BSC2085: Module 3

Describe the structure of a phospholipid.

A phospholipid molecule consists of a polar phosphate "head", which is hydrophilic and a non-polar lipid "tail", which is hydrophobic. Unsaturated fatty acids result in kinks in the hydrophobic tales.

Describe the golgi apparatus

manipulates products from the rought ER, and also produces new organelles called lysosomes. Proteins and other products of the ER are sent to the Golgi apparatus, which organizes, modifies, packages, and tags them. Some of these products are transported to other areas of the cell and some are exported from the cell through exocytosis. Enymatic proteins are packaged as new lysosomes (or packaged and sent for fusion with existing lysosomes).

exocytosis

material destined for export is packaged into a vesicle inside the cell. The membrane of the vesicle fuses with the cell membrane, and the contents are released into the extracellular space.

Describe peroxisomes

membrane-bound organelles that contain an abundance of enzymes for detoxifying harmful substances and lipid metabolism

Describe lysosomes

membrane-bound organelles that contain digestive enzymes from breaking down large cellular structures

The two major phases of the cell cycle include ___________ (cell division), and ________, when the cell grows and performs all of its normal functions.

mitosis; interphase

Describe Flagella

move in a corkscrew patter to allow cells to move; cellular appendage

What are the main components of a cell?

plasma (cell) membrane, cytoplasm, and extracellular fluid (ECF)

Phagocytosis

relatively nonselective, the cell takes in a large particle

isotonic

solution has a solute concentration equal to another solution

hypertonic

solution has a solute concentration higher than another solution

hypotonic

solution has a solute concentration lower than another solution

Describe Rough ER

studded with numerous ribosomes, which are sites of protein synthesis

Osmosis

the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration).

Which of the following is not a difference between and RNA? a) DNA contains thymine whereas RNA contains uracil b) DNA contains deoxyribose and RNA contains ribose c) DNA contains alternating sugar-phosphate molecules whereas RNA does not contain sugars d) RNA is single stranded and DNA is double stranded

C) DNA contains alternating sugar-phosphate molecules whereas RNA does not contain sugars

Anaphase

Centromeres split in two; sister chromatids (now called chromosomes) are pulled toward opposite poles; certain spindle fibers begin to elongate the cell

Metaphase

Chromosomes are lined up at the metaphase plate; each sister chromatid is attached to a spindle fiber originating from opposite poles

Telophase

Chromosomes arrive at opposite poles and begin to decondense; nuclear envelope material surrounds each set of chromosomes; the mitotic spindle breaks down; spindle fibers continue to push poles apart

Describe the cytoskeleton

Consists of microtubules, microfilaments, and intermediate filaments. It plays an important role in maintaining cell shape and structure, promoting cellular movement, and aiding cell division. Microtubules radiate out from the centrioles.

True or false: A gene is the instructions to make two proteins.

False: A gene is the instructions to make one protein. It is made up of nucleotide triplets called codons, each of which code for one amino acid.

True or false: Passive transport requires ATP and Active transport does not.

False: Passive transport DOES NOT require ATP while Active transport DOES require ATP

True or flase: The DNA double helix is composed of one complementary strand.

False: The DNA double helix is composed of two complementary strands. The strands are bonded together via their nitrogenous base pairs using hydrogen bonds

Interphase is subdivided into ________,________, and________ phases.

G1, S and G2 phases

Describe ribosomes

Have two subunits that come together to make a complete ribosome. It reads mRNA and carries out translation to make protein.

Filtration

Process by which water an/or particles are driven through membrane by pressure; fluid exits capillary since capillary hydrostatic pressure (35 mm Hg) is greater than blood colloidal osmotic pressure (25 mm Hg)

What are some of the functions of membrane proteins?

Receptors, second-messenger systems, enzymes, channels (open or gated), carriers (includes pumps), cell-identity markers, and cell-adhesion molecules

Describe smooth ER

Synthesizes phospholipids, steroid hormones, regulates the concentration of cellular Ca++, metabolizes some carbohydrates, and breaks down certain toxins

Describe the cell membrane

The cell membrane of the cell is a phospholipid bilayer containing many different molecular components, including proteins and cholesterol, some with carbohydrate groups attached.

Describe the nucleus

The control center of the cell. The nucleus of living cells contains the genetic material that determines the entire structure and function of the cell. The nuclear membrane has two phospholipid bilayers and contains nuclear pores to allow transport into and out of the cell. Ribosomes are produced in the nucleolus.

Describe the mitochondrion

The energy-conversion factory of the cell. -Composed of two separate lipid bilayer membranes. Along the inner membrane are various molecules that work together to produce ATP, the cell's major energy currency

Describe the phospholipid bilayer

The phospholipid bilayer consists of two adjacent sheets of phospholipids, arranged tail-to-tail. The hydrophobic tails associate with one another, forming the interior of the membrane. The polar heads contact the fluid inside (intracellular fluid) and outside of the cell (extracellular fluid).

Simple Diffusion

The structure of a cell's lipid bilayer allows only small, non-polar substances such as oxygen and carbon dioxide to pass through the cell membrane, down their concentration gradient.

__________ within the cell nucleus produces an mRNA molecule, which is modified and then sent into the cytoplasm for translation.

Transcription

True or false: Almost all molecules in plasma membrane are lipids. This would include your phospholipids and cholesterol.

True

True or false: DNA holds all of the genetic information necessary to build a cell's proteins.

True: DNA holds all of the genetic information necessary to build a cell's proteins. The nucleotide sequence of a gene is ultimately translated into an amino acid sequence of the gene's corresponding protein.

True or false: DNA replication faithfully duplicated the entire genome of the cell.

True: DNA replication faithfully duplicated the entire genome of the cell. During DNA replication, a number of different enzymes work together to pull apart the two strands so each strand can be used as a template to synthesize new complimentary strands. The two daughter DNA molecules each contain one preexisting strand and one newly synthesized strand. Thus, DNA replication is said to be "semiconservative".

True or false: Strands of DNA are wrapped around supporting histones.

True: DNA strands are wrapped around support histones. These proteins are increasingly bundles and condensed into chromatin, which is packed tightly into chromosomes when the cell is ready to divide

True or false: in the first of the two stages of making a protein from DNA, a gene on the DNA molecule is transcribed into a complimentary mRNA molecule.

True: in the first of the two stages of making a protein from DNA, a gene on the DNA molecule is transcribed into a complimentary mRNA molecule.

Endocytosis

a form of active transport in which a cell envelopes extracellular materials using its cell membrane; receptor-mediated (very selective); when external receptors bind a specific ligand, the cell responds by endocytosing the ligand

Describe the endoplasmic reticulum (ER)

a winding network of thin membranous sacs found in close association with the cell nucleus.

Place the following structures in order from least to most complex organizations: chromatin, nucleosome, DNA, chromosome: a) DNA, nucleosome, chromatin, chromosome b) nucleosome, DNA, chromosome, chromatin c) DNA, chromatin, nucleosome, chromosome d) nucleosome, chromatin, DNA, chromosome

a) DNA, nucleosome, chromatin, chromosome

Which of the following organelles produces large quantities of ATP when both glucose and oxygen are available to the cell? a) mitochondria b) peroxisomes c) lysosomes d) ER

a) mitochondria

Transcriptions and translation take place in the ________ and ________, respectively. a) nucleus; cytoplasm b) nucleolus; nucleus c) nucleolus; cytoplasm d) cytoplasm; nucleus

a) nucleus; cytoplasm

Which of the following is a function of the rough ER? a) production of proteins b) detoxification c) synthesis of steroid hormones d) regulation of intracellular calcium concentration

a) production of proteins

cytokenesis

animal cells: a cleavage furrow separates the daughter cells plant cells: a cell plate, the precursor to a new cell wall, separates the daughter cells

Which of the following sequences on a DNA molecule would be complementary to GCTTATAT? a) TAGGCGCG b) ATCCGCGC c) CGAATATA d) TGCCTCTC

b) ATCCGCGC

Which of the following phases is characterized by preparation for DNA synthesis? a) G0 b) G1 c) G2 d) S

b) G1

The nucleus and mitochondria share which of the following features? a) protein-lined membrane pores b) a double cell-membrane c) the synthesis of ribosomes d) the production of cellular energy

b) a double cell-membrane

Which of the following is part of the elongation step of DNA synthesis? a) pulling apart the two DNA strands b) attaching complementary nucleotides to the template strand c) untwisting the DNA helix d) none of the above

b) attaching complementary nucleotides to the template strand

Because they are embedded within the membrane, ion channels are examples of ________. a) receptor proteins b) integral proteins c) peripheral proteins d) glycoproteins

b) integral proteins

Choose the answer that best completes the following analogy: Diffusion is to ________ as endocytosis is to ________. a) filtration; phagocytosis b) osmosis; pinocytosis c) solutes; fluid d) gradient, chemical energy

b) osmosis; pinocytosis

The rough ER has its name due to what associated structures? a) Golgi apparatus b) ribosomes c) lysosomes d) proteins

b) ribosomes

What is a primary function of tumor suppressor genes? a) stop all cells from dividing b) stop certain cells from dividing c) help oncogenes produce oncoproteins d) allow the cell to skip certain phases of the cell cycle

b) stop certain cells from dividing

Which of the following is not made out of RNA? a) the carriers that shuffle amino acids to a growing polypeptide b) the ribosome c) the messenger molecule that provides the code for protein synthesis d) the intron

b) the ribosome

How many "letters" of an RNA molecule, in sequence, does it take to provide the code for a single amino acid? a) 1 b) 2 c) 3 d) 4

c) 3

Ion pumps and phagocytosis are both examples of __________ . a) endocytosis b) passive transport c) active transport d) facilitated

c) active transport

What multipotent stem cells from children sometimes banked by parents? a) fetal stem cells b) embryonic stem cells c) cells from the umbilical cord and from the baby teeth d) hematopoietic stem cells from red and white blood cells

c) cells from the umbilical cord and from the baby teeth

Which type of stem cell gives rise to red and white blood cells? a) endothelial b) epithelial c) hematopoietic d) mesechymal

c) hematopoietic

Which of the following structures could be found within the nucleolus? a) chromatin b) histones c) ribosomes d) nucleosomes

c) ribosomes

Which of the following is a feature common to all three components of the cytoskeleton? a) they all serve to scaffold the organeeles within the cell b) they are all characterized by roughly the same diameter c) they are all polymers of protein subunits d) they all help the cell resist compressions and tensions

c) they are all polymers of protein subunits

Describe Cilia

capable of moving to transport mucous; cellular appendage

pinocytosis

cell takes in small particles in fluid.

Prophase

chromosomes condense and become visible; spindle fibers emerge from the centrosomes; nuclear envelope breaks down; centrosomes move toward opposite poles

Prometaphase

chromosomes continue to condense; kinetochores appear at the centromeres; mitotic spindle microtubules attach to kinetochores

A mutation in the gene for a cyclin protein might result in which of the following? a) a cell with additional genetic material b) cancer c) a cell with less genetic material than normal d) any of the above

d) any of the above

The diffusion of substances within a solution tends to move those substances ________ their __________ gradient. a) up; electrical b) up; electrochemical c) down; pressure d) down; concentration

d) down; concentration

Arrange the following terms in order of increasing specialization: oligopotency, pleuripotency, unipotency, multipotency a. multipotency, pleuripotency, oligopotency, unipotency b. pleuripotency, oligopotency, multipotency unipotency c. oligopotency, pleuripotency, unipotency, multipotency d. pleuripotency, multipotency, oligopotency, unipotency

d) pleuripotency, multipotency, oligopotency, unipotency

Choose the term that best completes the following analogy: Cytoplasm is to cytosol as a swimming pool containing chlorine and flotation toys is to ________ . a) the walls of the pool b) the chlorine c) the flotation toys d) the water

d) the water

Facilitated diffusion

diffusion of substances crossing the cell (plasma) membrane takes place with the help of proteins such as channel proteins and carrier proteins. Channel proteins are less selective than carrier proteins, and usually mildly discriminate between their cargo based on size and charge. Carrier proteins are more selective, often only allowing one particular type of molecule to cross.

sodium-potassium pump

found in many cell (plasma) membranes. Powered by ATP, the pump moves sodium and potassium ions in opposite directions, each against its concentration gradient. In a single cycle of the pump, three sodium ions are extruded from and two potassium ions are imported into the cell.

Describe Microvilli

increase surface area to improve absorption; cellular appendage

During __________, the mRNA transcript is "read" by a functional complex consisting of the ribosome and tRNA molecules. tRNAs bring the appropriate amino acids in sequence to the growing polypeptide chain by matching their anti-codons with codons on the mRNA strand. Matching occurs because because the three nucleotides in the anticodon contained in the tRNA specifically bind to the nucleotides in the codon on the mRNA.

translation