definitions Flashcards
cell theory
all biological organisms are composed of cells
prokaryotic
organisms who’s cells lack a nucleus and other organelles
eukaryotic
organism whos cells contains a nucleus and other membrane-bound organelles
chloroplast
oval shaped structures in which the process of photosythesis takes place found in plants
cell wall
occurs only in plants and fungi. its a rigid frame like covering that surrounds the cell membrane and gives support and structure to the organism
nucleus
control center of the cell that directs all activities of the cell
vacuole
storage places for surplus food,transported, and processed within the cytoplasm
cell membrane
controls movement of materials in and out of the cell
mitochondria
energy producing organelles in the cell
endoplasmic reticulum
where materials are transported through the cell or to the outside of the cell
cell cycle
cells alternate between stages of dividing and not dividing
What is the Cell Theory?
A fundamental concept in biology that states all living things are composed of cells, cells are the basic unit of life, and all cells arise from pre-existing cells.
The Cell Theory is a cornerstone of modern biology and helps to understand the structure and function of living organisms.
Define Prokaryotic.
Organisms that lack a nucleus and membrane-bound organelles.
Prokaryotes include bacteria and archaea.
Define Eukaryotic.
Organisms whose cells contain a nucleus and membrane-bound organelles.
Eukaryotes include animals, plants, fungi, and protists.
What is the function of Chloroplast?
Site of photosynthesis in plant cells.
Chloroplasts contain chlorophyll, which captures light energy.
What is the purpose of the Cell Wall?
Provides structure and protection for plant cells.
Composed primarily of cellulose.
What is the function of the Nucleus?
Contains the cell’s genetic material and controls cellular activities.
The nucleus is often referred to as the control center of the cell.
What is a Vacuole?
A storage organelle in cells, larger in plant cells.
Vacuoles store nutrients, waste products, and help maintain turgor pressure.
What is the role of the Cell Membrane?
Regulates what enters and leaves the cell.
The cell membrane is selectively permeable.
What is the function of Mitochondria?
Powerhouse of the cell, producing ATP through cellular respiration.
Mitochondria have their own DNA and are involved in energy metabolism.
What is the Endoplasmic Reticulum?
An organelle involved in protein and lipid synthesis.
It exists in two forms: rough (with ribosomes) and smooth (without ribosomes).
What is the function of Centrioles?
Involved in cell division and the organization of the mitotic spindle.
Centrioles are found in animal cells.
What is a Plant Cell?
A eukaryotic cell that has a cell wall, chloroplasts, and large vacuoles.
Plant cells perform photosynthesis and have a fixed shape.
What is an Animal Cell?
A eukaryotic cell that lacks a cell wall and chloroplasts.
Animal cells are flexible and have various shapes.
What is the Cell Cycle?
The series of phases that a cell goes through leading to its division and replication.
Includes interphase, mitosis, and cytokinesis.
What is Mitosis?
The process of cell division that results in two identical daughter cells.
Mitosis is crucial for growth and repair in multicellular organisms.
What are the stages of Interphase?
G1 (cell growth), S (DNA synthesis), G2 (preparation for mitosis).
Interphase is the longest phase of the cell cycle.
What is Cytokinesis?
The division of the cytoplasm into two separate cells after mitosis.
In animal cells, this occurs through cleavage furrow formation.
What are Chromosomes?
Structures made of DNA and proteins that contain genetic information.
Chromosomes are visible during cell division.
List the phases of Mitosis.
- Prophase
- Metaphase
- Anaphase
- Telophase
These phases describe the process of nuclear division.
What occurs during Prophase?
Chromatin condenses into chromosomes, and the nuclear envelope breaks down.
Spindle fibers begin to form during this phase.
What happens during Metaphase?
Chromosomes align at the cell’s equatorial plate.
This is the shortest phase of mitosis.
Describe Anaphase.
Sister chromatids are pulled apart to opposite poles of the cell.
Anaphase ensures each daughter cell receives an identical set of chromosomes.
What occurs during Telophase?
Nuclear membranes reform around each set of chromosomes, which de-condense.
This phase precedes cytokinesis.
What is Meiosis?
A type of cell division that reduces the chromosome number by half, producing gametes.
Meiosis includes two rounds of division: meiosis I and meiosis II.
What is Sexual Reproduction?
A process that involves the combination of genetic material from two parents.
This leads to genetic diversity in offspring.
Define Asexual Reproduction.
A form of reproduction that does not involve the fusion of gametes.
Common methods include binary fission, budding, and fragmentation.
What is Fertilization?
The fusion of male and female gametes to form a zygote.
This process initiates the development of a new organism.
What is a Gamete?
A reproductive cell (sperm or egg) that carries half the genetic information.
Gametes are haploid cells.
Define Zygote.
A fertilized egg that results from the fusion of gametes.
The zygote undergoes division and develops into an embryo.
What is an Embryo?
An early stage of development following the zygote stage.
The embryo develops into a fetus in animals.
What is a Fetus?
The developing organism from the end of the embryonic stage until birth.
In humans, this stage occurs from the ninth week of pregnancy.
What is DNA?
Deoxyribonucleic acid, the molecule that carries genetic information.
DNA is structured as a double helix.
Define Unicellular.
Organisms composed of a single cell.
Examples include bacteria and protozoa.
Define Multicellular.
Organisms composed of multiple cells.
Examples include plants and animals.
What is a Haploid cell?
A cell that contains one set of chromosomes (n).
Gametes are haploid cells.
What is a Diploid cell?
A cell that contains two sets of chromosomes (2n).
Most somatic cells in animals are diploid.
Define Pollination.
The transfer of pollen from male to female reproductive structures in plants.
Pollination can be cross or self-pollination.
What is an Egg in biological terms?
The female gamete involved in reproduction.
Eggs are usually larger than sperm and contain nutrients for the developing embryo.
What is Sperm?
The male gamete involved in reproduction.
Sperm are typically smaller and motile compared to eggs.
What is Fragmentation?
A form of asexual reproduction where an organism breaks into fragments, each capable of growing into a new individual.
Common in certain species of starfish and worms.
Define Spore Production.
A form of asexual reproduction involving the production of spores that can develop into new individuals.
Fungi and some plants reproduce through spores.
What is Budding?
A form of asexual reproduction where a new organism develops from an outgrowth of the parent.
Common in yeast and hydra.
What is Vegetative Reproduction?
A form of asexual reproduction in plants where new individuals arise from vegetative parts.
Examples include runners, tubers, and bulbs.
What is Binary Fission?
A form of asexual reproduction where a single organism divides into two identical daughter cells.
Common in prokaryotic organisms like bacteria.
Define Parthenogenesis.
A form of asexual reproduction where an egg develops into an individual without fertilization.
Observed in some insects, reptiles, and plants.
What is Grafting?
A horticultural technique where tissues from one plant are inserted into another.
Grafting is used to propagate desired plant traits.
What is Cancer?
A disease characterized by uncontrolled cell division.
Cancer cells can invade and damage surrounding tissues.
What is a Carcinogen?
A substance that can cause cancer in living tissue.
Examples include tobacco smoke and certain chemicals.
What is a Tumour?
An abnormal mass of tissue that results from excessive cell division.
Tumours can be benign (non-cancerous) or malignant (cancerous).
Define Clone.
An organism that is genetically identical to another organism.
Cloning can occur naturally or be induced artificially.
What does Homozygous mean?
Having two identical alleles for a particular gene.
Example: AA or aa.
What does Heterozygous mean?
Having two different alleles for a particular gene.
Example: Aa.
Define Hybrid.
The offspring resulting from the cross of two different species or varieties.
Hybrids often exhibit traits from both parents.
What is a Purebred?
An organism whose ancestors are genetically uniform for a particular trait.
Purebreds are often used in selective breeding.
What are Punnett Squares used for?
To predict the genotypes and phenotypes of offspring from genetic crosses.
Punnett Squares illustrate Mendelian inheritance.
What is a Dominant Trait?
A trait that is expressed phenotypically in the presence of at least one dominant allele.
Dominant traits mask the effects of recessive traits.
What is a Recessive Trait?
A trait that is only expressed phenotypically when two recessive alleles are present.
Recessive traits are masked by dominant traits.
What are Sex Organs?
Organs involved in reproduction, such as testes and ovaries.
They produce gametes and hormones.
What is a Hermaphrodite?
An organism that has both male and female reproductive organs.
Examples include earthworms and some plants.
What is Contraception?
The prevention of pregnancy during or following sexual intercourse.
Methods include hormonal, barrier, and surgical techniques.
What is Artificial Insemination?
A reproductive technology involving the introduction of sperm into a female’s reproductive tract.
Used in both human and animal breeding.
What is In Vitro Fertilization (IVF)?
A medical procedure where an egg is fertilized by sperm outside the body.
IVF is commonly used to assist individuals with fertility issues.
What are Heritable Traits?
Traits that can be passed from parents to offspring through genes.
Examples include eye color and height.
What are Non-Heritable traits?
Traits that cannot be passed to offspring through genes.
Examples include acquired characteristics like muscle mass from exercise.
What is Heredity?
The passing of genetic traits from parents to offspring.
Heredity is the foundation of genetics.
What is a Trait (Alleles)?
A characteristic that is determined by genes, with alleles being different forms of a gene.
Traits can be influenced by environmental factors as well.
What is a Gene?
A segment of DNA that codes for a specific protein or trait.
Genes are the basic unit of heredity.
What is a Genotype?
The genetic makeup of an organism, represented by alleles.
Genotypes can be homozygous or heterozygous.
What is a Phenotype?
The observable physical or biochemical characteristics of an organism.
Phenotype is influenced by genotype and environmental factors.
parts of cell theory
•made of one or more cells
•basic unit of structure and function in all organisms
•come from previously existing cells
difference between mitosis and meiosis
mitosis- identical daughter cells
meiosis- genetically unique
what phase of the cell cycle lasts the longest and identify what the cell is doing in that phase
interphase- cell growth and preparation for division by duplicating genetic material
how does sexual reproduction contribute to genetic variation
offspring inherit one set of chromosomes from each parent
advantages and disadvantages of sexual and asexual reproduction
ad- genetic variation,less disease
dis-energetically expensive
ad-population can increase, only needs one parent
dis-no variation,more prone to disease
why is the microscope important for the advancement of biology
allows scientists to investigate cell structure, observe tiny details and learn abt the presence of microbes
explain cloning and pros and cons
