Biology Ch 1

kaplan biology book 26-27

What is the cell theory?

1. All living things are composed of cells

2. the cell is the basic functional unit of life

3. cells arise only from preexisiting cells

4. cells carry genetic information in the form of DNA, this genetic material is passed on from parent to daughter cell.

What do eukaryotic cells contain?

a true nucleus in an enclosed membrane and membrane-bound organelles.

Cytosol allows for what?

the diffusion of molecules throughout the cell

What does the nucleus contain?

• it contains all the genetic material necessary for replication.

• its surrounded by a nuclear membrane (distinct from cytoplasm)

• nuculear pores allow 2 way exchange between pores and cytoplasm

• DNA contains coding region called genes.

What is nucleolus?

• subsection of the nucleus

• is where ribosomal DNA is synthesized

• takes up 25% of the volume of nucleus (darker spot)

What is the mitochondria?

• 2 layers ; inner and outer membrane

• outer membrane is a barrier between cytosol and inner mito.

• capable of killing the cell by release of enzymes from ETC which starts apoptosis (cell death)

Inner membrane of mitochondria

• arranged into infoldings called cristae that contain molecules and enzymes of the ETC.

• cristae increases surface area for ETC enzymes

What is the space inside the inner membrane of the mitochondria called?

mitochondrial matrix

what happens in the mitochondrial matrix?

• The pumping of protons from the mitochondrial matrix to the inner membrane space establishes the proton motive force; protons flow through ATP synthase to generate ATP during oxidative phosphorylation.

What is extranuclear inheritance?

contain some of their own genes and replicate independently of the nucleus via binary fission.

What are lysosomes?

membrane-bound structures containing hydrolytic enzymes that can break down many substrates.

• function in conjunction with endosomes.

What are endosomes?

They transport materials to trans-golgi to the cell membrane or the lysosomal pathway for degradation.

Apoptosis

When lysosomes release hydrolytic enzymes.

Rough endoplasmic reticulum (RER)

• studded with ribosomes

• permit translation of proteins into its lumen

Smooth ER (SER)

• Lacks ribosomes

• used for lipid synthesis and detoxification

• transports proteins from the RER to golgi apparatus.

What is the Golgi Apparatus?

• consists of stacked membrane-bound sacs

• cellular products are modified to carbs, phosphates, sulfates.

• repackaged in vesicles directed to the cellular location.

What happens if products are destined for secretion? (Golgi)

The secretory vesicle merges with the cell membrane, and its contents are released. (exocytosis)

What are peroxisomes?

• breakdown long-chain fatty acids via 𝜷-oxidation.

• provides structure to the cell and maintains the shape.

• contains hydrogen peroxide.

What are the 3 components of peroxisomes?

microfilaments

microtubules

intermediate filaments

What are microfilaments?

• made up of solid polymerized rods of actin.

• Actin filaments can use ATP to generate force for movement by interacting with myosin.

What role do microfilaments play in mitosis?

The cleavage furrow is formed from microfilaments and serves as a ring at the site of division for daughter cells.

What are microtubules?

• hollow polymers of tublin protins radiate throughout the cell, provides primary pathway for proteins like kinesin and dynein cary reciles.

• Cilia and flagella, motile structures, are composed of microtubulesb

What are cilia?

invovled in movement of material along the surface of the cell

example of cilia?

cilia line respiratory tract are involved in the movement of the mucus.

what is flagella?

its invovled of the movement of the cell, like sperm cells moving through the reproductive tract.

What are centrioles, and where are they found?

They organize microtubules and are structured as 9 triplets of microtubules with a hollow center. They are found in the centrosome.

What are intermediate filaments?

diverse group of filamentous proteins: iceratin, desmin, vimentin, and lamins.

• involved in cell-cell adhesion or maintenance of the cytoskeleton.

• can withstand tension and increase the structural rigidity of the cell.

What are the 4 types of tissues?

epithelial, connective, muscular, and nervous.

What is an example of tissue formation?

In the heart, some cells participate in the conduction pathways while others cause contractions.

What is epithelial tissue?

• covers the body and lines its cavities, providing protection against pathogen invasion and desiccation.

• In some organs, its invovled in absorption, secretion, and sensation.

• tightly joined together and to an underlying layer of connective tissue known as the basement membrane.

An example of epithelial tissue?

• Nephrons in the kidney are composed of epithelial cells and hepatocytes in the liver, and acid-producing cells in the stomach are epithelial.

Types of epithelial tissue

• simple: has 1 layer of cells

• stratified: has multiple layers

• pseudostratified: appears to have multiple layers due to cell height, but really has 1 layer.

Shapes of epithelial tisse

• cuboidal: cells are cubed shape

• columnar: cells are long and thin

• squamous: cells are flat and cell-like.

What is connective tissue?

• supports the body and provides a framework for the epithelial cells to carry out their functions.

• contributes to the stroma and supports the structure.

What ARE connective tissue?

• bone, cartilage, tendons, ligaments, adipose tissue, and blood.

What is microscopy?

• used to visualize small structures.

What is light microscopy?

uses visible light and lenses to produce an image 200nm or larger.

What is confocal microscopy?

increase optical resolution through the use of a spation pinhole that blocks out focus light to create sharper images.

What is confocal usually paired with?

immunohistochemistry, where antibodies with fluorescent probes are used to label different subcellular components.

electrons in transmission electron microscopy pass through what?

ultrathin sections of a speciman to create an image.

What is fluorescence microscopy?

Any type of microscopy that uses fluorescence as a means of visualization.

What is a prokaryotic cell?

• include all bacteria, no membrane-bound organelles.

• Genetic information is in the nucleoid.

• causes infection

What are the 3 domains for prokaryotic cells?

archaea, bacteria, and eukarya.

What is Archaea?

• single-celled organisms similar to bacteria

• considered extremophiles; isolated from harsh environments with high temp, high salinity, or no light.

• notable for the ability to use alternative sources of energy.

What is bacteria?

• All bacteria contain a cell membrane and cytoplasm, and some have flagella or fimbriae.

• Bacteria and eukaryotes share an analogous structure.

• Some bacteria is mutalisitic symbiotes; they benefit eachother.

Shapes of bacteria

• spherical bacteria

• rod-shaped

• spiral-shaped.

spherical bacteria

• known as cocci include common pathogens like Streptococcus pyogenes.

Rod-shaped bacteria

like escherichia coli (bacili)

Spirial shaped

Ex Treponema pallidum, which causes syphilis.

aerobes

Bacteria that requires oxygen for metabolism is obligate.

Anaerobes

Bacteria that is used for fermentation or other cellular metabolism that doesnt need oxygen.

Faculative anaerobes

Bacteria that can toggle between metabolic processes, using oxygen for aerobic metabolism if it’s present.

aerotolerant anaerobes

can’t use oxygen for metabolism, but aren’t harmed by its presence.

Cell wall of prokaryotic cells

• outer barrier of the cell

• next layer is plasma membrane, which contains phospholipids

• 2 main cell walls, which are gram-positive and gram-negative.