📌 NEET BIOLOGY – NOTES OF THE DAY
🗓 Day 5
📖 Topic: DNA & RNA

🔹 Key Points:
• DNA = Genetic material
• A = T (2 H bonds)
• G ≡ C (3 H bonds)
• RNA has Uracil
• mRNA carries code

📝 Practice MCQ:
Strongest base pair?
A) A=T
B) G≡C
C) A=U
D) C=T

👉 Answer: B) G≡C

📌 Revision Line:
"DNA is more stable than RNA"

#NEET #Biology #NCERT #DailyNotes #NEET2026

📌 NEET BIOLOGY – NOTES OF THE DAY
🗓 Day 6
📖 Topic: DNA Replication

🔹 Key Points:
• Semi-conservative nature
• Occurs in S-phase
• Helicase unwinds DNA
• Leading = Continuous
• Lagging = Okazaki fragments

📝 Practice MCQ:
Okazaki fragments found in?
A) Leading strand
B) Lagging strand
C) Both
D) None

👉 Answer: B) Lagging strand

📌 Revision Line:
"New DNA = Old strand + New strand"

#NEET #Biology #NCERT #DailyNotes #NEET2026

Class 10 Biology – Heredity
Topic: Colour Blindness (X-linked recessive disorder)

Question:
A man with normal vision marries a woman who is a carrier of colour blindness.

1. What are the chances that their son will be colour blind?
2. What are the chances that their daughter will be colour blind?
3. Show the cross using a Punnett square.

Solution:

Step 1: Genotypes
Let:
Xᴺ = Normal vision gene
Xᶜ = Colour blindness gene

Father (Normal) = XᴺY
Mother (Carrier) = XᴺXᶜ

Step 2: Gametes
Father produces: Xᴺ and Y
Mother produces: Xᴺ and Xᶜ

Step 3: Punnett Square

Xᴺ Y
Xᴺ XᴺXᴺ XᴺY
Xᶜ XᴺXᶜ XᶜY

Step 4: Result

XᴺXᴺ = Normal daughter
XᴺXᶜ = Carrier daughter
XᴺY = Normal son
XᶜY = Colour blind son

Final Answer:
1. 50% of sons will be colour blind.
2. 0% daughters will be colour blind.
3. 50% daughters will be carriers.

Conclusion:
Colour blindness is an X-linked recessive disorder. Sons have a higher chance of being affected because they receive only one X chromosome from their mother.

Class 10 Science – Heredity and Evolution
Topic: Dihybrid Cross

Question:
In pea plants, round seed shape (R) is dominant over wrinkled seed shape (r) and yellow seed colour (Y) is dominant over green seed colour (y).

A homozygous round yellow plant (RRYY) is crossed with a homozygous wrinkled green plant (rryy).

1. Write the genotype and phenotype of F₁ generation.
2. Perform the cross to obtain F₂ generation.
3. Write the phenotypic ratio of F₂ generation.
4. Name the law illustrated by this cross.

Solution:

Step 1: Parent Generation (P)
Round Yellow = RRYY
Wrinkled Green = rryy

Gametes:
RRYY → RY
rryy → ry

Step 2: F₁ Generation
RY × ry

All offspring = RrYy

F₁ Genotype = RrYy
F₁ Phenotype = Round Yellow (because R and Y are dominant)

Step 3: F₁ Self Cross
RrYy × RrYy

Gametes formed by each parent:
RY, Ry, rY, ry

Punnett Square:

RY Ry rY ry
RY RRYY RRYy RrYY RrYy
Ry RRYy RRyy RrYy Rryy
rY RrYY RrYy rrYY rrYy
ry RrYy Rryy rrYy rryy

Step 4: F₂ Phenotypic Ratio

Round Yellow = 9
Round Green = 3
Wrinkled Yellow = 3
Wrinkled Green = 1

Phenotypic Ratio = 9 : 3 : 3 : 1

Step 5: Law Illustrated
This cross explains Mendel’s Law of Independent Assortment, which states that inheritance of one trait is independent of inheritance of another trait.

Notes for the Day ✌️

❁ In some plants sepals of the flower 🌹 remain attached after fertilisation during embroygenesis. E.g., Tomato 🍅, Brinjal, Strawberry 🍓. 

❁ The zygote develops into embryo after which the ovule becomes the seed and ovary becomes the fruit 🍏

❁  Inside the mature seed is the progenitor of the next generation, the embryo. 🙌

❁  The fruit develops a thick wall called pericarp that is protective in function.🔥

❁ After dispersal, seeds🌱 germinate under favourable conditions to produce new plants. 🌾

1 Mark Questions (Very Expected)
1. Define capacitation.
→ Functional changes in sperm inside female reproductive tract to fertilize ovum.
2. What is colostrum?
→ First milk produced after childbirth, rich in antibodies.
3. Name the hormone responsible for ovulation.
→ LH (Luteinizing Hormone)
4. What is parturition?
→ Process of childbirth.
5. Name the site of fertilization in humans.
→ Ampullary-isthmic junction of fallopian tube.
6. What is amniocentesis? Why is it banned?
→ Prenatal sex determination technique; banned to prevent female foeticide.
2 Marks Questions
Q1. Differentiate between spermatogenesis and oogenesis.
Spermatogenesis
Oogenesis
Occurs in testes
Occurs in ovaries
Produces 4 sperms
Produces 1 ovum
Starts at puberty
Starts before birth
Q2. Write functions of placenta.
Supplies oxygen and nutrients
Removes waste
Secretes hormones (hCG, hPL, estrogen, progesterone)
Q3. What are the major events of menstrual cycle?
Menstrual phase
Follicular phase
Ovulation
Luteal phase
3 Marks Questions (Highly Important)
Q4. Draw and label human male reproductive system.
Very frequently asked.
Focus labels:
Testis
Epididymis
Vas deferens
Seminal vesicle
Prostate gland
Penis
Urethra
Q5. Draw and label female reproductive system.
Important labels:
Ovary
Fallopian tube
Uterus
Cervix
Vagina
Q6. Explain menstrual cycle briefly.
Prepare full explanation with 4 phases + hormone role.
Q7. What are the different methods of contraception?
Natural methods
Barrier methods
IUDs
Oral pills
Surgical methods
Q8. Explain test tube baby programme (IVF).
Steps:
Ovum collection
Sperm collection
Fertilization outside body
Embryo transfer
5 Marks Questions (Most Expected)
Q9. Describe the process of fertilization and implantation.
Must prepare in sequence:
Sperm reaches ampullary-isthmic junction
Acrosomal reaction
Fusion of gametes
Zygote formation
Cleavage
Blastocyst
Implantation
Q10. Explain events of pregnancy till parturition.
Includes:
Implantation
Placenta formation
Hormonal support
Foetal development
Parturition
Q11. What are STDs? Mention symptoms, causes and prevention.
Examples:
AIDS
Gonorrhoea
Syphilis
Prevention:
Safe sex
Hygiene
Avoid multiple partners
Regular medical check-up
Q12. Explain population explosion and birth control measures.
Very common from reproductive health.
Most Important Diagrams
Prepare these perfectly:
✅ Male reproductive system
✅ Female reproductive system
✅ Structure of sperm
✅ Graafian follicle
✅ Blastocyst

Must watch video