genetic Dynamics of Specific Problem

The following questions comes from International Biology Olympiad 2014, theoretical part B. It states: Earlier research suggested that the red flower pigment of plant species was the result of a ...
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1answer
137 views

law of independent assortment [closed]

Self fetilization of F1 dihybrids, following independent assortment of alleles result in: ...
3
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1answer
663 views

Which statement is incorrect for Rubisco?

My question is this: Which of the following is NOT correct for rubisco? a. It is the most abundant enzyme b. It catalyzes two different reactions c. It is involved in photorespiration d. It is not ...
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2answers
5k views

Genes & Map Units

Two genes of a flower, one controlling blue (B) versus white (b) petals and the other controlling round (R) versus oval (r) stamens, are linked and are 10 map units apart. You cross a homozygous blue ...
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2answers
2k views

Why aren't 'exons' named 'introns'?

Why are introns called 'introns' when they are the actual ones who are getting spliced out from the pre-mRNA. Shouldn't exons be named introns as they are the ones that are 'in' and are not 'exiting'? ...
0
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1answer
216 views

How do you find probabilites of carrying an X linked recessive disease in a blank pedigree given only one phenotype?

In the above pedigree, the black square indicates the male affected with Hemophilia which is a X-linked recessive trait. What is the probability that the proposed child, which is a male (indicated as ?...
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2answers
159 views

Is the xylem like a tissue paper?

I am a 5th grader learning about the plant transport mechanics and I learnt that the xylem is made up of dead cells.So if water travels up the xylem and water travels only 1 way, is it like how water ...
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2answers
876 views

Intermediate of Krebs cycle that can form Chlorophyll?

This was a question in a test in my school today. Q) Which intermediate of Krebs cycle further can form chlorophyll? A) Oxaloacetic acid B) Citric acid C) Succinyl CoA D) Fumarate Given answer was ...
7
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1answer
281 views

Why does the olive tree produce a bitter tasting fruit?

What is the survival value for the olive tree to produce a bitter tasting fruit, even when it is ripened? I realize some fruits and berries are species specific, i.e., meant for specific animals to ...
1
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1answer
119 views

Mathematical model about the relationship between two animal species

I'd like to relate a mathematical model with two animal species. This is the model: $$ \begin{split} \frac{dN}{dt} & =rN-\frac{rN(N+M)}{k} \\ \frac{dM}{dt} & =r'M-\frac{r'M(N+M)}{k'} \end{...
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0answers
60 views

Homework: Diffrentiate between 2 toads

How to differentiate between 2 toads one of them result of artificial parthenogenesis and the other from renucleation? I answered that the toad resulting from artificial parthenogensis is identical ...
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1answer
103 views

Homework - Genetics linkage problem

A farmer purchases f1 hybrid seeds. These seeds contain four heterozygous loci that give a significant increase in crop yield when compared to either homozygote. Two of these loci are on the same ...
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2answers
8k views

Unsure about definition of “n” and “C” values in mitosis

I am preparing for a Biology exam and I'm reviewing the "n" and "C" notation used in mitosis. My professor said that when the cell replicates its DNA in S phase of mitosis, we get twice the "amount" (...
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4answers
272 views

Best fundamental books? [duplicate]

I’m looking for internationally applauded textbooks on fundamental biology. Books that are a must for a pre-medicine student/high school advanced. Currently, I study Biology by Neil Campbell, Jane ...
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1answer
370 views

Which function do nicotinic receptors have in the periphery?

I came across this question today, it says: Nicotinic receptors stimulation is directly responsible for ….... I should fill the spaces by one of the following choices: Increasing the excitability ...
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1answer
1k views

R nought calculation ( SIR model)

1 person gets bitten by 9vectors /night, the vector transmits the pathogen to 0.035 new hosts. Duration of infection: 9.5 months.What is R0? I am struggling with this question for ages as I would ...
3
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1answer
835 views

Question about different gametes that can be produced

I have a question from a past exam that asks the following: "For the organism of genotype AABbCcDDEe (homozygous for 2 genes, heterozygous for 3 genes), how many different types of gametes will be ...
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1answer
94 views

Serial dilutions

A student wants to make serial dilution of a sample. She starts with a 1mg/ml sample and 10 tubes, (labelled 1-10) each containing 2 ml buffer. The student puts 1ml of sample solution into tube 1 ...
1
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1answer
462 views

Questions about apoptosis [closed]

Is apoptosis a part of cell division? Can apoptosis occur if DNA is damaged beyond repair?

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