Cell Quiz

Cell Theory

Cell Theory

all living things are composed of cells; cells are the basic units of structure and function in living things; new cells are produced from existing cells

Who created the cell Theory?

Schleiden, Schwann, and Virchow

Prokaryotic cells

cells that have no nucleus and membrane-bound organelles; smaller and simpler than eukaryotic cells; ex: bacteria

Eukaryotic cells

cells that have a nucleus (containing DNA) and dozens of structures and internal membrane-bound organelles; gernerally larger and more complex than the other cells; most are highly specialized; ex: plants, animals, fungi, and protists

All cells

surrounded by a barrier called a cell membrane, have DNA, and classified based on whether they have a nucleus

Organelles

structures that have important functions

nucleus

contains most of the cell’s DNA (genetic material)

nucleolus

it produces a type of RNA, ribosomal RNA, and joins rRNA with proteins to form the subunits of ribosomes

nuclear envelope

it has nuclear pores to permit the passage of ribosomal subunits and mRNA out of the nucleus and into the cytoplasm and the passage of proteins from the cytoplasm into the nucleus

Genetic Material (DNA or chromatin)

diffuse threads containing DNA and protein and controls the development of, maintenance, and reproduction of organisms

ribosomes

makes proteins; are small particles of RNA and protein found throughout the cytoplasm

Endoplasmic Reticulum

assembly area for lipids, proteins, and some other materials that are exported from the cell; smooth/rough

Rough ER

studded with ribosomes and synthesizes and modifies proteins

Smooth ER

lacks ribosomes, synthesizes lipid molecules, and forms vesicles that transport molecules to other parts of the cell

Golgi Apparatus

modifies, sorts, and packages proteins and other materials

Lysosomes

small organelles filled with enzymes; breaks down lipids and carbohydrates; also breaks down organelles that have outlived their usefulness

Vacuoles

stores materials such as water, salts, proteins, and carbohydrates

Vesicles

cellular packages containing products such as protein

Mitochondria

converts the energy stored in food into energy the cell can use; site of cellular respiration

Chloroplasts

captures energy from sunlight and converts it into energy the cell can use (photosynthesis); contains the green pigment chlorophyll

Cytoskeleton

gives shape and internal organization to eukaryotic cells; made up of microfilaments and microtubules

centrioles

organize microtubules that serve as the cell’s skeletal system; located inthe cytoplasm of an animal cell near the nuclear envelope; determine the locations of the nucleus and other organelles within the cell

What do prokaryotic cells have?

no nucleus, less features/organelles (no membrane-bound organelles), unicellular, less complexity, usually smaller, and ex: Bacteria

What do eukaryotic cells have?

have a nucleus, has membrane-bound organelles, multicellular, more complex, usually bigger, cell specialization, and ex: plant, animal, and fungi

All cells have a

cell membrane

Cell Membrane

regulates what enters and leaves the cell, provides protection and support, and made up of a phospholipid bilayer and protein; helps the cell and organism maintain a steady internal environment

Cell Wall

provides support and protection; found in plants, fungi, algae, and some prokaryotes

Every living ____ exists in a _____ environment.

cell; liquid

What is diffusion?

one way things move into and out of the cell

What happens during diffusion?

particles move from high concentration to low concentration until it reaches equilibrium; depends on random particle movement so no energy is needed

Equilibrium

when the concentration of the solute is the same throughout (both sides of the cell)

Osmosis

the diffusion of water through a selectively permeable membrane; water moves from high concentration to low concentration

Isotonic

when the concentration of water and solute are the same on both sides of a membrane

Hypertonic

when there is more solute than water

Hypotonic

when there is less solute than water

What pressure does osmosis exert?

Osmotic pressure

In order to survive, organisms need a way to balance the ______ and ______ of water

intake; loss

Cell membranes have _____ ________ which allow certain molecules to cross easily

protein channels

Facilitated diffusion

proteins help some particles move across a membrane; is fast and specific (due to protein structure); only occurs if there is a concentration gradient (high on one side, low on the other)

Passive Transport

moves particles (molecules and ions) across the membrane with the concentration gradient (high to low); does not require energy

Active Transport

mvoes particles against the concentration gradient (low to high); requires energy (ATP); small molecules and ions are carried across by proteins in the membrane

Endocytosis

process of taking things into the cell by infoldings of the cell membrane; the pocket then breaks free of the membrane and forms a vacuole inside the cell; ex: phagocytosis and pinocytosis

Phagocytosis

taking in large amounts of solid material; “cell eating“

Pinocytosis

taking in large amounts of liquid; “cell drinking”

What color does a substance or solution turn into when starches are present after being tested by iodine?

blue-black

What color does a substance or solution turn into when glucose is present after being tested by Benedict’s Reagent?

green, yellow, yellow-orange, orange, orange-red, red

Unicellular

organisms made up of only one cell

Multicellular

organisms made up of many cells; a great variety among these organisms

What is cell specialization?

(only in Eukaryotic cells) cell throughout an organisms can develop in different ways to perform different tasks; anial cells are specialized in many ways

What are the four levels of organization in a multicellular organism?

individual cells, tissues, organs, organ system

tissues

a group of similar cells that perform a particular function

organs

groups of tissues that work together to perform a specific function

organ system

a group of organs that work in systems; they come together to make up an organism

Plant cells vs. Animal cells

plant cells: chloroplasts, a large permanent central vacuole, and a cell wall

animal cells: lysosomes, centrioles, temporary vacuoles, and vesicle

Tonicity

the ability of a solution surrounding a cell to cause that cell to gain or lose water; strength of the solution

Hypotonic in Elodea Cells

chloroplasts are moving; pressed against the cell wall

In a ____ solution, the central vacuole of a plant exerts _______, and the chloroplasts are seen up against the cell wall.

hypotonic; tugor pressure; pushed

Hypertonic in Elodea Cells

chloroplasts are at the middl eof the cell, not moving, and bunching together

In a _____ solution, the central vacuole ____ water, and the cytoplasm including the chloroplasts have ______ away from the cell wall.

hypertonic; loses; pulled

The Sandwhich Model

the phospholipid bilayer filled between two continuous layers of proteins plus the hydrophilic heads and hydrophobic tails of the phospholipids

Unite Membrane Model

all membranes in various cells have basically the same composition

Fluid-Mosaic Model

the membrane is a fluid phospholipid bilayer in which protein molecules are either partially or wholly embedded; proteins form a mosaic pattern

Phospholipid

a molecule that has both a hydrophilic region and a hydrophobic region; hydrophilic polar heads face the outside and the insde of the cell, where water is found; hydrophobic nonpolar tails face each other

Cholesterol

another lipid found in animal plasma membrane; related steroids are found in the plasma membrane of plants; it stiffens and strengthens the membrane, helping regulate its fluidity

Proteins in a membrane can be ______ proteins or ______ proteins

peripheral; integral

Peripheral proteins

when they are on the inside surface of the membrane, they are often held in place by cytoskeletal filaments

Integral proteins

embedded in the membrane, but can move laterally back and forth; can protrude from only one surface of the bilayer; span the membrane, with a hydrophobic region within the membrane and hydrophilic regions that protrude from both surfaces of the bilayer (transmembrane proteins)

Both phospholipids and proteins can have attached carbohydrate (sugar) chains, ______ and _____ respectively

glycolipids; glycoproteins

Two sides of the membrane are not

identical

Glycocalyx

carbohydrate chains of proteins as a “sugar coat” ove a cell; protects the cell and has various other functions

Carbohydrate chains can vary greatly by the _____ and ___ of sugars and by whether the chain is ________

number; sequence; branched

Lipid components

they decide the fluidity fo the membrane which is critical to its proper functioning

The ____ the concentration of unsaturated fatty acid residue, the ____ more fluid is in hte bilayer which increases the membrane’s fluidity

great; more

Can the proteins not held in palce by cytoskeleton drift laterally in the fluid lipid bilayer?

yes

A membrane’s fluidity is needed for some

protein’s function (ex. enzymes)

Enzymes are _____ when membranes are solidified

inactive

Plasma membranes of various cells and the membranes of various organelles each have…

their own unique collections of proteins that form different patterns according to the particular membrane and also within the same membrane at different times

Integral proteins examples

channel proteins, carrier proteins, cell recognition proteins, receptor proteins, enzymatic proteins

Channel proteins

help move molecules and substances across a membrane

Carrier proteins

combine with a substrate to move it through a membrane

Cell recogition proteins

help the body realize when pathogens are invading so an immune reaction can occur

Receptor proteins

bind to specific molecules which causes a protein ot change shape and bring about a cellular response

Enzymatic proteins

carry out metabolic reactions directly

The peripheral proteins often have a _____ role in that they help ____ and _______ the plasma membrane

structural; stabilize; shape