Lesson 1 Reading Guide What are the phases of the cell cycle? Why is the result of the cell cycle important? The Cell Cycle and Cell Division Cell cycle.
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• What are the phases of the cell cycle?
• Why is the result of the cell cycle important?
The Cell Cycle and Cell Division
• Cell cycle
• Interphase
• Mitosis
• Cytokinesis
• Daughter cell
The Cell Cycle (cont.)
• Most cells in an organism go through a cycle of growth, development, and division called the cell cycle.
• The three major steps in the cell cycle are—interphase, mitosis and cytokinesis.
• Through the cell cycle, organisms grow, develop, replace old or damaged cells, and produce new cells.
• How do unicellular and multicellular organisms differ?
• How does cell differentiation lead to organization within a multicellular organism?
Levels of Organization
• Cell differentiation
• Tissue
• Organ
• Organ system
• All cells in a multicellular organism come from one cell: a fertilized egg.
• The process by which cells become different types of cells is called cell differentiation.
Multicellular Organisms (cont.)
Tissues are groups of similar types of cells in multicellular organisms that work together to carry out specific tasks.
Multicellular Organisms (cont.)
• Humans, like most other animals, have four main types of tissue: muscle, connective, nervous, and epithelial.
Multicellular Organisms (cont.)
• Organs are groups of different tissues working together to perform a particular job.
• Organ systems are groups of different organs that work together to complete a series of tasks.
Multicellular organisms usually have many organ systems that work together to carry out all the jobs needed for the survival of the organism.
• What is sexual reproduction, and why is it beneficial?
• What is asexual reproduction, and why is it beneficial?
• How do the types of asexual reproduction differ?
Sexual and Asexual Reproduction
• Sexual reproduction
• Egg
• Sperm
• Fertilization
• Zygote
• Haploid
• Diploid
• Asexual reproduction
• Fission
• Budding
• Regeneration
• Vegetative Reproduction
• Cloning
• Sexual reproduction is a type of reproduction in which the genetic materials from two different cells combine, producing an offspring.
• The female sex cell, an egg, forms in an ovary.
• The male sex cell, a sperm, forms in the testis.
What is sexual reproduction?
What is sexual reproduction? (cont.)
During a process called fertilization, an egg cell and a sperm cell join together to create a zygote.
• Organisms that reproduce sexually form body cells and sex cells.
• In body cells of most organisms, similar chromosomes occur in pairs.
• Diploid cells are cells that have pairs of chromosomes. Humans have 46 chromosomes in a diploid cell.
• Haploid cells are cells that have only one chromosome from each pair of chromosomes. Humans have 23 chromosomes
Diploid Cells and Haploid Cells
• In asexual reproduction, one parent organism produces offspring without meiosis and fertilization.
• Because the offspring inherit all their DNA from one parent, they are genetically identical to each other and to their parent.
What is asexual reproduction?
Cell division in prokaryotes is known as fission.
Types of Asexual Reproduction
• A prokaryote’s DNA molecule is copied and each copy attaches to the cell membrane.
• The cell grows longer, pulling the two copies of DNA apart while the cell membrane begins to pinch inward along the middle of the cell.
Types of Asexual Reproduction (cont.)
Through fission, the cell splits and forms two new identical offspring.
• In budding, a new organism grows by mitosis and cell division on the body of its parent.
• Budding produces offspring genetically identical to its parent.
Types of Asexual Reproduction (cont.)
Animal regeneration occurs when an offspring grows from a piece of its parent.
Types of Asexual Reproduction (cont.)
• Vegetative reproduction is a form of asexual reproduction in which offspring grow from a part of a parent plant.
• Vegetative reproduction usually involves structures such as the roots, the stems, and the leaves of plants.
Types of Asexual Reproduction (cont.)
• Cloning is a type of asexual reproduction performed in a laboratory that produces identical individuals from a cell or from a cluster of cells taken from a multicellular organism.
• Scientists have been able to clone many animals with the chromosomes from one parent.
Types of Asexual Reproduction (cont.)
• Who is the father of genetics?
• How can the environment affect genetics?
Genetics
• Heredity
• Genetics
• Dominant trait
• Recessive trait
• Gene
• Allele
• genotype
• Phenotype
• Homozygous
• Heterozygous
• Punnett square
• Variation
• Environment
• Sex-linked disorders
• Heredity is the passing of traits from parents to offspring.
• Gregor Mendel is known as the father of genetics—the study of how traits are passed from parents to offspring.
Early Ideas About Heredity
• A dominant trait is a genetic factor that blocks another genetic factor.
– dominant traits are expressed using capital letters
• A recessive trait is a genetic factor that is blocked by the presence of a dominant factor.
– recessive traits are expressed using lower case letters
Mendel’s Conclusions (cont.)
• A gene is a section on a chromosome that has genetic information for one trait.
• The different forms of a gene are called alleles. Each chromosome has one allele for every gene on it.
• The two chromosomes in an offspring cell may have the same or different alleles.
What Controls Traits (cont.)
• Geneticists call how a trait appears, or is expressed, the trait’s phenotype.
• The two alleles that control the phenotype of a trait are called the trait’s genotype.
What Controls Traits (cont.)
• When the two alleles of a gene are the same, the genotype is homozygous.
• If the two alleles of a gene are different, the genotype is heterozygous.
What Controls Traits (cont.)
A Punnett square is a model used to predict possible genotypes and phenotypes of offspring.
Modeling Inheritance
• A farmer who raises vegetables wants to cross two types of corn plants. One type is a homozygous dominant plant with red kernels (RR) and the other is a homozygous recessive plant with white kernels (rr). For these plants, red color is dominant and white color is recessive.
• Create a Punnett square on your notes below to predict the offspring the farmer should expect.
• Next to the Punnett square answer what color the offspring will be. Will the plant produce all red kernels, all white kernels, or a mixture of both colors?
Punnett Square Practice!
• Because there are two factors (the sperm and the egg cell) that contribute to inheritance, the resulting offspring have genetic variation.
• Variation is a slight difference in an inherited trait among individual members of a species.
• Variation can provide resistance to diseases, and can result in natural selection among competitive species.
Genetic Variation Among Siblings
• What are ecosystems?
• What are biotic and abiotic factors?
• How do individuals and groups of organisms interact?
• What are some examples of symbiotic relationships?
Interactions Among Living Things
• Ecosystems
• Abiotic factor
• Biotic factor
• Population
• Community
• Habitat
• Niche
• Symbiotic Relationship
• Ecology is the study of how organisms interact with each other and with their environments.
• Every organism on Earth lives in an ecosystem. An ecosystem is all the living and nonliving things in a given area.
• Different organisms depend on different parts of an ecosystem to survive.
What are ecosystems?
• Abiotic factors are the nonliving parts of an ecosystem.
• Important abiotic factors include water, light, temperature, atmosphere, and soil.
• The types and amounts of abiotic factors in an ecosystem help to determine which organisms can live there.
Abiotic Factors
• Biotic factors are all of the living or once-living things in an ecosystem.
• A population is made up of all the members of one species that live in an area.
• Organisms in a population interact and compete for food, shelter, and mates.
• A community is all the populations that live together in the same place.
Biotic Factors
• Each population has different ways to stay alive and reproduce.
• All of the populations in a community share a habitat, the physical place where a population or organism lives.
Symbiotic Relationships
• A symbiotic relationship is one in which two different species live together and interact closely over a long period of time.
• These relationships can be beneficial to both organisms, beneficial to one and harmful to the other, or beneficial to one and neutral to the other.
Symbiotic Relationships (cont.)
• Mutualism—two species in a community benefit from the relationship.
Types of Symbiotic Relationships
bees and flowers
•The bee gets food from the flower
•The flower is able to reproduce because of the bee
Zebra and Oxpeckers
•The Zebra gets pest control
•The Oxpecker gets food
• Parasitism—one species (the parasite) benefits while another (the host) is harmed.
Types of Symbiotic Relationships
Dogs and Fleas
•The Flea gets food (benefits)
•The Dog is harmed because the flea feeds on its blood
Mistletoe and Tree
•The Mistletoe gets food from the tree(benefits)
•The tree losses food to the mistletoe (harmed)
• Commensalism—one species benefits and the other is neither helped nor harmed.
Types of Symbiotic Relationships
Cattle egrets and livestock
- The Egrets are able to get insects when the livestock eats and they are stirred up out of the field, but the livestock is unaffected
Cocklebur and People/Animals
- The Cocklebur benefits from sticking to a person or animal, so its seeds can be spread over a long distance
• How does energy move in ecosystems?
• How is the movement of energy in an ecosystem modeled?
• How does matter move in ecosystems?
Energy and Matter
• Producer
• Consumer
• Food chain
• Food web
• Energy pyramid
• Organisms get energy from food that they make using light or chemical energy or by eating other organisms.
• When one organism eats another, the energy in the organism that is eaten is transferred to the organism that eats it.
Energy Flow
• Energy travels through organisms, populations, communities, and ecosystems in a flow.
• When energy moves in a flow it does not return to its source, as it does in cycles.
Energy Flow (cont.)
• Scientists classify organisms by the way they get the energy they need to survive.
• Some organisms, such as plants, are able to capture the Sun’s energy directly and convert it into energy-rich sugars that they use for food.
• Almost all energy on Earth comes from the Sun.
Organisms and Energy
• A few organisms are able to capture energy from chemicals in the environment and make food by a process called chemosynthesis.
• Other organisms cannot capture energy from sunlight or chemicals and must obtain their energy by eating food.
• Organisms that cannot make their own food using the Sun must depend on organisms that can.
Organisms and Energy (cont.)
Producers change the energy available in their environment into food energy that they use to live and reproduce.
Consumers cannot make their own food and get energy from eating other organisms
Organisms and Energy (cont.)
A food chain models how food energy moves from the environment to several organisms.
Modeling Energy Flow
• Each stage of a food chain has less available food energy than the last one, because some food energy is converted to thermal energy and moves to the environment.
• A food web is a model that shows several connected food chains.
Modeling Energy Flow (cont.)
• Food chains and food webs are models used to help understand how energy travels through a community.
• Terrestrial and aquatic organisms can interact within a food chain or food web.
• Food webs show that food energy can move through several different pathways.
Modeling Energy Flow (cont.)
A. asexual C.unisexual
B. sexual D.multisexual
In which type of reproduction does the genetic material come from only one parent?
A. mutualistic
B. symbolic
C. parasitic
D. commensal
When two species interact in a way that is beneficial to one, but harms the other species, this is a _____________ relationship.
A. the sun
B. moonlight
C. eating plants
D. minerals in the ground
Where does the all the energy in an ecosystem initially come from?
A. 46, 23
B. 23, 11.5
C. 80, 40
D. 12, 24
In a human diploid cell there are ____ total chromosomes, and in a human haploid cell there are ____ total chromosomes?
A. water
B. soil
C. populations
D. atmosphere
Which of these is NOT an abiotic part of an ecosystem.
A. mutualistic
B. symbolic
C. parasitic
D. commensal
When two species interact in a way that is beneficial to one, but harms the other species, this is a _____________ relationship.
A. mitosis, fission, and budding
B. prophase, metaphase, and anaphase
C. interphase, mitosis, and cytokinesis
D. interphase, cell growth and DNA replication
Which of the following show the three major steps in the cell cycle?
A. tissue, cell, organ system, organ
B. cell, organ, organ system, tissue
C. cell, tissue, organ, organ system
D. organ, tissue, organ system, cell
From the simplest to the most complex, what is the order of the levels of organization in an organism?.
A. Mitosis
B. Budding
C. Meiosis
D. Fission
Which is not a type of asexual reproduction?
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