THE FORMATION OF DICOT EMBRYO AND MONOCOT EMBRYO The formation of embryos in flowering plants begins after fertilization, when the zygote (formed by the fusion of the male and female gametes) undergoes a series of divisions and differentiations. Though the initial stages of development are similar in both dicots and monocots, the final structure of the embryo differs significantly.
Dicot Embryo Formation– In dicot plants (e.g., bean, pea), the zygote first divides asymmetrically into a small terminal
1. Fertilization
Frogs reproduce through external fertilization, where the female lays eggs in water, and the male releases sperm over them. Fertilization occurs in the animal hemisphere of the egg. This process forms a diploid zygote. The point of sperm entry determines the gray crescent, which helps in the later development of the body axis.
2. Cleavage (Early Cell Division)
The zygote undergoes holoblastic, unequal, and radial cleavage. The first two cleavages
Explain how an OS can facilitate installation of a new device without any need for recompiling the OS. Modern operating systems use loadable kernel modules (LKMs), which allow device drivers to be loaded at runtime without recompiling the kernel. Additionally, they use Plug-and-Play (PnP) systems and hardware abstraction layers (HAL) to detect and configure new devices automatically.
This makes it easy to add printers, USB drives, and other hardware dynamically. Why is printer output typically spooled
MEMORY MODELS Model A (MSDOS): Large user space at top, small RAM at bottom | Fast execution, long boot | No protection Model B: Small ROM at top, small user space at bottom | Protected OS but slow (entire OS must be read) | Not flexible Model C (Win11): Select drivers at top, large user space in middle, RAM at bottom | Fast + secure (key drivers in ROM) MEMORY PROTECTION & MANAGEMENT Relocation Problem: Without abstraction, loading multiple programs ca1.5uses incorrect memory addresses Base
Block Devices: Stores information in fixed-size blocks, transfers are in units of whole blocks(ex: hard drives, SSDs, USB drives). Character Devices: delives/acccepts streams of charcters, w/o regard to block struc, not addressable, no seek op(ex: keyboard,mice,serial ports). Port-Mapped (Isolated I/O): I/O devices have a separate address space, special instructions IN & OUT used to access devices. Memory-Mapped I/O: Device registers are mapped into system memory, use regular load and store
UNIT-I: ATOMIC STRUCTURE
Bohr’s Atomic Theory
Bohr proposed that electrons revolve in specific circular orbits around the nucleus without radiating energy. These orbits are quantized and labeled by the principal quantum number n. The angular momentum of the electron is given by mvr = n(h/2π). The energy of an electron in a hydrogen-like atom is E = –13.6 Z²/n² eV. When an electron jumps between energy levels, radiation is absorbed or emitted: ΔE = hν = hc/λ.
Limitations of Bohr’s Theory
Turing Machine
The Turing machine is a collection of following components. M = (Q, E, Γ, δ, q0 ,Β, F) 1) Q is a finite set of states. 2) T is finite set of external symbols. 3) E is a finite set of input symbols. 4) A or b or B e T is a blank symbol majorly used as end marker for input. 5) 8 is a transition or a mapping function.
Design of TM The Turing machine can be modelled with the help of following representation.1) The input tape having infinite number of cells, each cell containing one
File System: Manages how data is stored and retrieved on disk. Disk = sequence of fixed-size blocks -> only 2 ops: read(k), write(k). Must: 1.) Store large amounts of data. 2.) Keep data after process ends. 3.) Allow multiple processes to access same data. File Types & Structure: File Types: Executable, Text, Archive. File Structures: Byte Sequence (eg: .txt), Record Sequence (eg: DB), Tree (eg: XML). File Operations: Create, Delete, Open, Close, Read, Write, Append, Seek, Get/Set Attributes,...
Revolução liberal portuguesa:
Causas: Resistencia do bloquei continental que levou as invasões francesas;
Fuga da familia real para o Brasil (1808);
Governo do país na mão dos ingleses;
Abertura dos portos brasileiros ao comercio internacional;
grave crise politica, económica e social.
Revolução liberal portuguesa Uma associação secreta (sinedrio) desencadeou a revolução liberal, no porto, a 24 de setembro de 1820.
Constituição de 1822- Monarquia constitucional: Soberania residia