Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

109 Cards in this Set

  • Front
  • Back
  • 3rd side (hint)
Who were the first observers of cell life?

When did modern cell theory emerge?
1. Hooke in 1663:

2. Schwann in 1800’s

3. Pasteur’s work with bacteria in 1860.

Modern cell theory emerged by 1900
One named the cell.

Another disproved idea of spontaneous generation (living things arise from nonliving matter)
What are the principles of Modern Cell Theory?
1. All organisms are composed of cells and cell products.

2. A cell is the simplest structural and functional unit of life.

3. An organism’s structure and all of its functions are ultimately due to the activities of its cells.

4. Cells come only from preexisting cells, not from nonliving matter.

5. Because of this common ancestry, the cells of all species have many fundamental similarities in their chemical composition and metabolic mechanisms.
Five items

There are no smaller subdivisions of a cell or organism that, in themselves, are alive.
Name the differnet types of cell shapes.
1. Squamous - thin, flat, angular

2. Spheroid - round to oval.

3. Polygonal - irregular
angular shapes,
with more than 4 sides.

4. Discoid - disc shaped.

5. Cuboidal -squarish

6. Columnar -taller than wide

7. Fusiform -thick middle with
tapered ends

8. Fibrous - long, slender

9. Stellate - star-shaped
Nine types
What are the limitations on cell size?
As the cell enlarges, volume increases faster than surface area so the need for increased nutrients and waste removal exceeds ability of membrane surface to exchange them
Consisder area to volume ratio
What is the difference between Resolution and Magnification?
An object with the same magnification as another will have increased detail if its resolution is higher.
What are the basic parts of a typical cell?
1. cell membrane

2. nucleus

3. organelles

4. cytoskeleton

5. cytosol (intracellular fluid or ICF)
Five major parts
What is the Plasma Membrane?
1. Defines cell boundaries

2. Controls interactions with other cells

3. Controls passage of materials in and out of cell
3 major functions

What is Cell Adhesion?
Cells have binders and when two cells make contact they stop dividing.
Tumor cells do not have this control.
What is the cell membrane composed of?
An oily film of phospholipids with diverse proteins embedded in it
What are the Membrane Protein Functions?
1. Receptors

2. Second messenger systems

3. Enzymes

4. Channel proteins

5. Carriers

6. Motor molecules

7. Cell-identity markers

8. Cell-adhesion molecules
Eight functions
How does the Receptor and Second-messenger System work?
Cells communicate with chemical signals that cannot enter target cells.

Activation of the receptor may produce a second messenger inside of the cell.
Membrane receptors bind these messengers (hormones, neurotransmitters).

Each receptor is usually specific for one messenger
What do enzymes in the cell do?
1. May break down chemical messengers to stop their signaling effects

2. Produce final stages of starch and protein digestion in small intestine

3. Involved in producing second messengers inside of the cell
Three items
What do Channel Proteins do?
They are Integral proteins that form pores (channels) for passage of water or solutes.

Some channels are constantly open.

Others,Gated-channels, open & close in response to stimuli.
Important in nerve signal and muscle contraction
What are Membrane Carriers or Pumps?
Integral proteins that bind to solutes and transfer them across membrane.

Carriers that consume ATP are called pumps
What are Molecular Motors?
A filamentous protein that arises in the cytoplasm and pulls on membrane proteins causing movement.

Actin and myosin act as molecular motors.
move materials within a cell (organelles)
move whole cells (WBC’s)
change shape of cell during cell division and phagocytosis
What are Cell-Identity Markers?
A surface coating that acts as a cell’s identity tag.

Composed of Glycoproteins.

Enables the body to identify “self” from foreign invaders
What are Cell-Adhesion Molecules?
Membrane proteins that adhere cells together and to extracellular material.
Cells are normally mechanically linked to extracellular material
What are the functions of the Glycocalyx?
1. It enables the immune system to recognize normal cells from transplanted tissue, diseased cells and invading organisms.

2. It cushions and protects the cell membrane.

3. It assists in cell adhesion, fertilization and embryonic development.
What is the function of Microvilli?
They increase the surface area for absorption from 15-40 times.
What are the function of Cilia?
Sensory: in inner ear, retina and nasal cavity

Motile: cilia beat in waves, sequential power strokes followed by recovery strokes
What is a flagella?
A long whiplike structure that has an axoneme identical to that of a cilium.
What can be said about the permiability of the plasma membrane?
The Plasma membrane is selectively permeable.

It controls which things enter or leave the cell.
What is Passive transport?
It requires no ATP

Movement of particles is down their concentration gradient.

Filtration and simple diffusion are examples of passive transport.
What is Active transport?
It transports particles against their concentration gradient.

Carrier mediated (facilitated diffusion and active transport) and vesicular transport are examples of active transport.
What is Filtration?
Movement of particles through a selectively permeable membrane by hydrostatic pressure.
filtration of wastes from the blood occurs in the kidneys
What is Hydrostatic pressure?
The force exerted on the membrane by water.
What is Simple Diffusion?

What is Net diffusion?
Simple diffusion is the movement of particles as a result of their constant, random motion.

Net diffusion is the movement of particles from an area of high concentration to an area of low concentration (down or with the concentration gradient)
What are the factors that affect the rate of diffusion through a membrane?
1. temperature - increased temp = increased motion of particles

2. molecular weight - larger molecules move slower

3. steepness of concentration gradient - an increase in difference = increased rate

4. membrane surface area - increased area = increased rate

5. membrane permeability - increased permeability = increased rate
Five factors
What is Osmosis?
Diffusion of water through a selectively permeable membrane.
What is Osmotic Pressure?
The amount of hydrostatic pressure required to stop osmosis is the osmotic pressure.
What is Tonicity?
The ability of a solution to affect fluid volume and pressure within a cell.
What is a Hypotonic solution?
It has low a concentration of nonpermeating solutes (high water concentration).

Cells in this solution would absorb water, swell and may burst (lyse)
What is a Hypertonic solution?
It has a high concentration of nonpermeating solutes (low water concentration).

Cells in this solution would lose water +shrivel (crenate).
What is Carrier Mediated Transport?

What types are there?
Proteins carry solutes across the cell membrane.

Facilitated diffusion and active transport.
What is Facilitated Diffusion?
Carrier-mediated, passive transport of solute across membrane DOWN its concentration gradient.

No energy is needed.
What is Active Transport?
Carrier-mediated, active transport of solute across membrane AGAINST its concentration gradient.

Energy required. ATP is used.
What is Vesicular Transport?

What are two types?
Transport of large particles or fluid droplets through membrane in bubblelike vesicles of plasma membrane, uses ATP.

Exocytosis – vesicular transport out of cell

Endocytosis – vesicular transport into cell
What are phagocytosis and pinocytosis?
Phagocytosis – engulfing large particles by pseudopods

Pinocytosis – taking in fluid droplets
What are two types of Organelles?
1. surrounded by membrane

2. not surrounded by membrane
Give examples of organelles
surrounded by membranes.
nucleus, mitochondria, lysosome, perioxisome, endoplasmic reticulum, and golgi
Seven items
Give examples of organelles not surrounded by a membrane.
ribosome, centrosome, centriole, basal bodies
What is the Cytoskeleton?
A collection of microfilaments and microtubules in the Cytoplasm.
Describe the Nucleus.
It is the largest organelle (5 m in diameter)

The Nuclear envelope has
two unit membranes held together at nuclear pores
What is contained in the Nucleoplasm?
1. Chromatin - is thread-like matter containing DNA and protein

2. Nucleoli - is dark masse where ribosomes are produced
Describe the Endoplasmic Reticulum.
1. ROUGH ER - is covered with ribosomes, continuous with nuclear envelope -function in protein synthesis and production of cell membranes

2.SMOOTH ER - lacks ribosomes, continuous with rough ER
function in lipid synthesis, detoxification, calcium storage
Two types

Describe the Golgi Complex.
Function: is to refine, package, and deliver proteins which were made on the ribosomes
Packaging unit
What do Golgi vesicles do?
They are irregular sacs near golgi complex that bud off cisternae.

Some become lysosomes, some fuse with plasma membrane and some become secretory vesicles
What are Lysosomes?

What are their functions?
A package of enzymes in a single unit membrane, variable in shape.

1. Intracellular digestion - hydrolyze proteins, nucleic acids, complex carbohydrates, phospholipids and other substrates.

2. Autophagy - the digestion of worn out organelles and mitochondrion.

3. Autolysis - programmed cell death.

4. Glucose mobilization - lysosomes in liver cells break down glycogen.
Four functions
What are Peroxisomes?

What are their functions?
Rhey appear similar to lysosomes but not produced by golgi complex.

In all cells but abundant in liver and kidney.

1. neutralize free radicals.

2. produce H2O2 in process of alcohol detoxification and killing bacteria.

3. break down excess H2O2 with the enzyme catalase.

4. break down fatty acids(lipids).
Four functions
Describe a Mitochondrion.

What is its main function?
It is Double unit membrane

The Inner membrane contains folds called cristae

Space between cristae called the matrix - contains ribosomes and small, circular DNA (mitochondrial DNA)

Reproduce independently of cell and live for 10 days.

ATP is synthesized by enzymes on cristae from energy extracted from organic compounds.
Describe Centrioles.

What is their main function?
Short cylindrical assembly of microtubules, arranged in nine groups of three microtubules each

Two centrioles, perpendicular to each other, lie near the nucleus in an area called the centrosome

these play a role in cell division these play a role in cell division

also form basal bodies of cilia or flagella
What is the Cytoskeleton composed of?
It is a collection of filaments and tubules that provide internal support and movement of cell

Composed of microfilaments, intermediate filaments and microtubules
What is a Microtubule?

What is its function?
Acylinder of 13 parallel strands called protofilaments

Hold organelles in place and maintain cell shape

Form tracks to guide organelles and molecules to specific destinations in a cell
Describe microfilaments and intermediate filaments.
MICROFILAMENTS - form network on cytoplasmic side of plasma membrane called the membrane skeleton

produce cell movement, and with myosin causes muscle contraction

INTERMEDIATE fibers - in junctions that hold epithelial cells together and resist stresses on a cell
Who first named DNA?

What did he believe it was?
named by biochemist Johann Friedrich Miescher (1844-1895) and his student

believed it was heriditary matter of cell, but no real evidence
What is the structure of DNA?

When was it discovered?

Who discovered it?
The double helix


Nobel Prize awarded in 1962 to 3 men: Watson, Crick and Wilkins but not to Rosalind Franklin who died of cancer at 37 from the x-ray data that provided the answers.
What are the DNA side rails composed of?
A sugar phosphate backbone
What are the horizontal rails called?
Base pairs
What are the horizontal rails composed of?
PURINES - a double
carbon-nitrogen ring

Can be guanine


uracil - RNA only
thymine - DNA only
cytosine - both
What is Complementary Base Pairing?
The Nitrogenous bases form hydrogen bonds

The following Base pairs are formed
A-T and C-G

Law of complementary base pairing
one strand determines base sequence of another
Law of complementary base pairing
What are the functions of DNA?
1. Serves as code for protein (polypeptide) synthesis

2.Gene - sequence of DNA nucleotides that codes for one polypeptide
Two items

DNA makes up a Gene. Genes make up a Chromosome.
What is the Human Genome?
Genome - all the genes of one person

humans have estimated 35,000 genes

base sequence of all human genes (6 billion base pairs).
human genome project completed in 2000 mapped it
What is the function of RNA?
The essential function is to interpret the DNA code and direct protein synthesis in the cytoplasm
What is the structure of RNA?
RNA is much smaller than DNA (fewer bases)

transfer RNA (tRNA) has 70 - 90 bases

messenger RNA (mRNA) has over 10,000 bases

Where DNA has over 6 billion base pairs

RNA has only one nucleotide chain (not a helix)

ribose replaces deoxyribose as the sugar
uracil replaces thymine as a nitrogenous base
Give the sequence of protein synthesis.
1. Transcription - messenger RNA (mRNA) is formed next to an activated gene

2. mRNA migrates to cytoplasm

3. transfer RNA delivers the amino acids to the ribosome

4. Translation - mRNA code is “read” by ribosomal RNA as amino acids are assembled into a protein molecule
How is DNA Replication accomplished?
The Law of complimentary base pairing allows building of one DNA strand based on the bases in 2nd strand
What are the steps in DNA Replication?
1. DNA helicase opens short segment of helix
point of separation called replication fork

2. DNA polymerase
strands replicated in opposite directions
What are DNA mutations?

What is the DNA error rate?
Changes in DNA structure due to replication errors or environmental factors

Some cause no effect, some kill cell, turn it cancerous or cause genetic defects in future generations

1 error per 1,000,000,000 bases copied
List the pases of the Cell Cycle.
1. G1 phase, the first gap
normal cellular functions
begins to replicate centrioles

2. S phase, synthesis phase
DNA replication

3. G2 phase, second gap phase
preparation for mitosis
replicates centrioles, synthesizes enzymes for cell division

4. M phase, mitotic phase
nuclear and cytoplasmic division

NB: G0 phase, cells that have left the cycle
What is Mitosis?
The process by which one cell divides into 2 daughter cells with identical copies of DNA
What are the functions of Mitosis?
1. embryonic development

2. tissue growth

3. replacement of old and dead cells

4. repair of injured tissues
nuclear division
What are the phases of mitosis?
1. prophase

2. metaphase

3. anaphase

4. telophase
What happens during Prophase?
Chromatin supercoils into chromosomes
each chromosome = 2 genetically identical sister chromatids joined at the centromere
each chromosome contains a DNA molecule

Nuclear envelope(membrane) disintegrates

Centrioles sprout microtubules pushing them apart towards each pole of the cell
What happens during Metaphase?
Chromosomes line up on equator

Spindle fibers (microtubules) from centrioles attach to centromere

Asters (microtubules) anchor centrioles to plasma membrane
What happens during Anaphase?
Centromeres split in 2 and chromatids separate

Daughter chromosomes move towards opposite poles of cells

Centromeres move down spindle fibers by kinetochore protein (dynein
What happens during Telophase?
Chromosomes uncoil forming chromatin

Nuclear envelopes form

Mitotic spindle breaks down
What is Cytokinesis?
The division of the cell cytoplasm

It overlaps telophase
How is is Cytokinesis accomplished?
Myosin pulls on microfilaments of actin in the membrane skeleton

Causes crease around cell equator called cleavage furrow

Cell pinches in two
What cell phase begins after Cytokinesis?
Interphase has begun
What influences the timing of cell division?
Cells divide when:

they have enough cytoplasm for 2 daughter cells

DNA is replicated

there is an adequate supply of nutrients

there is Growth factor stimulation

there is an open space in tissue due to neighboring cell death
When do cells stop dividing?
When there is:

Loss of growth factors or nutrients

Contact inhibition
What is Heredity?
Heredity = transmission of genetic characteristics from parent to offspring
What is a Karyotype?
Karyotype = chart of chromosomes at metaphase
What are Somatic cells??
Somatic Cells are all cells other than sperm or eggs.
How many pairs of chromosomes do humans have in Somatic cells?
Humans have 23 pairs homologous chromosomes in SOMATIC cells (diploid number)
1 chromosome inherited from each parent
22 pairs called autosomes
one pair of sex chromosomes (X and Y)
normal female has 2 X chromosomes
normal male has one X and one Y chromosome
How many pairs of chromosomes do humans have in Genetic cells?
Sperm and egg cells contain 23 haploid chromosomes

paternal chromosomes combine with maternal chromosomes
What are Gene loci?
The location of a gene on the chromosome
What are Alleles?
different forms of gene at same locus on 2 homologous chromosomes
What is a Dominant allele?
It produces protein responsible for visible trait
What is a Recessive allele?
expressed only when both alleles are recessive

usually produces abnormal protein variant
Define the Gene pool?
The collective genetic makeup of a whole population
What are Multiple alleles?
more than 2 alleles for a trait

such as IA, IB, i alleles for blood type
What are Codominant alleles?
Both alleles are expressed,

IAIB = type AB blood
What is Incomplete dominance?
The phenotype is intermediate between traits for each allele
What is Polygenic Inheritance?
2 or more genes combine their effects to produce a single phenotypic trait

such as skin and eye color, alcoholism and heart disease
What is Pleiotropy?
A single gene causes multiple phenotypic traits (ex. sickle-cell disease)
What is a tumor?
Tumors (neoplasms)

are abnormal growth, when cells multiply faster than they die

oncology is the study of tumors
oncology is the study of tumors
What are the characteristics of benign tumors?
connective tissue capsule, grow slowly, stays local

potentially lethal by compression of vital tissues

usually have a round capsule
What are the characteristics of malignant tumors?
unencapsulated, fast growing, metastatic (causes 90% of cancer deaths)

have finger-like outgrowths
What are the causes of Cancer?
Carcinogens - estimates of 60 - 70% of cancers caused by environmental agents

Chemical - cigarette tar, food preservatives

Radiation - UV radiation, alpha particles, gamma rays, Beta particles

type 2 herpes simplex - uterus, hepatitis C - liver
What are is a Mutagen?
a chemical or physical agent that induces or increases genetic mutations by causing changes in DNA.

It triggers gene mutations

the cell may die, be destroyed by immune system or produce a tumor
What are the body's defenses against mutagens?
1. Scavenger cells - remove them before they cause genetic damage

2. Peroxisomes - neutralize nitrites, free radicals and oxidizing agents

3. Nuclear enzymes - repair DNA

4. Tumor necrosis factor (TNF) from macrophages and certain WBCs destroys tumors
Four ways
What is an Oncogene?
A gene capable under certain conditions of causing the initial and continuing conversion of normal cells into cancer cells.
What are Sis and Ris Oncogenes?
Sis oncogene causes excessive production of growth factors - stimulate neovascularization of tumor

Ras oncogene codes for abnormal growth factor receptors - sends constant divide signal to cell
They usually occur together
What are Tumor suppressor genes?
They inhibit development of cancer

damage to one or both removes
control of cell division
What are the effects of Malignancies?
Displaces normal tissue, organ function deteriorates

Block vital passageways
block air flow and compress or rupture blood vessels

Diverts nutrients from healthy tissues - tumors have high metabolic rates

They cause weakness, fatigue, emaciation, susceptibility to infection
What is Cachexia?
cachexia is extreme wasting away of muscle and adipose tissue
What is the end product of Mitosis?
Mitosis produces 2 genetically identical daughter cells (occurs in tissue repair & embryonic growth)
What is the end product of Meiosis?
Meiosis produces gametes - haploid cells required for sexual reproduction

2 cell divisions (after only one replication of DNA)

meiosis I separates homologous chromosome pairs producing 2 haploid cells

meiosis II separates duplicated sister chromatids producing 4 haploid cells