Plant Cells Plants vs Animals Plant Organelles & Function Cell Walls – Composition & Function

Organelles found in both plant and animal cells  Nucleus - control center of the cell  Ribosomes – produce protein  Golgi Apparatus – packages protein to stay in the cell  Mitochondria – produces ATP (powerhouse)  Endoplasmic reticulum  Rough: packages proteins to leave the cell  Smooth: detoxifies poisons in cell

Organelles found only in plants  Cell wall  Large central vacuole  Plastids  Chloroplast  Tonoplast  Chromoplast  Leucoplast  Plasmodesmata

Cell Wall  Structural and mechanical support.  maintain and determine cell shape.  Keeps cell from exploding!  carbohydrate storage  protect against pathogens, dehydration, and other environmental factors.  Made up of 3 layers

Plasmodesmata (plasmodesma)  Plasmodesmata: small channels that connect the cytoplasm of plant cells to each other, forming a living bridge between cells.  Each cell is not completely isolated by the cell wall.

Plastids  Membrane bound organelle with various functions  Chromoplast – red, yellow, orange (caused by pigments – carotene & xanthophyll). Found in flowers & fruit  Leucoplast – colorless (lack of pigment). Storage of starch grains. Found in roots and seeds

Central Vacuole  Surrounded by a membrane called the tonoplast (type of plastid)  Stores water, salts, minerals, proteins, and pigments  Helps with growth & support

Chloroplast – the most important plastid of all!  Double membrane bound (like mitochondria)  Contain their own DNA which allows them to make their own enzymes  Location of photosynthesis  Green color comes from pigment chlorophyll

Basic Plant Cells 1. Parenchyma  Most abundant  Spherical w/ thin, flexible walls  Primary function is photosynthesis and storage  Example: flesh of fruit

Basic Plant Cells 2.Collenchyma -Long cells w/unevenly thickened walls -Walls stretch for growth, structures for support -Alive at maturity -Example – celery fibers

Basic Plant Cells

3.Sclerenchyma  thick and rigid cell walls  Cytoplasm disentegrates and walls remain for support at maturity (it’s dead)  2 basic types  Fibers (long and thin) - linen  Sclerids (short) - pears

Sclerenchyma Sclerid Fiber

Comparison of 3 basic plant cells