Campbell Biology 12th Edition: Chapter 6

cells

all organisms are made of cells

simplest unit of life

all cells are related by their descent from earlier cells

microscopic/ measured in micrometers

Microscope

used to visualize cells

Important parameters of microscopy

Magnification

Resolution

Contrast

Types of Microscopes

Light Microscope

Electron Microscopes

Fluorescent Microscope

Confocal Microscope

Light Microscope

aka Bright Field microscope or Light compound microscope

-uses white bulb

-not great resolution

-long wavelength

-only resolves items 0.2 micrometers away or more

- keeps cell alive

Types of Electron Microscopes

Scanning electron microscopes (SEMs)

Transmission electron microscope (TEMs)

Scanning electron Microscopes

scan outside of the cell;

electrons bounce off surface and produce image; kills cell

Transmission electron Microscopes

capture inside of cell;

make a thin slice so electrons can enter cell to take picture; kills cell

Fluorescent Microscope

- uses UV light

- shorter wavelength

- better resolution

-add fluoresce to cell or use natural

Confocal Microscope

- add fluoresce to part of cell

- 3D image

Cell Fractionation

centrifuge machine break apart cells into their different components

Basic cell features

Plasma membrane/ Cell membrane

Cytosol

Chromosomes

Ribosomes

Eukaryotic Cells

Kingdom Protista, fungi, Animalia, plantae

- a nucleus

- membrane bound organells

- cytoplasm: area within membrane including all organells/ stops at nuclear envelope

- larger

- selectively permeable membrane

Prokaryotic Cells

Domain Bacteria and Archaea

- no nucleus

- nucleoid

- no membrane bound organells

- cytoplasm: cytosol within membrane, including all the organells

-selectively permeable membrane

-evolved 3.8 billion years ago

Single cell vs. Multicell organisms

- more cells= more cell surface

- more cell surface= more metabolism

- single cell dies= organism dies

Phospholipids/ Lipids in cells

the basic fabric of biological membrane

organells

have their own specific job to complete for cell survival

Nuclear envelope

made of a double membrane (phospholipid bilayer)

Nucleus

- holds the DNA

- has nuclear pores

- nuclear envelope

- nucleolus

- chromatin

- chromosomes

- nuclear lamina

Nuclear pores

- pores in the nuclear envelope

- DNA cant leave the nucleus

- RNA can leave nucleus out of pores

nuclear lamina

protein layer that lines the inside of the nuclear envelope; maintains nucleus shape

chromatin

DNA associated with proteins; DNA is wrapped around proteins called histones for organization

Chromosomes

When DNA is organized into units; condensed chromatin

Ribosomes

- used for protein synthesis

- made of rRNA (ribosomal RNA) and proteins

- free ribosomes

- bound ribosomes

Free ribosomes

ribosomes within the cytoplasm

- makes proteins used within the cell

Bound ribosomes

ribosomes bound to the ER or Nuclear Envelope

- make proteins that are exported from the cell

Endoplasmic Reticulum (ER)

- membrane bound organelle

- membrane is continuous with nuclear envelope

- smooth ER

- rough ER

Smooth ER

- synthesize lipids

- metabolizes carbohydrates

- detoxifies drugs and poisons

- stores calcium ions

Rough ER

- RNA works its way through to be converted to proteins

- has ribosomes associated with it

- create glycoproteins

- distributes transport vesicles to the Golgi apparatus

- membrane factory for the cell

transport vesicles

secretory proteins surrounded by membranes

glycoproteins

sugar proteins; proteins covalently bonded to carbohydrates

Golgi apparatus

- made of cisternae

- receives/modifies proteins from Rough ER

- sorts/ packages materials into transport vesicles

- manufactures certain macromolecules

- cis face and trans face

cisternae

flat membrane sacks

cis face

receiving side of Golgi Apparatus; towards the Rough ER

trans face

away from Rough ER; exports finalized proteins to different parts in the cell plasma membrane or out of cell

Lysosome

- hydrolytic enzymes

- digest old organells, invaded bacteria, waste

- ingests then breaks down in itself

- if broke, would kill cell (acidic)

- phagocytosis

- autophagy

hydrolytic enzymes

- digest substances

- work in the acidic enviornment inside lysosome

- made by the Rough ER then transferred to Golgi Apparatus for processing

phagocytosis

the act of a lysosome merging with material then lytic enzymes digest it

- break down small enough that it is undetectable

autophagy

getting rid of old organelles; combine with organelle then digests it

vacuoles

-derived from ER and Golgi Apparatus

three types of vacuoles

food vacuole

contractile vacuole

central vacuole

food vacuole

circular portions of the plasma membrane that capture or encircle food particles when they enter the cell

contractile vacuole

- found in Protista kingdom

- found in animals that live in water

- contract and squeeze out water

central vacuole

- found in plants

- holds water, organic compounds

- storage tank

mitochondria

-powerhouse of the cell

- found in all eukaryotic cells

- double membrane

- metabolism occurs/ cellular respiration

- ATP energy carrier

mitochondria double membrane

- cristae

- inner membrane/ outer membrane

- intermembrane space

mitochondrial matrix

cristae

folding in the inner membrane; creates more surface area for more cellular respiration

intermembrane space

space between two membranes in mitochondria

mitochondrial matrix

space within the second membrane; holds ribosomes

Chloroplasts

- found in photosynthetic organisms (plants, protists...)

- chlorophyll

- thylakoids

- stroma

- group plastids

- double membrane (flat)

chlorophyll

- main pigment group in chloroplasts (green); requires sunlight

thylakoids

membrane sacks; holds chlorophyll

granum

a stack of thylakoids

stroma

the internal fluid in chloroplasts

Peroxisome

- Oxidative organells

- Break down harmful bi products to prevent cell death

- Contain enzymes to break down inner toxins

catalase

enzyme in peroxisomes; takes hydrogen peroxide then breaks it down to water

endosymbiotic theory

a large prokaryotic cell adapted eukaryotic features; then engulfed another prokaryotic cell; evolved into eukaryotic cell

cytoskeleton

- support system in cells

- Fibers that are within the cytoplasm

-supports the cell

-anchors organells

- Act as a train track to transport organells from one location in cell to another

- Helps with replication

- Interacts with motor proteins to produce cell motility

three types of cytoskeleton

Microtubules

Microfilaments

Intermediate filaments

Microtubules

- made of protein tubulin

- largest cytoskeleton

- shapes the cell

- guide movement of organells

- separate chromosomes during cell division

centrosome

reigon in animal cells where microtubules are formed

- near nucleus

- made of centrioles

centrioles

9 triplets to form a star shape; in microtubules

cilia

shorter extensions off of the cell; can wave back and forth; move substances along its surface; made of microtubules

Flagella

used for movement; made of microtubules

Basal body

part that anchors cilia or flagella to cell; 9 pairs of triplets

-Top parts have different pattern doublets + 2 in center

Microfilaments

(actin filaments)

- smallest cytoskeleton

- made of protein actin

- gives support

- form a cortex inside cell for support

- make microvilli

microfilaments that function in motility

have protein myosin and actin

microvilli

- small fingers; made of microfilaments

- increase surface area

- help with absorption

- help with movement/ motility

- made of microfilaments

pseudopodia

cellular extensions; enable cells to crawl along a surface and extending toward objects

cytoplasmic streaming

a circular flow of cytoplasm within cells driven by actin-myosin interactions

Intermediate filaments

- intermediate cytoskeleton

- more permanent

- support cell shape and fix organells in place

extracellular components

features outside the plasma membrane

Plant Cell Walls

- extracellular component

- prokaryotes, fungi, unicellular eukaryotes (Protista)

- maintains shape

- protection

- prevents excess uptake of water

- made of cellulose from polysaccharides and proteins

- permeable to water and small solutes

Parts of cell wall

primary cell wall

middle lamella

secondary cell wall

primary cell wall

thin and more flexible

middle lamella

the layer between the primary and any adjacent cells

secondary cell wall

(only in some cells) between the plasma membrane and the primary cell wall

Extracellular Matrix (EMC) of Animal Cells

- What the cells are floating in

-Made up of glycoprotein (like collagen), proteoglycans, and fibronectin

- ECM proteins bind to integrins

- regulate behavior

- Influence the activity of gene in the nucleus

- involved in Mechanical signaling

mechanical signaling

cytoskeleton change triggers chemical signals to change

integrins

receptor proteins in the plasma membrane; name tags of cells; bind to ECM

- regulate cell's behavior through integrin communication

Cell Junction

Neighboring cells in tissues, organs, or organ systems often adhere, interact and communicate through direct physical contact

Plasmodesmata

type of junction in plant cell

types of cell junctions

Tight junction

Desmosomes

Gap junction

Tight junction

closely knit bonding; nothing can pass; no opening; not a lot of movement

Desmosomes

want to be bound; yet more movement occuring; bind and move without tear

Gap junction

has a passageway; transport materials from one cell to another