Cells

Which ration limits the size of cells?

Surface Area to Volume

What ration limits the size of cells?

Surface Area to Volume.

Which of the following is a feature of exocytosis but not endocytosis? Shape Changes Vesicle Formation Use of ATP Secretion

- 'Exo-' means 'out of' and 'endo-' means 'into'. 'Cyto' refers to the cell. Both process occur at the cell membrane, require vesicle formation and (because the process requires energy) use ATP. Only exocytosis involves secretion-endocytosis is used for absorption.

During endocytosis, what change will most likely occur in the plasma membrane of a cell?

Decreases in size, pinches to surround stuff entering the cell

What are organelles?

Specialized structures within a cell.

State the typical size of a bacterium

1 micrometer

State the typical size of an average eukaryotic cell

100 micrometers

The width of a human hair is 0.1mm. What is the width in um?

100um

A student observes and draws an Amoeba, using the high power lens of a microscope. The diameter of the drawing is 100mm. The actual diameter of the Amoeba is 100 um. What is the magnification of the drawing?

10^3

If a red blood cell has a diameter of 8um and a student shows it with a diameter of 40mm in a cell drawing, what is the magnification of the drawing.

5000

An electron micrograph of a cell, ribosomes, pili and a single circular chromosome are observed. What other structure is likely to be present?

A plasmid

Potassium can move across the membrane by passive or active transport. Distinguish between active transport and facilitated diffusion of ions.

Active transport: required ATP, moves against the gradient (low to high) Facilitated diffusion: diffusion (high to low) but goes through various channels

Describe the process of exocytosis.

Allows to leave cell Protein made by ribosome Exits ER, enters golgi (cis side) Modified in golgi, exits (trans side) Vesicle fuses w/membrane Ex. Pancreas: insulin

Explain the importance of the surface area to volume ratio in limiting cell size.

As the cell grows bigger, the surface area decreases because it has to eat more and the volume increases faster than the surface area can grow. Surface area must be large enough to compensate for volume (ex. bring in needed materials, get rid of waste)

What pair of features is correct for both plant and prokaryotic cells?

Cell membrane, cytoplasm, contains DNA

Which of the following features is/are present in mitochondria but NOT in chloroplasts?

DNA and ribosomes, cristae

During endocytosis, what change will most likely occur in the plasma membrane of a cell?

Decreases in size, pinches to surround stuff entering the cell.

Outline the differentiation of cells in a multicellular organism.

Differentiation-How cells become different (some cells become skin cells or muscle cells, etc.). Page 15. Every cell in your body has instructions to become any cell, but only becomes a certain cell because only a certain part of the DNA is expressed. (Cell to cell communication)

In what way are eukaryotic chromosomes different from prokaryotic chromosomes?

Eukaryotic chromosomes- in nucleus, histones Prokaryotic chromosomes- in a ring shape, in cytoplasm

What is facilitated diffusion?

Facilitated diffusion is a type of passive transport that allows substances to cross membranes with the assistance of special transport proteins.

What is facilitated diffusion?

Facilitated diffusion is a type of passive transport that allows substances to cross membranes with the assistance of special transport proteins. (Goes through channels- difference from simple diffusion)

Which organelles have a transport function?

Golgi Apparatus, Endoplasmic Reticulum

Where in the cell would the protein be located?

In the phospholipid bilayer In middle, lodged, integral,

Which of the following structures are present in BOTH plant and animal cells? I. Cell Wall II. Chloroplast III. Mitchondrian

Mitochondrion

What is the function of the golgi apparatus?

Packaging proteins

Distinguish between the structure of plant and animal cells.

Plant cells: Have cell walls, chloroplasts, large central vacuole, stiff and rectangular Animal cells: Multiple vacuoles, centrosome, only a cell membrane, no chloroplasts, round and fluid

What is the function of the rough endoplasmatic reticulum?

Protein synthesis

Which two molecules are the principal components of membranes?

Proteins, lipids

Distinguish between the terms resolution and magnification when applied to electron microscopy.

Resolution: How clear it is Magnification: how big it is

What characteristic is correct for the cellular process of exocytosis?

Secretion of cellular materials.

Which of the following is required for osmosis to occur?

Semipermeable membrane, concentration gradient

Which of the following is required for osmosis to occur?

Semipermeable membrane, concentration gradient, aqua pores to help water come in (not required but helps it)

Define the term diffusion.

The movement of molecules from an area of high concentration to an area of low concentration.

What characteristic is correct for the cellular process of endocytosis?

Vesicles are moved away from the plasma membrane.

Which combination of organelles is found in most plant and animal cells?

all organelles are present in both types of cells except for cell wall and chloroplasts found in plant cell.

State one type of secondary structure of a protein.

alpha helix OR beta pleated

What is essential for diffusion?

change in solute concentration (gradient)

macromolecules are being transported to the exterior of a cell. What is the name of this process?

exocytosis

globular

fibers all mixed up, soluble in water, have rounded shape, tertiary structure, immunoglobulin / hemoglobin /catalase / named enzyme /other globular protein;

Which of the following is a characteristic of organelles?

found in both eukaryotic and prokaryotic cells (Membrane-bound organelles are only found in eukaryotes)

List the functions of membrane proteins.

hormone binding sites; enzymatic action; cell adhesion; cell to cell communication; channels for passive transport; pumps for active transport.

List two functions of membrane proteins.

hormone functions, enzymatic action

Formulas to know

mm = 10^-3 UM = 10^-6 NM = 10^-9

fibrous proteins

nicely wrapped around, have a long and narrow shape, mostly insoluble in water, secondary structure, collagen / myosin / silk / keratin / other fibrous protein