Transcript Life Science

Life Science
SOL Review
Cell Theory
• 3 Key Points
• All living things are
composed of one or more
cells
• All cells come from other
cells
• All functions may be carried
out by cells
Robert Hooke & Cells
• Looked at cork under a
microscope
• Cork comes from a plant
• Plant cells look like boxes due
to their rigid cell wall
• These little “boxes” were the
cork cells
Levels of Cellular Organization
• Going from most simple to most
complex:
Cells  Tissues  Organs  Systems
• The cells are the most basic
• The systems make up all the others
Identifying Organelles & their Function
• Chloroplast
• ONLY found in plant cells, NOT
in animal cells
• Organelle used by plants to
generate their own energy or
make their own food…used in
photosynthesis
• Chloroplasts are why the plant
looks green
Identifying Organelles & their Function
• Vacuole
• Responsible for STORING food,
water, and waste
Identifying Organelles & their Function
• Nucleus
• Contains DNA
• Directs the activities of the cell
Identifying Organelles & their Function
• Mitochondria
• Responsible for the release of
ENERGY to support cell
activities
Identifying Organelles & their Function
• Ribosomes
• Site of protein synthesis (where
the proteins are made)
• Looks like little black dots
• Can be floating around in
cytoplasm or attached to the
endoplasmic reticulum (ER)
Identifying Organelles & their Function
• Endoplasmic Reticulum
• Like a highway system for the
cell
• Network of membranes
• Important in protein transport
within the cell
Identifying Organelles & their Function
• Golgi Body or Golgi Apparatus
• Function = package and process the products of the
endoplasmic reticulum (proteins, lipids, etc.)
Organ Systems & Functions
• Respiratory System
•
•
•
•
Breathing
Primary organ = lungs
Need lungs to take in oxygen
Respiratory system works with
circulatory (blood) system to
pump oxygen to all the body’s
cells
Organ Systems & Functions
• Circulatory System
• Red blood cells carry
oxygen from the lungs to
the body cells
• Our body’s cells must have
oxygen to perform their
basic functions
Organ Systems &
Functions
• Excretory System
• Purpose = to get rid of waste
• Examples:
• Sweat, #1, & #2 
• Another function of sweat is
for temperature control
(evaporative cooling)
• Kidneys help filter liquid
waste
Organ Systems & Functions
• Digestive System
• Purpose = to get energy from
the food we eat
• Primary Organs
• Stomach
• Esophagus
• Small & Large Intestine
Organ Systems & Functions
• Reproductive System
• Purpose = to make babies
• Primary Organs
• Sperm & Egg & the organs
that produce them
Organ Systems & Functions
• Immune System
• Purpose = help keep us
healthy
• Primary Cells:
• White blood cells
Photosynthesis
• Process by which plants
produce their own food
• Plants take in carbon
dioxide & water and
with the help of light
energy produce
glucose (plant food)
and oxygen
Photosynthesis
Reactants (Raw Materials)
carbon dioxide + water
Products
light energy
This whole process is not
only vital for the plants to
create their own energy, but
vital for humans and all
other animals because we
NEED OXYGEN…and we
don’t want carbon dioxide!
glucose + oxygen
Photosynthesis
• Because plants
produce their own
food, they are called
“Producers”
• Producers are at the
base or the
foundation of the
food web and are a
vital part of the food
web
Respiration
• Respiration is kinda like the
“opposite” of photosynthesis
• Photosynthesis produces oxygen
and respiration uses oxygen
• ALL CELLS RESPIRE…plant, animal,
etc. Therefore, both plants and
animals need oxygen
Classification of Life & Characteristics
• One HUGE tool that we use to
classify organisms is to determine if
they have a backbone
• Another is to determine whether
they make their own food – animals
do NOT make their own food, they
must get energy from eating
something, whereas plants do make
their own food (photosynthesis)
Using Pictures to Determine Function
• In trying to determine if a
particular animal swims, look
for webbed feet
• In trying to determine if a
seed is carried by wind, look
for wings
• Be prepared to classify
animals based on information
in a chart
Endoskeleton vs. Exoskeleton
• Endoskeleton = bones are inside
• Examples: humans, dogs, cats, deer,
etc.
• Exoskeleton = skeleton is on the
outside – it’s crunchy
• Examples: insects, lobsters, crabs, etc.
Animal & Plant Symmetry
• Radial Symmetry = body is equally
arranged around a central point
(like a starburst, or the sun
• Bilateral Symmetry = you can draw a
line down the middle and the two
halves look similar (like a person or
a dog)
• Asymmetrical = no symmetry at all
(like an amoeba)
Radial vs. Bilateral Symmetry
Inheritance
• Some things you get from your parents,
passed on through your DNA (genes),
these things are inherited
• eye color, blood type, height (to some
extent)
• Other things depend solely on your
environment (like how much food you
get or how much you train your body)
• reading skill, endurance, broken
bones, language, etc.
DNA
• DNA has several words that are essentially
mean the same thing as it
• Genes
• Chromosomes
• Hereditary Information
• Chromatids
• Genetic Material
• The key to all of these is that they are
contained in the nucleus and they direct
the cells activities and they are passed on
from generation to generation from the
parents to the children
Homozygous vs. Heterozygous
• “Homo” means “same”
• AA or aa
• TT or tt
• “Hetero” means “different”
• Aa
• Tt
Phenotype vs. Genotype
• Phenotype
• What you actually see
• Ex: purple pea plants
• Genotype
• What the genes code for
• Ex: AA or Aa or aa
Dominant vs. Recessive
• Dominant = denoted by a capital letter
o Genotype = AA or Aa
• Recessive = denoted by a small letter
o Genotype = aa
• Phenotype Example:
• AA = purple plants
• Aa = purple plants
• aa = white plants
• THERFORE…purple is dominant over white
Dominant vs. Recessive
Dominant
Purple Pea Plant
AA or Aa
Recessive
White Pea Plant
aa
Asexual Reproduction
• Involves only one parent
• Offspring’s DNA is identical
to the DNA of the parent
• Does not contribute to
genetic diversity
Asexual vs. Sexual Reproduction
Sexual Reproduction
• Involves only two parents
• Offspring gets half the DNA from
one parent (Dad = sperm), half the
DNA from the other parent (Mom =
egg)
• Good for genetic diversity
Meiosis
• Cellular reproduction process
used to produce sperm and
egg
• Sperm and egg have only half
the DNA that our body
(somatic) cells have WHY?
• Because sperm & egg combine
to create the zygote (½ + ½ = 1)
Mitosis
• Cellular reproduction process
used to body cells (like skin, liver,
etc.)
• During mitosis, the doubling of
chromosomes ensures that both
the new cells have identical
genetic makeup
Mitosis vs. Meiosis
Hybrid Vigor
• Genetic Diversity = a good thing
• Hybrid = a cross between to
different species
• Example: buffalo & cattle
• This cross between the two
different species often leads to
offspring that is better adapted to
the environment than either of their
parent species