Biology

Hello everyone, I'm slightly confused here. After ovulation, progesterone increases markedly. Now progesterone is also used as a contraceptive for creating a hostile environment for fertilisation and not allowing sperm to enter. So after ovulation how does fertilisation occur normally, if progesterone increases right after that. I see that it takes like 5 days for progesterone to peak. So does fertilisation have to occur before progesterone increases a lot. Also after fertilisation, doesn't the effects of progesterone cause any problems to the fertilized egg. Thanks

Hello everyone, Quick questions. What do they mean by different polarities in anti parallel DNA strands. Are they referring to some chemical polarity or simply the fact they run in opposite directions. I'm confused with DNA replication. DNA polymerase can only synthesize DNA in 5' to 3' direction. I don't understand how this could cause a lagging strand. For example 5'------------------------3' (1st strand) 3'------------------------5' (2nd strand) Can't two DNA polymerases work in opposite directions in DNA replication. One from 5' to 3' in the first strand(moving to the left) and the other 5 to 3 in the second strand(moving to the right) They …

I came up with a thought the other day: There is a sort of hierarchy in the natural world, pertaining to both living and nonliving things, but focuses around living things. You know: -atom -molecule -organelle -cell (this is where life begins) -tissue -organ organ system -organism (although organism can come at the cell level, with unicellular organisms) -population -community -ecosystem -biome -biosphere But could there be something beyond biosphere? Such as two biospheres interacting? There are some problems with this idea, such as being able to get two biospheres close enough together to exchange materials without having them collide. If…

Hello everyone, First of all I don't know much about cancer. I'm assuming cancer is some mutation in dna and causes the cells to uncontrollably replicate. So let's say a person has lymphoma. Now this cancer spread into lungs? Then what happens? Do lung cells start to replicate there or lymphoid cells start to replicate there?If lung cells start to replicate, how does a lymphomatic cancerous cell spread the mutation to a lung cell? I mean it is not like a virus that can inject DNA right? Also how do cancers spread through lymphatic system? Lymphatic system can not carry cells right, only interstitial fluid so how does cancer spread through them? Thanks

Hello everyone, I can understand how liver failure can cause jaundice, but not vise versa. Please help. Thanks

I have trouble understanding this question and I dont know how to solve this step by step. Can anyone help me? Thanks 1 in 1700 US Caucasian newborns have cystic fibrosis. C for normal is dominate over c for cystic fibrosis. 1) What is the equation for Hardy-Weinberg. What do p,q, 2pq, p^2, and q^2 represent? 2) Why are individuals with the recessive (cc) phenotype so important when calculating p and q? Thanks

Any comments on this? My impression is that it's largely a political attempt to accomodate genetics with taxonomy. Similar things happen in my field where people try to accomodate QM and classical physics when there isn't really any need. QM is the rock star, and classical physics wants to bask in the same spotlight. Shrug. As an engineer classical physics remains much more useful to me even if the prevailing opinion is that QM is more phenomenological. Anyway, I 'm not a biologist so I was looking for other opinions on Twin Nested Hierarchy.

I was wondering, if you impregnated an organism with foreign genes - that is genes which are not known or recognized by that organism (its genome). Would the developed embryo (later on) contain DNA with no function within its genome, in other words 'junk DNA'. And would this be true due to the foreign DNA literally having no role to play within the organism for which it has no (natural) function...

Topic says all I'm asking.

which human cells do not have entire DNA sequence genome to produce every protein type? I don't really understand what the question wants , does it mean which cells doesn't have a nucleus or something......

How could I somehow get syrup to travel up and down a tube via passive transport? It's for a school project. I can't help the project. I might be able to get away with starting the siphon, then letting it do whatever, though. I just don't know how I'd get the syrup to travel back up? unless someone has other ideas? thanks. Btw, it's supposed to replicate phloem.

is it possable to catch the same cold or sickness twice or does your body learn to deal with that paticular type of bacteria?

Do any have you have ideas for good nature and biology related projects for young people? I regularly write articles about nature related activities for a nature magazine. I have recently exhausted my ideas for articles, and was wondering if any of you knew of great demonstrations that demonstrate a certain aspect of how nature works. The activity should be for ages 10-16 and should only require easily obtainable items. I have a more detailed description of what I am doing and looking for on my website at http://www.geeksbrain.net/Projects/projects.html. Thanks in advance, to all of you who have brainy ideas

So, I have this quiz question I'm looking over. This really takes the cake. I got it right, but I think the question is illogical and invalid, thus there is no T/F answer. I marked true. But the important thing here would be that the question is totally illogical: The growth stage occurs before mitotic division (interphase is before mitosis). What do you think of this situation? Is this a valid question that has an answer?

How many kilojoules does your body burn from studying?

Hi people, Not sure if the bacteria actually lives inside the chicken's tissues or just in its intestines. Of course, we know one should "cook chicken fully", etc etc. Is that cuz the bacteria could be on the exterior surface of the meat, like e coli gets on the surface of steak. UNlike trichina in pork, which lives inside the tissues, I understand. So, is the salmonella advice on chicken cuz it can get on the surface from preparation practices/accidental contact, or otherwise? I know on eggs, the bacteria does not live in the egg itself, but can be transferred to the egg once cracked and it runs out over the shell........thats the danger there. Thanks!

I came across the following paragraph on the working of muscles in a book: Muscles bring about movement by contracting (shortening) & relaxing (lengthening). One end of a muscle is attached to a movable bone where as the other end is attached to a fixed bone. When the muscle contracts, it pulls the movable bone. Since muscles are only capable of pulling, they work in pairs. Now what does the line in bold mean? Aren't muscles capable of pushing? Thanks, Ron

how thick is the human scalp?

Hello everyone, I have a quick question. Ok the endoneurium is a layer of delicate connective tissue that encloses the myelin sheath of a nerve fiber within a fasciculus. Now my question is supporting cells of the nervous system like glial cells usually connect two nerve fibres together, so do they lie outside the endoneurium? Thanks

thinking about forensic pathology, what, if any, would be the signs that a body or part of a body had been frozen and then thawed at some point?

Hello everyone, I just read that vitamin D increases the activity of osteoblasts and osteoclasts (secondary effect). Why does vitamin D increase the activity of osteoblasts if it is trying to increase serum calcium levels? Also bone matrix is made up of type 2 collagen but osteoblasts secrete type 1 collagen. Why is that? Thanks

How much protein should you consume from one sitting to take the maximum benefits of the protein available? I've been told that if you eat too much protein some of it will be converted to fat...so how much protein should you consume in one sitting to not convert any to fat?

I'm dealing with artificial intelligence as a hoby.And to creat a intel feeling machine i m collectin data. Even if you have little assumptions please dont hesitate to share The question is: As we are learning new logics we link neurons by synapses and creating new paths in our mind. But i wonder how two neurons can know the other one is there and grow its one of the branches. Is there a chemical going through the space between them to say come,grow im here! Thanks for any reply.

GE Salmon, a fish genetically engineered from three different fish. There seems to be a huge amount of emotion being touted as reason not to eat it but very little if any real evidence it could be harmful. Will you eat it when it comes on the market?

I'm reading about embryonic germ cells from one of my course books. It says that EG cells should be able to turn into any cell. Then again, it seems to say it can turn into the three germ layers. However, from the way I'm interpreting this, it would appear that EG cells are pluripotent and not totipotent. So, I'm unsure as to whether or not consider them totipotent or pluripotent. Perhaps this is really a contextual issue? The attached image has part of my text that I am discussing. Note the term "pluripotent" and the phrase "...all the cell types..."