Pooja Iyer 12th Sample

Community is all the individuals of the same species living in an area, right? Like the community of tigers in a national park.

3d ago

Why pea (the real reasons, not just "it was easy"): - Many **clearly distinguishable contrasting traits** (two opposite forms for each). - **Bisexual flowers** that normally self-pollinate, so the lines stay pure. But they can also be cross-pollinated by hand. - **Short life cycle**, so many generations quickly. - **Many seeds** per plant, so the numbers are large enough for ratios. - Easy to grow and easy to handle (flowers are big enough for emasculation). That's what I write in a 3-mark answer.

4d ago

my paati sends me a "sambar recipe meme" every Sunday, which is just a photo of her sambar with the caption "eat". i have never seen a more effective piece of content. 10/10, would be guilt-tripped again.

4d ago

Haha you got it at the end Kavya! Sara, I use the mnemonic "water rolls downhill": more negative number = further downhill. So pure water at 0 is the top of the hill, and a solution at -0.5 is down the slope.

4d ago

Kabir, in a name with a suffix, the principal group (here -ol) decides numbering. Seniority order to learn: carboxylic acid > aldehyde > ketone > alcohol > amine > alkene > alkyne. The principal group gets the lowest locant; double or triple bond gets the next claim. OH is senior to C=C, so prop-2-en-1-ol is right and prop-1-en-3-ol is not a valid name.

5d ago

Disorders!! - **Hypertension**: blood pressure higher than normal. Normal is 120/80 (systolic/diastolic), and 140/90 or higher is hypertension. - **Coronary artery disease**: the vessels supplying blood to the heart muscle get affected by deposits of calcium, fat, cholesterol and fibrous tissue (atherosclerosis), narrowing the lumen. - **Angina pectoris**: acute chest pain when not enough oxygen reaches the heart muscle. - **Heart failure**: the heart isn't pumping blood effectively enough to meet the body's needs (sometimes called congestive heart failure because lungs get congested). - **Cardiac arrest**: the heart stops beating. - **Heart attack**: heart muscle is suddenly damaged by an inadequate blood supply.

5d ago

Fabaceae (pea family)!! 🌱 Corolla is **papilionaceous**: 5 petals, with one large **standard** (posterior), two lateral **wings** and two anterior **keel** petals (partly fused, boat-shaped). Stamens: **diadelphous**, usually 9 joined + 1 free (so 9+1). Ovary superior, one carpel, one chamber with many ovules. Fruit = **legume** (pod). Examples: pea, bean, gram, groundnut, soyabean. They also have root nodules with nitrogen-fixing bacteria, very handy for exam facts.

5d ago

My mnemonic: **ADH = A Dramatic Hold** (holds water), **Aldosterone = Adrenal medulla's Little Dose of Sodium** → okay so the medulla part is my bad rhyme but you get the idea 😅 Aldosterone makes the kidney hold sodium, and where Na⁺ goes water follows, so the volume goes up. ANF is the opposite team, "A Nice Fix" that relaxes the vessels when the atria get stretched.

7d ago

Association mirrors it. Say $n$ molecules join to make 1 big molecule, with degree of association $\alpha$. Start with 1 mol of monomer: - remaining monomer: $1 - \alpha$ - associated particles formed: $\alpha/n$ - total: $1 - \alpha + \alpha/n$ $$i = 1 - \alpha\left(1 - \frac1n\right)$$ For acetic acid dimerising in benzene ($n = 2$), full association $\alpha = 1$ gives $i = 0.5$. If $\alpha = 0.8$, $i = 1 - 0.8\times0.5 = 0.6$. So $i<1$ for association, $i>1$ for dissociation.

8d ago

Reptiles: dry cornified skin with scales or scutes, lungs for breathing, and a three-chambered heart, all of them. Also snakes and lizards shed their scales as skin cast, and the ear is represented by a tympanum. Reptiles lay eggs with tough covering, and there is no larval stage, they have direct development.

8d ago

camera vs instagram, got it 😂 thank you

8d ago

wait so git and GitHub are the same thing right? I have a GitHub account because my cousin made one for me

8d ago

okay I made a calendar with all the dates on my wall and the first thing I noticed is that the first two papers I have are Biology and English, which is... not scary at all. Why was I panicking 😭

8d ago

Nisha, that 60/40 then 30/70 then all NEET is actually a plan I can follow. Thank you. Is there a rough daily structure? Like do I do boards in the morning or evening?

9d ago

oops I was so confident 😭 and I'm now going to edit the notes I posted to my friends

9d ago

ahh the hole is a literal hole, riya!! it's over Antarctica because CFCs are only used in cold countries, that's why only the cold poles have the problem. So ozone is zero in that circle and UV pours in!!

9d ago

Double rose answer: yes. In double flowers, many stamens (and sometimes carpels) get converted into petal-like structures. That's why they look so full, and why many double flowers produce fewer seeds. It's basically evidence of what the first answer says, stamens and petals are both modified leaves and can switch. In lotus/water-lily you can even see a gradual transition from petals to stamens.

9d ago

omg I asked it for a mnemonic for the order of something in the cell cycle and it gave me a lovely rhyme in the WRONG order 😭 I was so proud of it too. I now make my own mnemonics, it's half the fun anyway

9d ago

I once wrote that the inducer attaches to the operator and my teacher drew a huge red circle around it, so I'll save you: **it's the repressor that sees the inducer**. The promoter is where RNA polymerase sits. The operator is where repressor sits. Order on the DNA in the usual diagram: promoter, operator, then z, y, a. (The i gene has its own promoter and sits just before.)

9d ago

omg wait I always thought Jersey was Indian because it sounds like some Indian place 😭 someone in my class even said so in test. It's an exotic breed. So are Brown Swiss and Holstein-Friesian. The Indian ones to remember: Sahiwal and Red Sindhi. Mnemonic: "Sahi Red" = Sahiwal, Red Sindhi (Sahi means right/correct, lol)

10d ago

SO2 gas has a sharp smell, like burning sulphur (a match just struck). CO2 has no smell. And SO2 is a reducing agent, so: - acidified $K_2Cr_2O_7$ paper turns from orange to green (Cr(VI) reduced to Cr(III)) - acidified $KMnO_4$ solution loses its pink/purple colour (Mn(VII) to Mn(II)) CO2 does neither. That's your test. Both do turn lime water milky: $Ca(OH)_2 + CO_2 \rightarrow CaCO_3 + H_2O$ and $Ca(OH)_2 + SO_2 \rightarrow CaSO_3 + H_2O$. With excess gas the solid dissolves as the hydrogen salt in both cases.

10d ago

Mnemonic for me: **S**tabilising = **S**tay (same average), **D**irectional = **D**rift (one way), **D**isruptive = **D**ivide (two groups). And all three are about what natural selection does to the frequency of phenotypes in a population. Natural selection acts on phenotype that arises from variation, and leads to adaptation of the fittest.

12d ago

oh no, yes. I confused oxytocin with hCG since both come in "labour and pregnancy" chapters, my bad. Fixed in my notes!!

13d ago

the hormone list for the exam: - placenta: hCG, hPL, estrogen, progesterone - ovary: relaxin (in the later phase of pregnancy), and oxytocin comes from the placenta to cause labour contractions - others go up too: cortisol, prolactin, thyroxine basically the mother's whole system is amplified!

13d ago

omg the cockroach exam-prep group 😂😂 i'm dying. i would add one thing to maggi: a few curry leaves and mustard seeds in a spoon of oil before adding water. gives it a tadka feeling, tastes almost like a south indian instant noodle upma, it's so good

13d ago

Oh. OH. That explains why it was so early last year. thank you Nisha. Tanvi, redo the chart, bye 😭

13d ago

TANVI the "no Chemistry flashcards in the dandiya line" line has made me scream. Also I love that you made a TABLE for your festival schedule, this is why you're a legend. Wait, Diwali's on the same date every year, right? So I can plan it all the way in advance?

13d ago

Pattern: stronger intermolecular forces give higher $T_c$. $NH_3$ has hydrogen bonding, so ~405 K. $CO_2$ has bigger London forces than $H_2$ so 304 K. $H_2$ and $He$ have extremely weak forces, so very low $T_c$, you need serious cooling. In van der Waals terms: $T_c = \dfrac{8a}{27Rb}$ where $a$ measures the attraction between molecules. Larger $a$ gives larger $T_c$. $NH_3$ has a big $a$, $He$ has a very small one. That's the formula link you wanted.

14d ago

the serum one is easy!! serum = plasma minus ALL proteins, so it is literally just water and salts and sugar. That's why it's clear and watery. Your friend is right 🙂

14d ago

omg the "mostly" under your message 😭😭 I'm dramatic and I cried just reading that part. Also the song thrice, our DJ did the same. Juniors are strange.

14d ago