Cytogenetics - Cell & Cell Cycle

Cell

a collection of living matter enclosed by a barrier that separates the cell from its surroundings

A cell is?

The Basic unit of life

Robert Hooke

A great many little boxes; coined the term cell

Antonie Van Leeuwenhoek

Animalcules

Matthias Schleiden

All plants are made up of cells

Theodor Schwann

All plants and animals are made up of cell

Rudolf Virchow

Every living thing is made of cells and cells come from other cells

Types of cells

prokaryotes and eukaryotes

Types of eukaryotes

Animal cells and plant cells

Types of prokaryotes

Bacteria and Archaea

Number of chromosomes in prokaryotes

1

Genetic recombination of prokaryotes

Unidirectional transfer of DNA

Genetic recombination of eukaryotes

Meiosis and fusion of gametes

flagella in prokaryotes

submicroscopic; simple

Flagella in eukaryotes

microscopic; complex

True membrane bound nucleus

Eukaryotes

Cell that does not have nucleolus

prokaryotes

Mistosis does not occur here

prokaryotes

DNA complexed with histones

eukaryotes

Does not have chloroplast and mitochondrion

prokaryotes

Plasma membrane with sterol

eukaryotes

Contains organelles

eukaryotes

Basic parts of anima cell

Plasma membrane, cytoplasm, nucleus

Plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Dynamic role of plasma membrane

Encloses cell, supports cell contents, plays a role in communication between cells

Composition of Plasma membrane

phospholipid bilayer, membrane proteins, chrolesterol, glycocalyx

What does plasma membrane separate?

Intracellular substances from extracellular substances

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Composition of cytoplasm

Cytosol, cytoskeleton, cytoplasmic inclusions, cytoplasmic organelles

Function of cytoskeleton

Helps cell maintain shape and helps the cell move; supports the cell and enables movements

Composition of cytoskeleton

microtubules, intermediate filaments, actin filaments

Organelles

Specialized subcellular structures with specific fucntions

Membranous organelles

Mitochondria, peroxisomes, lysosomes, endoplasmic reticulum, and Golgi apparatus

Non-membranous organelles

centrioles, ribosomes

Mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

Where does mitochondria inherited?

Mothers (egg cells)

Mitochondria has

Own DNA

Endosymbiotic theory

suggests engulfed prokaryotes provided hosts with advantages associated with specialized metabolic activities

Lysosomes

Spherical membranous bags containing digestive enzymes

1st function of lysosomes

Digest ingested bacteria, viruses, and toxins

2nd function of lysosomes

Degrade nonfunctional organelles

3rd function of lysosomes

Breakdown glycogen and release thyroid hormone

4th function of lysosomes

Breakdown non-useful tissue

5th function of lysosomes

Breakdown bone to release Ca2+

6th function of lysosomes

Secretory lysosomes are found in white blood cells, immune cells, and melanocytes

1st action of lysosomes

A vesicle forms around material outside the cell

2nd action of lysosomes

The vesicle is pinched off from the plasma membrane and becomes a separate vesicle inside the cell

3rd action of lysosomes

A lysosome is pinched off the Golgi apparatus

4th action of lysosomes

The lysosome fuses with the vesicle

5th action of lysosomes

The enzymes from the lysosome mixes with the material in vesicle, and the enzymes digest the material

Peroxisomes

Membranous sacs containing oxidases and catalases

1st function of peroxisomes

Breakdown fatty acids, amino acids, and hydrogen peroxide

2nd function of peroxisomes

Detoxify harmful or toxic substances

3rd function of peroxisomes

Neutralize dangerous free radicals

4th function of peroxisomes

Free radicals: highly reactive chemicals with unpaired electrons (i.e., O2-)

Endoplasmic Reticulum (ER)

Series of membranes forming sacs and tubules that extend from the outer nuclear membrane into the cytoplasm

2 varieties of Endoplasmic Reticulum

Rough ER and Smooth ER

Rough Endoplasmic Reticulum

Studded with ribosomes; major site of protein synthesis

Smooth Endoplasmic Reticulum

Does not have ribosomes attached; Major site of lipid and carbohydrate synthesis

Golgi Apparatus

Series of closely packed membranous sacs that collect, package, and distribute proteins and lipids produced by the ER

Secretory vesicles

small, membrane-bound sacs that transport material from the Golgi apparatus to the exterior of the cell

Ribosomes

site of protein synthesis

Free ribosomes

not attached to any organelles; synthesize proteins used inside the cell

Attached ribosomes

part of a network of membranes called the rough endoplasmic reticulum (RER); produce proteins that are secreted from the cell

Centrioles

cylindrical organelles located in the centrosome

Functions of centrioles

Help coordinate cell division; the site of microtubule formation

Spindle fibers

microtubules that extend out in all directions from the centrosome; involved in the separation of chromosomes during cell division

Nucleus

Control center of the cell; Contains DNA which contains the coded instructions for making proteins which are the molecules that do "everything"

Parts of nucleus

Nuclear envelope, nucleoplasm, nucleoli, chromosomes (chromatin)

Phases of cell cycle

interphase and mitotic phase

Interphase

Normal cell activity; DNA is replicated along with organelles and other cellular components and the cell prepares for division

Mitotic phase

Cell division

1st Function of Cell Division

Reproduction

2nd Function of Cell Division

Growth and Development

3rd Function of Cell Division

Tissue Renewal

Cell Division

An integral part of the cell cycle; Results in genetically identical daughter cells

Phases of Cell cycle

1. Interphase (G1, S, G2)

2. Mitosis (PMAT)

3. Cytokinesis (cell division)

G0 and G1 Phase

Cell performs its normal function (cells which do not divide stay in this stage for their entire life span)

S Phase

Cell actively duplicates its DNA in preparation for division; Maturation of Daughter centrioles

Where does centriole reproduction begin?

S Phase

G2 Phase

Amount of cytoplasm (including organelles) increases in preparation for division

M Phase

Actual Division occurs

Mitosis

part of eukaryotic cell division during which the cell nucleus divides

What happens in mitosis (1)

They have their DNA "packaged" in the form of Chromosomes

What happens in mitosis (2)

Chromosomes are composed of Chromatin: Made of DNA Strands & Proteins

What happens in mitosis (3)

Also contain Nucleosomes containing Histones - Proteins the DNA is wrapped around Name for the DNA/Protein complex is Chromatin

What happens in mitosis (4)

They usually have more than 1 chromosome (Humans have 23pairs)

What happens in mitosis (5)

They have numerous organelles to equally share

Stages of Mitosis

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

Prophase

Chromosomes shorten and become visible, centrioles move to the opposite sides, nuclear envelope disappear, spindle fibers and astral fibers begin to form

Metaphase

Chromosomes line up in the middle of the cell, chromosomes attach to spindle fibers, spindle fiber and astral fibers are now clearly visible

Name when chromosomes line up along center of cell

Metaphase Plate

Anaphase

Centromeres break up, chromosomes pull apart to the opposite sides, spindle fibers and astral fibers begin to break down.

Telophase

Nuclear envelope forms around both sets of chromosomes, DNA uncoils, Spindle and astral fibers completely disappear

Cytokinesis

Actual splitting of the daughter cells into two separate cells, cytoplasm & organelles move to either side of the cell, cell membrane "pinches" to form 2 separate cells

Mitosis produces?

2 identical daughter cells (diploid cells)

Sexual reproduction

A life cycle is the generation-to-generation sequence of stages in the reproductive history of an organism

Sex cells

Unlike somatic cells, sperm and egg cells are haploid cells, containing only one set of chromosomes

Gametes

At sexual maturity the ovaries and testes produce haploid gametes by meiosis

Diploid

Normal amount of genetic material