Form and Functions -- Carbohydrates, Lipids, Proteins, Membrane Transport, Compartmentalization, Specialization

cell differentiation

the process by which a cell develops certain structures so that it can carry out certain functions

undifferentiated cells

cells that cannot carry out any specific function as they lack the structures to do so

embryonic cells

cells that are undifferentiated and therefore cannot carry out specific functions

genes in the cell are turned on or off

how cells become specialized

gene expression

process by which a gene produces its product and the product carries out its function

cellular environment

controls which genes are turned on or off in an undifferentiated cell

multicellularity

trait of eukaryotes that evolved repeatedly over time

fungi, plants, algae, animals

types of organisms that are multicellular

specialized

what being multicellular allows cells to become

larger

body size of multicellular organisms in relation to unicellular organisms

allows organisms to more easily adapt to changes in their environment

advantage of being multicellular and having specialized cells

cell specialization

allows cells to perform functions with increased efficiency

zygote

fertilized egg

fertilization

fusion of an egg and sperm cell to form a zygote

mitosis

a process by which cells replicate so that they each have identical genetic information

differential gene expression

turning different genes on or off

chemical gradients of signaling gradients

why the position of a cell in the embryo determines how it differentiates

morphogens

signaling chemicals

its varying concentrations lead genes to be expressed or not expressed

how morphogens affect cell differentiation

can divide infinitely, capable of differentiating along different pathways

properties of stem cells

totipotent stem cell

stem cell that can differentiate into any type of specialized cell and can give rise to a whole organism

pluripotent stem cell

type of stem cell which has the ability to differentiate into almost any cell type in the body and therefore cannot give rise to a whole organism

multipotent stem cell

a stem cell only able to develop into a few related types of cell

unipotent stem cell

stem cell that can only differentiate into one type of cell

first eight cells of the morula

example of totipotent stem cells

embryonic stem cells

example of pluripotent stem cells

umbilical cord stem cells

example of multipotent stem cells

liver cells

example of unipotent stem cells

bone marrow, skin, liver

examples of where stem cells are present in the adult body

allows tissues to repair

why stem cells are in bone marrow, skin, and liver in adults

stem cell niche

an area of a tissue that provides a specific microenvironment in which stem cells are present in an undifferentiated and self-renewable state while also allowing them to rapidly differentiate when needed

grow stem cells

by recreating a stem cell niche, scientists are able to

sperm cell

pretty long with a length of 50 micrometers which gives it less resistance when swimming and exists to deliver DNA to egg cell

egg cell

largest cell at 110 micrometers which allows for nutrition storage for development of the embryo

white blood cell

10 micrometers when unused but 30 micrometers when used due to more rough endoplasmic reticulum and golgi body

cerebellar granular cell

very small which allows the cerebellum to accommodate around 50 billion of them

sa/v

surface area to volume ration

mm squared

what is surface area measured in

mm cubed

what is volume measured in

volume of the cell

the rate of reactions inside a cell is proportional to the

substances for the reactions must be moved inside the cell, waste products are removed

required for efficient cell reactions

surface area

affects the rate that substances can travel across the cell membrane

the more efficient cells are

the bigger the sa/v ratio

small

for cells to have a large sa/v ratio, they must be

6 to 8 micrometers

size of red blood cells

so they can fit through capillaries

why red blood cells are small

biconcave

shape of red blood cells

maximizes sa/v ratio

why does the red blood cell have a biconcave shape

high rates of diffusion, unloading of oxygen

why the red blood cell has a high sa/v ratio

red blood cell

proximal convoluted tubule

skeletal muscle

proximal convoluted tubule

a tube part of the nephron that has many foldings giving it increased surface area that allow increased diffusion, bettering its ability to regain beneficial molecules filtered out of the blood

nephron

functional unit of the kidney

alveoli

air sacs that the lungs house many of that have a high surface area so as to improve diffusion of gases

1 cell

thickness of the wall of the alveoli

pneumocytes I and pneumocytes II

parts of the alveoli

pneumocytes I

part of alveoli designed for gas exchange that is very thin at about 0.15 nanometers and since the capillary is also very thin there is only about 0.5 nanometers of space between the alveoli and blood

pneumocytes I

red arrow

pneumocytes II

the more numerous type of alveoli that has a lot of cytoplasm, and secretory vesicles which emit a surfactant that decreases surface tension therefore preventing collapsing as well as keeping the alveoli moist which allows gases to dissolve and diffuse more easily

pneumocytes II

myofibril

long protein filaments in muscles responsible for contraction and relaxation of muscles

striated muscles and cardiac muscle cells

types of muscles

striated muscle

muscles made of cylindrical fibers formed from fusing individual cells that have a sarcolemma and therefore are multinucleate that connect to the bones of the skeleton and cause voluntary movement

striated muscle

cardiac muscle cell

myogenic muscle cells high in mitochondria found within heart tissue that cause the heart to beat and are branched so that electrical signals can spread through the heart wall and are connected with gap junctions at intercalated discs

cardiac muscle cell

cardiac muscle cell

sarcolemma

continuous plasma membrane in striated muscle

muscle bundle

bundles of fibers enclosed in connective tissue in striated muscle

allow for greater length of contraction

why striated muscles are long and narrow

intercalated discs

longer period of reset between contraction and refraction, does not become fatigued, interconnected cells can work separately as they are separated by atria and ventricles

unique properties of cardiac muscle cells

gamete

sex cell

head, acrosome cap, centrioles

parts of the head region of the sperm

head

part of sperm that contains the paternal DNA and one copy of every chromosome

acrosome cap

part of sperm that contains hydrolytic enzymes which allow the sperm to break through the egg

centrioles

part of sperm that help the zygote divide

mid-piece

part of sperm containing the mitochondria needed to move the tail of the sperm

flagellum

bends to facilitate movement in the sperm

flagellum

sperm tail

zona pellucida

glycoprotein matrix that is the barrier to sperm entry in the egg

corona radiata

external layer of follicular cells that nourish the egg

it is fertilized by the sperm

the egg cell stays in metaphase II until

gas exchange

exchange that is vital for organisms

their environment

where organisms absorb gas from

their environment

where organisms release gas to

diffusion

how gases are absorbed and released in organisms

diffusion

a slow process where molecule move from high to low concentration

large surface areas or small distances

only areas where gas exchange is rapid enough to take place

large surface area, permeability, made of thin tissue layer, moist surface, maintain their concentration gradient

properties of gas exchange surfaces

more surface available for gases to diffuse across,

why gas exchange surfaces have a large surface area

must have openings that allow gases to be exchanged

how gas exchange surfaces must be permeable

shorter distance to diffuse across

why gas exchange surfaces are made of thin tissue layers

helps dissolve gases before they diffuse

why gas exchange surfaces have a moist surface

for diffusion to occur there must be a difference in concentration between two areas

why gas exchange surfaces must maintain their concentration gradient

dense networks of blood vessels, continuous blood flow, ventilation

how concentration gradients are maintained

air

ventilation in lungs

water

ventilation in gils

blood and water flow in opposite direction allowing oxygen in the water to diffuse into the blood

how concentration gradient is maintained in gills