AnP Chapter 3 (LO3) Flashcards
Cells
Simplest units of all living matter
Orchestrate all of the processes that make life possible: respiration, movement, reproduction, digestion and excretion
Body consists of about —–different types of cells
200
Nerve cells
Long extensions allow these cells to quickly transmit electrical impulses from one part of the body to another
Muscle cell
Elongated, thread-like fibers can shorten to allow body parts to move
Red blood cell
Concave shape allows these cells to bend and squeeze through tiny blood vessels
Gland cells
Intercellular sacs store and release substances, such as hormones, enzymes, mucus and sweat
Immune cells
These cells can recognize and destroy foreign invaders (such as viruses, fungi, and bacteria) some engulf or destroy foreign cells directly; others manufacture antibodies
Plasma membrane
Surrounds cell
Regulates the passage of substance into and out of the cell
Consists of phospholipids, cholesterol and protein phospholipids
Phospholipids form the bulk of the cell membrane (heads and tails)
phospholipid Bilayer
in effort to keep heads and tails forcing the right ways, the phospholipids position themselves in a double layer
Helps stiffen and strengthen the plasma membrane proteins
Embedded in various spots in the membran
Glycoproteins
proteins that have carbohydrates attached to their outer surface
act as markers to help the body distinguish its own cells from foreign invaders
protein receptors
receptors for specific chemicals or hormones
protein channels
allowing solutes to pass in and out of the cell
NUCLEUS
Central and most important part of the cell
Cells control centre; contains all genetic info
Most cells only have one but liver and skeletal muscles have multiple nucleus’
Mature red blood cells are the only cells that don’t contain nucleus
Nuclear envelope
a double layered membrane that surrounds the nucleus
Nuclear pores
perforate the nuclear envelope
- regulate the passage of molecules into the nucleus and out
- allows RNA to leave to do work in the cytoplasm
Chromatin
throughout nucleoplasm are thread-like structures composed of DNA and protein
Chromosomes:
chromatic coils tightly into short rod-like structures
Nucleolus
center of the nucleus; manufactures components of ribosomes
Cytoplasm
gel like substance that fills the space between the plasma membrane and the nucleus
-hundreds or thousands of organelles are packed into the cytoplasm
Organelles:
“little organs” perform specific tasks in cellular metabolism
Endoplasmic reticulum
a network of membranous canals
- ribosomes dot surface of some ER giving a “rough” appearance AKA rough ER
- smooth ER contains enzymes that synthesize lipids and carbs
Ribosomes
protein and RNA; synthesize proteins
- some attach to ER others are scattered through cytoplasm
- some of the produced protein is used
GOLGI APPARATUS
Made up of flattened membranous sacs stacked on top of each other
Receives proteins from the ER and prepares and packages them for export
steps of how the Golgi apparatus works
- ER delivers a protein molecule to the Golgi apparatus
- The protein passes through each of the sacs of the Golgi apparatus undergoing modifications along the way
- At the end of the process the Golgi apparatus envelopes the protein and then pinches off the portion of itself containing the proton creating a vesicle
- Some vesicles travel to the surface of the cell, fuse with the plasma membrane and pop open to release the protein inside
- Others become lysosomes and some become secretory vesicles that store substances like breast milk or digestive enzymes for later secretion
CENTRIOLES
2 centrioles lie perpendicular to each other just outside the nucleus
Play a role in cell division
LYSOSOMES
(cellular garbage disposals)
Membranous vesicles that form from pinched off pieces of the Golgi apparatus
Contain various enzymes that help break down excess protein
This allows the cell to reuse amino acids
Can be used to destroy bacteria
MITOCHANDRIA
(powerhouse of the cell)
2 membranes: an outer and inner membrane
Cells that do a lot of work contain more mitochondria
Cristae
inner membrane folds back and forth creating these folds
Between the spaces of inner membrane are enzymes that the organelle use to make ATP
CYTOSKELETON
Supporting framework of the cell
Made of protein and rod like structures
Determines the shape of the cell, gives strength and allows it to move
Organizes contents of the cell
In some cells forms microvilli, cilia and flagella
microovilli
Folds of the cell membrane that greatly increase the surface area of the cell
Typically found in cells charged with absorbing nutrients (intestinal)
Can increase cells absorptive area as much as x40
cilia
- hair like processes along the surface of the cell that move
- Beat in waves away in same direction
- Occur primarily in respiratory tract and fallopian tubes
flagella
Similar to cilia hair like projections
Thicker and longer and fewer
Whip like motion that helps move a cell
Only flagellum in the human body is the tail of sperm
Two categories of transportation mechanisms
active or passive transport
PASSIVE TRANSPORT
Don’t require the cells to expand energy
Include diffusion, osmosis, filtration, and facilitated diffusion
DIFFUSION
Involves the movement of particles from an area of higher concentration to an area of lower concentration
Occurs in air or water
Concentration gradient
a difference in concentration of a substance from one point to another
OSMOSIS
Type of diffusion
Involves the diffusion of water down the concentration gradient through selectively permeable membrane
In the body- happens when a particular substance can’t cross the membrane in which water moves in an effort to equalize the concentration
Hydrostatic pressure
h20 diffuses by osmosis into a solution, the volume of that solution increases. As the volume of H20 on side B increases, it exerts more and more pressure against the membrane
Osmotic pressur
H20 pressure that develops in a solution as a result of osmosis —->the more solute in a solution the greater it’s osmotic pressure
OSMOLARITY AND TONICITY
Important when administering IV fluids
Cells contain a variety of solutes ex: salts, sugars, acids and base
The concentration of these solutes determines whether and how much fluid moves into or out of a cell
Osmosis
will occur if a solute can’t move through the plasma membrane
Tonicity
ability of solution to affect the fluid volume and pressure in a cell through osmosis
Isotonic solution
The concentration of solutes is the same as it is in cell
Ex) when a red blood cell is placed in an isotonic solution h20 moves into and out of cell at an equal rate
Hypertonic solution
Contains higher concentration of solutes compared with the fluid within the cell
Ex) if a red blood cell is immersed in a hypertonic solution (ex salt solution) h20 will diffuse out of the cell causing it to shrivel and perhaps die
Hypotonic solution
Contains lower concentration of solutes compared with fluid within cell
Ex) if a red blood cell is placed in a hypertonic solution (distilled h20) h20 will move by osmosis into cell. Causing cell to swell and burst
FILTRATION
Occurs because differences in pressure ex) capillaries
H20 and dissolved particles are forced across a membrane from an area of higher to lower hydrostatic pressure
Hydrostatic pressure of blood inside capillaries forces h20 and dissolved material into surrounding tissue fluid ** this is how cells receive the nutrients the need
The method kidneys use to remove waste products from the blood
FACILITATED DIFFUSION
Some molecules need other molecules to help (facilitate) movement across a membrane
Similar to regular diffusion, molecules move down the concentration gradient from an area of greater to lesser concentration
ACTIVE TRANSPORT
Solutes move up to the concentration gradient from lesser to greater
Moving against the concentration gradient requires energy in form of ATP
Mechanisms include transport by pumps and transport by vesicles
TRANSPORT BY PUMPS
Actively pumping allows cells to move ions and other particles to specific areas
Sodium- potassium pump
regulates the volume of fluid within cells
provides the electrical potential
helps with heat production
transfers sodium from inside to outside
transfers potassium from extra cellular fluid (outside) to inside
how sodium potassium pump works
- 3 sodium ions from inside the cell funnel into receptor sites on a channel protein ‘
- Fueled by ATP the channel protein releases Na+ into extracellular fluid causing them to move from lower to higher concentration
- Meanwhile 2 potassium ions from outside enter the same channel protein
- The potassium are then released inside the cell. This keeps the concentration of K+ higher and Na+ lower within the cell
TRANSPORT BY VESICLES
Cells have ability to move large particles or numerous molecules at once through the plasma membrane
This requires energy
Cell membrane creates a vesicle to transport the matter
ENDOCYTOSIS
The form of vesicular transport that brings substances into the cell
Endo: take into
Plasma membrane traps a substance that’s too large to diffuse and brings it into the cell
2 FORMS OF ENDOCYTOSIS
Phagocytosis (cell eating): occurs when the cell engulfs a solid particle and brings it into the cell ex) white blood cell “consumes” bacteria
Pinocytosis (cell drinking): occurs when tiny vacuoles bring droplets of extracellular fluid containing dissolved substances into the cell
-the cell then uses the engulfed fluid and nutrients
EXOCYTOSIS
Brings substances into the cell using vesicles to release substances outside of the cell
Glands use this to release hormones
In exocytosis a vesicle in the cell containing the materials to be released travels to the cells surface
The vesicle fuses with the plasma membrane and then releases its contents outside the cell
DNA molecule
type of nucleic acid, most complex of all molecules
Genome
complete set genes or genetic material in a cell
Polymer
large molecule made up of many smaller molecules joined together in a sequence that encodes the cell’s genetic info
Nucleotides
“building blocks” of DNA
-each consist of one sugar, one phosphate group and one four possible types of nitrogenous bases
4 TYPES OF BASES:
Adenine (A): can only pair with :Thymine (T)
Guanine (G): can only pair with :cytosine (C)
DNA info
Main function= provide info for building proteins
Proteins are the body’s main structural molecules and contribute to almost every cellular function
DNA is too large to leave the nucleus and needs help from ribonucleic acid (RNA)
DNA structure= double helix
Phosphate group alternates with the sugar deoxyribose to form 2 sides of ladder
RNA
Long chain of nucleotide units consisting of a sugar, phosphate group and nitrogen base
Exists in 3 forms (crucial to protein synthesis)
- Messenger RNA (mRNA)
- Transfer RNA (tRNA)
- Ribosomal RNA (rRNA)
RNA Differs from DNA in 3 ways
RNA is a single strand
RNA contains the sugar ribose instead of deoxyribose
RNA contains the base uracil (U) instead of thymine (T)
PROTEIN SYNTHESIS
Manufactured proteins occur in 2 main phases: transcription and translation
how transcription works with DNA/RNA
1.When the nucleus receives a chemical message to make a new protein the DNA with relevant gene unwinds
2.RNA nucleotides are assembled by an enzyme
The nucleotides attach DNA and bind together to form mRNA
Strand is exact copy of the opposite side of the DNA molecule
- Length of mRNA consists of a series of 3 bases (triplets)
Condon: triplet à the code for one amino acid
how translation works with DNA/RNA
Once in the cytoplasm mRNA attaches to a ribosome
Ribosome consists of rRNA and enzymes
Then translated into a protein
Ribosome reads the codons on strand of mRNA
tRNA is found in the cytoplasm
Anticodon: consists of 3 bases that perfectly complement a specific site (codon) on the mRNA
Amino acid attached to the tRNA
tRNA finds the anticodon and deposits the amino acid
The ribosome uses enzymes to attach the chain of amino acids together with peptide bonds
When each triplet has been filled with the correct amino acid and the peptide bonds have been formed, the protein is complete
Cell life cycle
ability of cells to grow and reproduce
Cell reproduction
ensure genetic info is passed on from one cell to the next
THE CELL CYCLE
First gap phase (G1)
Synthesis phase (S)
Second gap phase (G2)
Mitotic phase (M)
First gap phase (G1)
Cell performs the task for which it was created ex) carrying 02
Accumulates the materials it will need to replicate its DNA
Synthesis phase (S)
The cell makes or synthesizes an extra set of DNA
Second gap phase (G2)
The cell makes final preparations for cell division including synthesizing necessary enzymes
Mitotic phase (M)
Cell division occurs
interphase
time between mitotic phase
G0 (G- zero) phase
some cells leave the cycle and rest/don’t divide
-can last days, years or decades
age
Factor that limits the # of times a cell can divide
Every time DNA replicates the end of chromosomes (telomeres) shorten
Eventually telomeres get too short and essential parts of DNA can be damaged
MITOSIS
When the cell splits into two identical daughter cells
Only cells that don’t divide through mitosis are sex cells
Meiosis
how sex cells divide
4 PHASES OF MITOSIS
prophase
metaphase
anaphase
telophase
PROPHASE
Chromatin begins to coil and condense to form chromosome
Each duplicated chromosome consists of two strands (chromatids) each strand contains a single molecule of DNA
2 chromatids join in the middle at a spot called centromere
Centrioles move to opposite poles of the cell
The nuclear envelope dissolves and spindle fibers form in cytoplasm
METAPHASE
Some of the spindle fibers attach to one side of the chromosomes at the centromere
The chromosomes line up along the center of the cell
ANAPHASE
ANAPHASE
The centromeres divide, forming two chromosomes instead of a pair of attached chromatids
The spindle fibers pull the newly formed chromosomes to opposite poles of the cell
TELOPHASE
A new nuclear envelope develops around each set of daughter chromosomes
The spindle fibers disappear and the cytoplasm divides to produce two identical daughter cells
