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7
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3answers
15k views

Does Human Female Meiosis II occur after fertilization with sperm?

I am reading the answer and I am getting confused by the sentence: At the end of meiosis I females have two daughter cells and meiosis II only occurs if and when fertilization occurs by a sperm ...
2
votes
2answers
92 views

Calcium levels and nerve hyperexcitation

Why does lower blood calcium levels (or lower calcium levels in ECF) cause nervous hyperexcitaton? Why does it cause over stimulation of nerves and muscles and spasmic contractions of muscles? This is ...
1
vote
1answer
35 views

How to determine if this blood disorder is recessive or dominant?

This question is from "Concepts of Genetics," Klug & Cummings, 10e. "Thalassemia is an inherited anemic disorder in humans. Affected individuals exhibit either a minor anemia or a major anemia. ...
3
votes
3answers
65 views

True or false & fill in the blanks

A ribosome is where amino acids are linked together by peptide bonds. A virus is NOT considered prokaryotic because it does not have a membrane. The nucleotide ATP is one of the most used energy ...
3
votes
2answers
60 views

Assessing probability from a pedigree

This isn't exactly homework but I'd like to treat it as such. I'm asked to find the probability that both (III: 2) and (III: 3) are carriers given that (II: 7) and (III: 1) exhibited the recessive ...
0
votes
1answer
48 views

Hypothalamic breakdown and effect of temperature on membrane lipids

I'm in my last year of high school and doing a research assignment on thermoregulation. In the excellence level exemplar for the standard, a student made the statement: Once the body's internal ...
3
votes
1answer
44 views

spinal cord lesion and result in somatic sensation

Jimbo suffers a lesion to the entire right half of the spinal cord at the T6 level. A few weeks after his injury, his doctor tests his right and left legs for somatic sensation and tone. fill out her ...
1
vote
0answers
31 views

Is probability for double crossing over included in distance cM? [task]

We got this task: There are 3 genes (acb) on one chromosome (linked inheritance). Distance a-c = 12cM, a-b=16cM. Probability for double crossing-over (CO) is 0,6%. Find ratio of genotypes of ...
-1
votes
1answer
94 views

Can someone help me analyze this article?

I need to read this article — "Beyond the rainbow" by Marie-Claire Koschowitz et al., for an exam. Following are some questions for which I could not figure the answer out after reading. 1) Why ...
1
vote
1answer
54 views

What is meant by “genes involved in the stress response”?

I would like to know about the term stress response. For example "some genes of a species under study is involved in stress response". What does that mean? I got this as a part of my assignment ...
1
vote
1answer
28 views

Amphibian blood circulation

In an amphibian blood entering the right atrium shows higher levels of oxygenation than that in left atrium when : A.It is hyperactivated B.it is hibernating C.it is submerged D.it is in the ...
0
votes
1answer
28 views

PCR cycle problem [closed]

IF I began a PCR cycle with 5 copies of a particular DNA section, and copied the section by PCR, for 6 cycles, how many copies of the DNA (include the originals) would I have by the end of these ...
0
votes
1answer
23 views

Intro Bio question: dihybrid punnet square

Today we had our exam. There was a punnet square for two genes. and when I multiplied , for example, Ry × rY I wrote the answer as ...
1
vote
1answer
117 views

Energy flow in an ecosystem

What are the mistakes in here? The image below shows a part of the energy flow diagram in an ecosystem. 1. Part P of the biomass of the primary producers does not get consumed. Give a concrete ...
1
vote
1answer
475 views

Amino acid characteristics that determine their chemical properties?

What chemical aspect of amino acids results in their having different properties such that the chemical and physical properties of polypeptides vary with both amino acid content and amino acid order? ...
2
votes
1answer
54 views

Problem on number of amino acids that an alien can use

A new life form discovered on a distant planet has a genetic code consisting of five unique nucleotides and only one stop codon. If each codon has four bases,what is the maximum number of unique amino ...
2
votes
1answer
99 views

Mouse meta-globin mRNA problem

This is an mRNA strand of mouse meta-globin: 5'-ccccagauacggaauucgaau-3' A) Which small RNA (below) is most likely to regulate expression of meta-globin? ...
0
votes
2answers
32 views

T-cells Question

T-cells are important for efficient vaccination since they have: A. T-cell receptor (TCR) B. CD4+ C. CD8+ D. Memory My gut is telling me it's A since the TCR would recognize the antigens but I ...
2
votes
1answer
61 views

Simple Mendelian Genetics Question

here is my question: In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short? My ...
5
votes
1answer
73 views

Restriction Mapping - Homework question

I have trouble in solving this exercise. Exercise A circular plasmid of 10,000 base pairs (bp) is digested with two restriction enzymes,A and B, to produce a 3000 bp and a 2000 bp bands when ...
1
vote
0answers
14 views

Why do Sorghum Bicolor leaves roll up?

In A level Bio today we talked about abcesic acid as a stress hormone, and its ability to reduce osmotic potential around guard cells to close stomata. My question is, is abscesic acid in sorghum ...
1
vote
1answer
82 views

Interpretation of graph from evolutionary biology

I am studying evolutionary biology, and been presented with this graph: I am having some difficulties understand its meaning. For a start, why is time measured as a fraction of the population size? ...
0
votes
1answer
76 views

Calculating number of amino acids in mRNA

Assuming there were 20 different amino acids and less than 40 types of different tRNAs found in this alien organism. How many amino acids would be found in the translational product of a ...
0
votes
1answer
68 views

Question about what the liver does NOT do

Which of the following functions is NOT performed by the liver? a) Storage of vitamins and minerals b) converts glucose to glycogen c) converts toxins to harmless chemicals d) produces bile I chose ...
4
votes
1answer
2k views

What are differences between formation of embryonic disc in chick and mammal embryo?

Exam question which got lowest average points in my university: 1/5 average. No markscheme available so my attempt below. I assume that embryonic disk prefers to germ disk such that Formation prefers ...
1
vote
1answer
171 views

Hardy Weinberg problem help!

The three common genotypes at the hemoglobin locus have very different phenotypes: SS individuals suffer from severe anemia, AS individuals have a relatively mild form of anemia but are resistant to ...
0
votes
0answers
16 views

Physiological function of CFTR gene product? [duplicate]

I just need a clarification. If I am to talk about the physiological function of the CFTR gene product? Then what should I do research and talk about? The only physiological function that I can ...
0
votes
1answer
135 views

Pathway mediates nitroglycerin-induced relief from angina pectoris [closed]

what kind of Pathway mediates nitroglycerin-induced relief from angina pectoris,please provide some idea...
2
votes
2answers
167 views

Hardy Weinberg Equilibrium after 5 Generations

1 There is a population not at HWE where red eye = $a^+$ (dominant) and white eyes = $a^-$. if $a^+/a^+ = 0.6$ $a^-/a^+ = 0.1$ $a^-/a^- = 0.3$ what are the frequencies of the $a^+$ and $a^-$ ...
6
votes
2answers
253 views

HIV and effectiveness of inhibitor cocktail over single inhibitor

I'm looking for clarification on the answer to this question. It's in my biochemistry class but I figured this is more Biology than Chemistry, so I'm asking it here. The question is: One of the ...
1
vote
1answer
54 views

Understanding intra and extracelullar concentrations (membrane potential)

I have 4 question (not homework) What happens to the cells membrane potential if: a) Na+ outside rises by 40mM b) K+ inside rises by 10mM c) K+ outside rises by 10mM d) A- (impermeable ion) ...
-4
votes
2answers
80 views

How are atoms created? [closed]

From small baby to the old age, we will be grown. We are composed of bunch of atoms, multitude of atoms. When you are grown from baby to the teen age, everyone will say "he has grown!" What do you ...
1
vote
1answer
75 views

How to estimate the DNA density in human sperm head? [closed]

I have got an estimate of sperm head volume from internet.Like consider it as a disk of order 4-5µm. Now I wanted to find the DNA density in the sperm head. How to find that?
3
votes
1answer
142 views

How does electrolarynx work?

I have heard that this is an effective replacement for patients who have a dysfunctional larynx, partly due to cancer. I am curious to know the inner working of this device and why such a robotic ...
0
votes
1answer
111 views

cellular respiration

What are the effects of addition of these chemicals to actively respiring cells ? Which of them would lead to INHIBITION of aerobic respiration ? Would cytochromes be actually taken up by cells ? ...
5
votes
1answer
62 views

Shade-loving Plants

In shade-loving plants, the light compensation point is reached at low irradiance because: A. Leaves have more chlorophyll per reaction center B. These plants have greatly reduced respiration rates ...
2
votes
2answers
105 views

Will climate change affect flower population?

There is a flower population elevated 1000 meters above sea level. If climate change causes a 12⁰C increase in temperature over the next 10 years, what will happen to the flowers?
0
votes
1answer
172 views

Why can CO₂ be transported dissolved in plasma?

Is it because CO2 is more soluble in water or has it got to do with the alkaline pH of plasma ?I here mean only aqueous CO2 transport from body cells to lungs.
2
votes
0answers
81 views

How many proteins are synthesized in human body throughout life?

My idea to calculate this is: Define up to what age will do the calculation. (for instance 60) Determine how many cells born and died up to that point in life. (by type of cell) Determine how many ...
2
votes
2answers
117 views

are the spontaneous generation and evolution the same idea but in a different time scale?

I was in my biology class, learning the history of spontaneous generation and how this idea was discarded. I told my teacher that is the same as evolution but in a different timeline. I Argue that ...
2
votes
1answer
31 views

Neuroscience: zapping an axon connected to thermoreceptor

Let’s say an experimenter has an electrode that can give a shock to a single axon. She takes that electrode and zaps an axon connected to thermoreceptors in the hand of her subject. I) What would the ...
0
votes
1answer
134 views

Answer the questions in one word with help of clues and images given [closed]

Name the things associated with Antonie Van Leeuwenhoek - (6 pictures are given for help and four of them are associated with these clues) a)Leeuwenhoek was the first to describe these and hence ...
4
votes
1answer
50 views

Correlating beta-lactamase expression to absorbance

When penicillin-resistant bacteria are grown in liquid culture media, β-lactamase is secreted into the medium. The supernatant of such a medium can be assayed for β-lactamase activity. ...
2
votes
1answer
101 views
0
votes
1answer
90 views

What is the importance of hydrogen bonds in water? and other questions: [closed]

These are extremely simple questions — basic biology — but I would like to make sure that the way I have answered is at the very least correct. Hydrogen bonds are very weak, so how is it possible ...
1
vote
1answer
51 views

How to measure the total number of cells in an average human body?

I have got one assignment to calculate the approximate sum total of all cells in the human body. How to tackle this problem? I know that the current statistics is $10^{13}$ cells. I wanted some hints. ...
5
votes
3answers
3k views

What are the advantages and disadvantages of using beta-galactosidase compared to luciferase as a reporter gene?

In the University labs, we have used Beta-galactosidase as a reporter gene to quantify the expression initiated by the stress-response promoter in yeast. This was done by exposing one of the two ...
4
votes
3answers
114 views

Membrane potential after exposure to glutamate

Neurons were kept in a physiological solution. During the resting phase, the membrane potential in the axoplasm of neurons was negative compared to the extracellular space and a potential ...
7
votes
3answers
7k views

Deciding between chi square and t test

I am always so confused whether to do a chi square test or a t test in the sums given by my biostats teacher. Does anyone have a simple rule to decide this?
4
votes
1answer
139 views

which signalling pathway is involved in cancer?

Columnar epithelial cells from the colonic mucosa are studied to identify abnormalities in cell signaling pathways. Abnormal epithelial cells from colonic adenocarcinoma are shown to have a mutation ...