Biology - Chapter 3

Scanning electron microscopes

Beam electrons over a metal-coated specimen

Scanning electron microscopes

Bounce electrons off the outside of a metal-coated three-dimensional object to observe the exterior texture

Eukarya

Key genetic sequences suggest that archaea are more closely related to members of domain _________ than they are to members of domain bacteria

Less surface area relative to volume

Less efficient exchange of materials between cell's interior and exterior Large cell sizr

Cell membrane

Lipid-rich boundary between the cells and outside environment

Smooth endoplasmic reticulum

Lipids, detoxifying enzymes, and membrane components are produced and stored in the ______ ____________ ___________

Cell parts in the endomembrane system

Lysosomes; Golgi apparatus; nuclear envelope; endoplasmic reticulum

Microtubules

Main component of the cytoskeleton which is composed of tubulin protein subunits and is used in cell division and transportation within cells

Vesciles

Membranous spheres that transport materials inside the cell as part of the endomembrane system

More surface area relative to volume

More efficient exchange of materials between cell's interior and exterior Small cell size

Mitochondrion

Cellular respiration extracts energy from food and takes place in the organelle called a(n)

Animal crll

Centrioles present; chloroplasts absent

Gap junctions

Channels for the exchange of substances between adjacent animal cells

Nucleolus

Dense spot in the nucleus where components of RIBOSOMES are assembled

Membrane lipids; key genetic sequences

Differences between domains Bacteria and Archaea

Food vacuole in amoebas

Digest nutrients engulfed by cell

Cell membranes

Enclose organelles in eukaryotic cells; separate cytoplasm and cell's surroundings; receive and respond to external stimuli

Organelles; cytoskeleton; ions and enzymes

Found in the cytoplasm, outside the nuclear membrane.

Amoebas have extensions of their cell membrane Red blood cells have a flattened and thin shape Nerve cells are long and thin

How do cells increase their ratio of surface area to volume?

DNA; proteins

In a cell, ___ is the genetic information of the cell, and RNA plays a role in the production of ________

Tight junctions

In animal cells, cell junctions called _____ ________ form barriers between cells that prevent leaking of fluids and water-soluble molecules

Nucleus

In eukaryotic cells, the DNA that specifies the proteins of the cell is stored in a membrane-bounded organelle called thr

3 components of the cell theiry

1. The cell is the fundamental unit of all life 2. All organisms are made of one or more cells 3. All cells originate from preexisting cells

Nucleoid

In prokaryotic cells, DNA congregates in an area called the

nucleus

A eukaryotic cell is different from a prokaryotic cell in that it contains a _______

O2 and CO2, small nonpolar molecules, and lipids

Able to pass freely through the phospholipid bilayer

Cytoplasm

All cell contents except the nucleus

Membrane

All cells have a cell ________ surrounding the cytoplasm and forming a boundary between the cell and its environment

Outside environment

All cells surrounded by cell membranes, also called plasma membranes, that separate the cytoplasm from the

Large leaves in a light-poor environment Large surface area in fish gills

In what cases us high surface area advantageous to an organism?

Cells

All living things consist of one or more _____

Bacteria

Small cell size, fatty acids in the cell membrane, cell wall present in most

Archaea

Small cell size, nonfatty acid lipids in the cell membrane, cell wall present in most

Larger than

Small objects have a surface area to volume ratio _________ ______ that of large objects

Endoplasmic reticulum

Network of membranes originating at the nuclear envelope and wining through the crll

Cytoskeleton

Network of proteins that provide a structural framework within the cell 3 types of protein filaments comprise THIS

Cytoskeleton

Network of proteins that provide a structural framework within the crll

Chloroplasy

Organelle that is the site of photosynthesis in plant cells. A type of plastid.

Membranes

Organelles carry out specialized functions in the cell and are enclosed by _________

Mitochondria and chloroplasts

Organelles that are thought to have arisen by endosymbiosis

Peroxisomes

Organelles that originate in the ER and contain enzymes that dispose of toxic substances

Transmission electron microscopes

Pass electrons through a specimen

Light microscope

Passes light through a transparent or thinly sliced specimen to generate true-color views of cells

Hydrophilic

Phosphate end of a phospholipid, meaning its polar covalent binds attract water.

Transport vesicles

Pinched off the Golgi apparatus and will deliver their contents to another part of the crll

Vacuoles

Plant cells have large central ________ where water, salts, and sugars are stored and where materials are broken down and recycled with enzymes similar to lysosomes in animal cells.

Drawbacks of electron microscopy

Specimens must be killed prior to viewing them The microscopes are expensive All images are black and white

Eukarya

Possible larger cell size, fatty acids in the cell membrane, cell wall present in some

Cell theory

States that all life is composed of one or more cells, which are the fundamental units of all life

Cytoskeleton functions

Structural support; transportation; aids cell division

Ribosome on the rough ER

Proteins become part of the cell membrane or are secreted from the cell

Free-floating ribosome

Proteins remain in the crll

Components of cell membranes

Proteins, phospholipids, steroids

Contractile vacuole in Paramecium

Pump excess water out of the cell

True

T/F Almost all cells have a small size less than 0.1mm in diameter

Hydrophobic

Tails of a phospholipid, face away from the water.

Cell

Simplest and most basic unit of life and can function as one or many working together

Prokaryotic cells

Simplest forms of life and lack a nucleus

Ribosome

Site of protein production

Nucleoid

The area within the cytoplasm of a prokaryotic cell where the circular DBA molecule is found is called the ________ and is not bounded by a membrane

Phospholipid

The cell membrane is composed of a type of lipid called THIS. Has 2 fatty acids and a phosphate group extending from a glycerol molecule.

Ribosome

The cell structure that manufactures proteins

Enzymes

The digestive _______ that end up inside lysosomes are made in the rough ER, and then the Golgi Apparatus packages them into vesicles, forming lysosomes.

Endomembrane

The internal membranes of several organelles are interconnected and form the ______________ system of a eukaryotic cell

Cilia

The paramecium is able to move through its watery environment with the thousands of _____ on the outside of its body.

Cell wall

The rigid ____ ____ of most bacterial cells surrounds the cell membrane, protecting the cell and giving the cell shape

Plastids (plant organelles)

They contain their own DNA and ribosomes Some assemble and store starch Some, such as chloroplasts, synthesize pigmentd

Confocal microscope

White or laser light is focused through a lens, and the image passes through a pinhole

Anchoring junctions

Connect adjacent animal cells by linking their intermediate filaments in one place, like "spot welds"

Anchoring junctions

Connect animal cells to the extra cellular matrix or to adjacent animal cells in one place

Central vacuole in plants

Contains enzymes, salts, pigments, sugars, and acids

DNA

Contains genetic information

Plasmodesmata

Cytoplasm can flow between adjacent plant cells through special openings in the cell wall called ____________

Present in all types of both prokaryotic and eukaryotic cells

Cytoplasm, RNA, ribosomes, DNA

Steps for making a membrane protein for a eukaryotic cell

1. In the nucleus, genes in the DNA encode the membrane protein are copied into a messenger RNA (mRNA). 2. The mRNA exits the nucleus through nuclear pores of the nuclear envelope. 3. The mRNA binds to a ribosome of the rough ER and produces a protein, which exits the ER in a vesicle. 4. The vesicle delivers the protein to the Golgi apparatus, where the protein folds and is packaged in a vesicle for export from the cell. 5. The vesicle fuses with the cell membrane and releases the protein into the membrane surface

Small; large

A ______ cell can exchange materials with the environment more efficiently than a ______ cell can

Plant cell

Chloroplasts present; central vacuole present

Mitochondrion

Functions in the production of cellular energy

Impart shape; prevent the cell from bursting; regulate cell volume

Functions of the cell wall

Tight junctions

Fuse cell membranes of adjacent animal cells, forming a barrier

Bacteria; plants; archaea; fungi; algae

Groups have cells with cell walls

Bacteria

Important decomposers and producers; some live in human intestines and help with digestion; earth's oldest organisms; some are used to make pharmaceuticals

Plasmodesmata

Tunnels for the exchange of substances between adjacent plant cells