Lesson 3: CRSC Upstep Cell

Cell

The smallest structure in the universe capable of growth and reproduction. It is the basic unit of every living organism.

Cell

an autonomous living system capable of independent existence and propagation the fundamental morphological unit of plant body

Plant cells

contain chloroplasts that carry out photosynthesis

plant cell

is surrounded by a rigid cell wall. The walled cell and its adjacent wall are cemented together by middle lamella.


CELL WALL

Provides mechanical protection and rigidity to the plant cell

Cell wall

Consists of cellulose that overcomes pressure due to its elastic property Composed of cellulose, hemicellulose, pectic substances, organic and inorganic substances, lignin, enzymes, protein and water

Middle lamella

where pectin cements adjacent cells together

Primary wall

thin, not rigid, stretched as the cell grows; layer formed before and during growth of the plant cell; consists of cellulose microfibril; has primary pit fields, thin areas that are transversed by numerous protoplasmic strands called plasmodesmata

Secondary wall

rigid, thick, formed after cell completes growth

Cytoplasm

Gel like fluid suspending organelles and internal membranes; distributes substances (absorbed externally or released by nucleus organelles) via cytoplasmic streaming (cyclosis).
Plasmalemma/Plasma membrane

Plasmalemma/Plasma membrane

coordinates the formation of cell wall microfibrils

Endoplasmic Reticulum

flattened disks or tubular sacs

rough endoplasmic reticulum

(with numerous ribosomes)

smooth endoplasmic reticulum

(lack ribosomes)

Rough ER

involved in the synthesis of lipid

Smooth ER

involved in the synthesis of membrane proteins and secretory proteins

Golgi Apparatus

collective term for all dictyosomes or golgi bodies

Golgi Apparatus

involved in the synthesis of polysaccharides and glucose units for cell wall formation

Golgi Apparatus

secretes protein and carbohydrates from the cell to the exterior part (ex. nectar coming out from the flower)

Mitochondria

small cylindrical organelles enclosed by two unit membranes

Outer membrane

permeable to smaller particles; contains the respiratory chain component and enzymes for ATP synthesis

Inner membrane

impermeable and folded into numerous cristae, and the site of respiration energy source for plants body maintenance, growth, and development)

Plastids

differentiated into system of membrane (2 units) and ground substance, the stroma

Chloroplast

site of photosynthesis

Chloroplast

involved in amino and fatty acid syntheses

Chloroplast

provides space for temporary starch storage

Chromoplast

responsible for the yellow, orange or red colors of many flowers and other plant part attracts insects and other animals

Leucoplast

nonpigmented plastids but once exposed to light, may develop into chloroplasts


Microbodies

are spherical, single membrane organelles

0.5 to 1.5 mm diameter

Size of microbodies in diameter

Peroxisomes

play a role in glycolytic acid metabolism linked to photorespiration.

Glyoxysomes

contain enzymes for converting fats into carbohydrates during seed germination.

Cytoskeleton

an organized cytosol into a three dimensional network of fibrous protein types

Microtubules

Long, thin, cylindrical structures and of varying lengths; each is made up of subunits of the protein called tubulin Functions

24mm in diameter

diameter of microtubules

Microtubules

involved in the orderly growth of the cell wall, especially the control of cellulose microfibril alignment

Microtubules

formation of cell plate (the initial partition of dividing cell)

Microtubules

involved in the movement of flagella and cilia of which microtubules are important components

Microfilaments

consist of two actin chains (similar to that of muscle tissue) that maintain in a helical fashion and play a causative role in cytoplasmic streaming

Ribosomes

small particles containing an equal polyribosome or polysomes

17 to 23 NM

diameter of ribosomes

Vacuoles

enclosed by a unit membrane called tonoplast.

Vacuoles

They are the dumping house of the cell and contain water and other substances.

Functiona of vacuoles

Absorb toxic products,Store various metabolites & Break down macromolecules and recycle their components within the cell

Nucleus

Contains the genetic information indispensable for the cell's life and metabolic function

Nucleus

Controls the activities of the cell by determining which protein molecules are produced and when they are produced

Nucleus

Stores the genetic information

Cell Cycle

Refers to the sequence of events that cell undergoes as it grows, replicates its DNA and divides into two daugter cells

Interphase

Phase where cell grows, replicates its DNA and prepares for division

G1 phase

The cell grows and performs normal functions.

S phase (Synthesis)

DNA replication occurs, resulting in the duplication of chromosomes.

G2 phase (Gap 2)

The cell continues to grow and prepares for mitosis, checking for any DNA errors.

M phase (Mitotic phase)

This includes mitosis (the division of the cell's nucleus) and cytokinesis (the division of the cytoplasm), resulting in two identical daughter cells.

Cell division

on the other hand, is the process by which a parent cell divides into two or more daughter cells.

Mitosis

A type of cell division where one parent cell divides to produce two genetically identical daughter cells. It involves stages such as prophase, metaphase. anaphase, and telophase, followed by cytokinesis.

Meiosis

A type of cell division that reduces the chromosome number by half, producing four genetically unique daughter cells (gametes), important for sexual reproduction.

cisternae

stack of flattened hollow disks are called