CELLULAR BASIS OF LIFE AND CELL PHYSIOLOGY

WEEKS 4-5

Cell

is the smallest unit that is capable of performing life functions.

The Cell Theory

● All organisms are composed of one or more cells.

● Cells are the smallest living units of all organisms.

● Cells arise only by division of a previous existing cell

organisms

All ____________ are composed of one or more cells

smallest

Cells are the ________ living units of all organisms

division

Cells arise only by __________ of a previous existing cell

two types of cells

prokaryotic and eukaryotic

Prokaryotic

is a unicellular organism that lacks a membrane-bound nucleus, mitochondria or any other membrane-bound organelle.

Eukaryotic

are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes which have no membrane-bound organelles.

Genetic material

● Single circular molecule of DNA in prokaryotes

● Double helix located in nucleus in eukaryotes – nuclear envelope (double membrane)

prokaryotes

genetic material which is a single circular molecule of dna in __________

eukaryotes

genetic material which is a double helix located in nucleus in ______

Cytoplasm

is surrounded by plasma membrane and encased in a rigid cell wall composed of peptidoglycan.

Plasma membrane

encloses the cell.

Compound microscope

magnify in stages using multiple lenses.

Transmission electron microscope

electrons transmitted through specimen

Scanning electron microscope

electrons beamed onto surface of the specimen.

Nucleus

repository for genetic material

nucleus

- directs activities of the cell

- usually single, some cells several, RBC none

Nucleolus

region of intensive ribosomal RNA synthesis

Chromosomes

DNA of eukaryotes is divided into linear chromosomes

cell division

Chromosomes Exist as strands of chromatin, except during _______________

histones

Chromosomes are associated with packaging ________, packaging proteins

Gene

a short length of DNA on a chromosome which is a unit determining an inherited character.

gene

It consists of a chemical substance called deoxyribonucleic acid (DNA)

DNA

is responsible for telling the cell to make the right type of protein & control the metabolic activities of the cells.

Alleles

Alternative forms of genes on the same position of the homologous chromosomes which control the same character but have different expressions

Endomembrane System

compartmentalizes cell, channeling passage of molecules through cells’ interior.

Endoplasmic Reticulum

● Largest internal membrane

Endoplasmic Reticulum

● Composed of Lipid bilayer

endoplasmic reticulum

● Serves as system of channels from the nucleus

endoplasmic reticulum

● Functions in storage and secretion

Rough ER

studded with ribosomes

Smooth ER

few ribosomes

Golgi Apparatus

collection of Golgi bodies

Vesicles

a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer.

plasma membrane

Vesicles form naturally during the processes of secretion,

uptake and transport of materials within the ___________________

secretion

Vesicles form naturally during the processes of ________,

uptake and transport of materials within the plasma membrane.

uptake

Vesicles form naturally during the processes of secretion,

__________ and transport of materials within the plasma membrane.

transport

Vesicles form naturally during the processes of secretion,

uptake and _________ of materials within the plasma membrane.

Lysosomes

membrane-bound vesicles containing digestive enzymes from Golgi

Microbodies

enzyme-bearing, membrane-enclosed vesicles

Peroxisomes

contain enzymes that catalyze the removal of electrons and associated hydrogen atoms

Ribosomes

are RNA-protein complexes composed of two subunits that join and attach to messenger RNA

ribosomes

- Site of protein synthesis

ribosomes

- Assembled in nucleoli

Mitochondria

bounded by exterior and interior membranes

mitochondria

- Interior partitioned by cristae

Chloroplasts

have enclosed internal compartments of stacked grana, containing thylakoids.

Grana

closed compartments of stacked membranes

Thylakoids

disc shaped structure – light capturing pigment

Stroma

fluid matrix

THEORY OF ENDOSYMBIOSIS

explains how eukaryotic cells may have evolved from prokaryotic cells.

Symbiosis

is a close relationship between two different organism

theory of endosymbiosis

This host cell engulfed or ate a prokaryotic cell capable of aerobic respiration. This is where the mitochondria originated.

Cytoskeleton

network of protein fibers supporting cell shape and anchoring organelles.

Central vacuole

often found in the center of a plant and serves as a storage facility for water and other materials.

Cell wall

primary walls, middle lamella and secondary walls of a plant cell

Primary walls

laid down while cell is growing

Middle lamella

glues cells together

Secondary walls

inside the primary cell walls after growth

ANIMAL CELLS

- it lacks cell walls

- form extracellular matrix

- provides support, strength and resilience.

cell membranes

All cells have _______________

functions of cell membranes

a. Controls what enters and exits the cell to maintain an internal balance called homeostasis

b. Provides protection and support for the cell

structure of cell membrane

a. Lipid Bilayer – two layers of phospholipids

lipid bilayer

● Phosphate head is polar ( water loving)

● Fatty acid tails non-polar (water fearing)

● Proteins embedded in membrane

pores

Cell membranes have _________

Selectively permeable

allows some molecules in and keeps other molecules out.

Types of Cellular Transport

passive and active transport

Passive Transport

cell doesn’t use energy

types of passive transport

diffusion, facilitated diffusion and osmosis

Diffusion

movement of a substance from an area of high concentration to an area of low concentration.

Facilitated Diffusion

diffusion of specific particles through transport proteins found in the membrane.

Osmosis

diffusion of water through a selectively permeable membrane

Active Transport

cell does use energy

types of active transport

protein pumps, endocytosis and exocytosis

Protein Pumps

transport proteins that require energy to do work.

Endocytosis

taking bulky material into a cell.

Exocytosis

forces material out of cell in bulk

Hypotonic Solution

the solution has a lower concentration of solutes and a higher concentration of water than inside the cell (low solute; high water)

inside

Result of hypotonic solution: Water moves from the solution to ___________ the cell. Cell swells and bursts open (cytolysis)

cytolysis

Cell swells and bursts open

Hypertonic Solution

the solution has a higher concentration of solutes and a lower concentration of water than inside the cell (high solute; low water)

solution

Result of hypertonic solution: Water moves from inside the cells into the _________. Cell shrinks (plasmolysis)

plasmolysis

Cell shrinks

Isotonic Solution

the concentration of solutes in the solution is equal to the

concentration of solutes inside the cell

equally

Result of isotonic solution: Water moves __________ in both directions and the cell remains same size (dynamic equilibrium)

dynamic equilibrium

Water moves equally in both directions and the cell remains same size

Photosynthesis

makes glucose and oxygen, which are then used as the starting products for cellular respiration

Cellular respiration

makes carbon dioxide and water (and ATP), which are the starting products (together with sunlight) for photosynthesis.

Cellular reproduction

is a process by which cells duplicate their contents and then divide to yield two cells with similar, if not duplicate, contents.

interphase

• cell grows and develops

• towards the end, dna doubles (chromosomes double)

prophase

• chromosomes are visible

• nuclear membrane disappears

• nucleolus disappears

metaphase

• chromosomes line up across center

• spindle fibers attach to center of each chromosome

anaphase

• chromosomes split

• each half is pulled to opposite side of cell

telophase

• chromosomes cluster in the center of each new cell

• nuclear membrane begins to form

• cells begin to separate

cytokinesis

• cytoplasm divides

• two daughter cells form

  • same number of chromosomes as parent cell

mitosis

is prophase, metaphase, anaphase and telophase