BIO101 Flashcards
What is the definition of a cell?
A cell is the simplest unit of a living organism and the basic unit of structure and function of all life.
What is cell biology?
The study of structure, function, molecular organization, growth, reproduction, and genetics of cells.
What are the three avenues through which cell biology has been studied?
- Classical cytology
- Cell physiology
- Molecular interpretation of cells
Who proposed the cell theory?
Mathias Jacob Schleiden and Theodor Schwann in 1838.
List the four main points of the cell theory.
- All living things are composed of one or more cells
- All metabolic reactions take place in cells
- All cells come from the division of pre-existing cells
- The cell is the basic unit of structure and function of all life
What are the three basic characteristics shared by all true cells?
- A set of genes for regulating activities
- A limiting plasma membrane for controlled exchange
- Metabolic machinery for sustaining life activities
What is the primary function of the nucleus in an animal cell?
To direct activities of the cell and carry genetic information.
What do mitochondria do?
Generate energy for the cell.
What structure do plant cells have that animal cells do not?
A rigid cell wall.
What are the main differences between prokaryotic and eukaryotic cells?
- Size: Prokaryotic (1-10µm), Eukaryotic (10-100µm)
- Multicellularity: Rare in prokaryotic, common in eukaryotic
- Nucleus: Absent in prokaryotic, present in eukaryotic
- Cell wall: Present in most prokaryotic, only in plant and fungal eukaryotic
- Organelles: Mostly absent in prokaryotic, present in eukaryotic
Fill in the blank: The plasma membrane is described as a _______.
[fluid-mosaic assembly]
What is the function of lysosomes?
Intracellular digestion and breaking down large molecules.
What is the primary site of cellular respiration?
Mitochondria.
What is the role of the Golgi apparatus?
Modifies, packages, and distributes proteins.
True or False: Chloroplasts are present in all living plant cells.
True.
What is the structure of the endoplasmic reticulum?
Sheets of unit membrane forming a tubular network.
What is the significance of ribosomes?
They manufacture proteins.
List two functions of the nucleus.
- Confines and replicates DNA
- Controls metabolic and hereditary activities
Fill in the blank: The _______ is the ‘traffic police’ of the cell.
[Golgi apparatus]
What distinguishes plastids from other organelles?
They are involved in photosynthesis and have double membranes.
What types of molecules can pass through a semi-permeable plasma membrane?
Only water, but no solutes.
What is the primary role of chloroplasts?
Site of photosynthesis.
True or False: All cells have a plasma membrane.
True.
What are the two types of cellular respiration?
- Aerobic
- Anaerobic
What is the primary function of chloroplasts?
Site of photosynthesis (light & dark reactions)
What are the main components of the nucleus?
Nuclear material envelope, nucleolus, chromatin, nucleoplasm
What is the role of the nucleus in the cell?
Confines, replicates & transcribes almost all the cell’s DNA
What is the significance of chromosomes?
Capable of self-reproduction; vital in heredity, mutation, variation & evolutionary development
Describe the structure of ribosomes.
Small, dense, rounded & granular particles of ribonucleoprotein
Where do ribosomes occur in the cell?
Freely in the matrix of mitochondria, chloroplast, cytoplasm or attached to ER and nucleus
What is the primary function of ribosomes?
Provide a scaffold for the ordered interaction of molecules involved in protein synthesis
What are centrioles?
Cylindrical, rod-shaped microtubular structures found in some eukaryotic cells
What is the function of centrioles during cell division?
Forms spindle fibers to separate chromosomes
What are cilia and flagella?
Microscopic, contractile & filamentous processes of the cytoplasm
How do cilia and flagella differ in number and function?
Flagella are fewer (1 or 2), longer; cilia are numerous (3000-14000), shorter
What is the function of vacuoles in cells?
Produces turgor pressure, stores water and chemicals, may store insoluble wastes
What are microbodies?
Membrane-bound spherical bodies associated with ER and mitochondria or chloroplast
What are the primary functions of peroxisomes?
H2O2 metabolism, glycolate cycle, β-oxidation
What distinguishes glycoxysomes from peroxisomes?
Glycoxysomes are found only in plant cells and abundant in germinating seeds
List the characteristics of living things represented by the acronym MR.NIGER D.
- Movement
- Reproduction
- Nutrition
- Irritability
- Growth
- Excretion
- Respiration
- Death
What system did Aristotle use for classification?
Distinguished only between plants and animals based on movement, feeding mechanism, and growth patterns
What is binomial nomenclature?
A system of naming organisms using two Latin names introduced by Carolus Linnaeus
What proposal did Ernst Haeckel make in 1866?
Proposed a third kingdom, Protista, for all single-celled organisms
What did Robert H. Whittaker propose in 1957?
Proposed a fifth kingdom, Fungi, based on unique structure and method of obtaining food
What are the three domains proposed by Carl Woese?
- Archaea
- Bacteria
- Eukarya
Define mutualism.
A type of symbiosis resulting in mutual benefit to interdependent organisms
What is commensalism?
Coaction where one species benefits and the other is neither benefited nor harmed
Give an example of protocooperation.
Water moccasins and large birds like herons and ibises
What is parasitism?
When one species harms another by using it for support, shelter, or food
List the classifications of parasites.
- Viral parasites
- Microbial parasites
- Phytoparasites
- Zooparasites
- Endoparasites
- Ectoparasites
- Permanent and temporary parasites
What are common effects of parasites on hosts?
Damage to body structures, diseases, physiological stress, nutritional deficiency
What role do viruses play in parasitism?
Potent agents of several disastrous diseases of plants and animals
What is the significance of the ciliary or flagella movement?
Provides locomotion to the cell/organism
Fill in the blank: The cilia and flagella are distinguished by their number, size, and _______.
[functions]
What is the definition of parasites in relation to mortality?
Parasites may not cause immediate mortality but cause damage to body structures, which may lead to death if excessive.
What are the causes of diseases due to parasitic association?
Causes include:
* The parasite
* Physiological stress
* Nutritional deficiency
* Poisoning
What are common parasitic agents of disease?
Common agents include:
* Viruses
* Bacteria
* Fungi
* Protozoan parasites
* Worm parasites
* External parasites
What is the role of bacteria in disease?
Bacteria may produce localized inflammatory changes, enter the bloodstream, or produce powerful poisons known as toxins.
What disease is caused by inhalation of Aspergillus spores?
Aspergillosis
What are external parasites often known for?
They often act as vectors, transmitting protozoa, bacteria, and viruses between animals.
What nutritional deficiencies can lead to health issues?
Deficiencies in vitamins or minerals, or improper balance of carbohydrates, proteins, and fats can lead to malformations, lack of vigor, or death.
What is predation?
Predation occurs when members of one species eat those of another species.
List the four types of predation.
Types include:
* Herbivores
* Carnivores
* Insect parasitism
* Cannibalism
What are characteristics of predation?
Characteristics include:
* Well-developed hunting ability
* Predators are specialized or generalized
* Age, size, and strength of prey influence predation
* Predators hunt only when necessary
* Habitat preferences bring predators and prey into contact
* Strong preference for particular prey
What is aposematic coloration?
Aposematic coloration is a form of distastefulness due to toxins, where prey advertise their noxiousness with bright colors.
What is amensalism?
Amensalism refers to the adverse effect of one population on another while the affected population remains stable.
What is allelopathy?
Allelopathy is the suppression of growth in one organism through the chemical release by another organism.
What does Gause’s Principle state?
Complete competitors cannot coexist in the same environment.
What is an ecosystem?
An ecosystem includes all organisms interacting among themselves and with the physical environment, leading to energy flow and material cycles.
What are the two categories of ecosystems?
Categories include:
* Natural ecosystems
* Artificial ecosystems
Define natural ecosystems.
Natural ecosystems operate by themselves without major human interference.
What are the two types of aquatic ecosystems?
Types include:
* Freshwater ecosystems
* Marine ecosystems
What are autotrophic components?
Autotrophic components are producers that convert solar energy into chemical energy.
What is a food chain?
A food chain is the transfer of food energy from producers through a series of organisms.
List the types of food chains.
Types include:
* Grazing food chain
* Detritus food chain
What is the importance of a food chain?
Importance includes understanding relationships, energy flow, toxic substance movement, and biological magnification.
What is a food web?
A food web is a complex network formed by various interconnected food chains.
What are ecological pyramids?
Ecological pyramids are graphic representations of trophic structure and function at successive trophic levels.
What are the three types of ecological pyramids?
Types include:
* Pyramids of Numbers
* Pyramids of Biomass
* Pyramids of Energy
What is energy flow in ecosystems?
Energy flows in one direction from the sun through producers to consumers and decomposers.
What is an ecological niche?
An ecological niche is the specific physical space occupied by an organism and its role in the ecosystem.
What are the three aspects of ecological niche?
Aspects include:
* Spatial or habitat niche
* Trophic niche
* Multifactor or hyper volume niche
What is cell division?
Cell division is the process by which a cell divides to form two new cells, either through mitosis or meiosis.
What is a niche in ecology?
The functional role and trophic position of an organism.
What is a multifactor or hyper volume niche?
The position in the environmental gradient.
What happens when niches completely overlap?
Leads to competition.
What is cell division?
The process by which a cell divides to form two new cells.
What are the two types of cell division?
- Mitosis
- Meiosis
Why is cell division important?
Continuity of life depends on cell division.
What defines the life history of a cell?
The cycle of growth and division.
What is chromatin?
A mass of uncoiled DNA and associated proteins.
What are diploid cells?
Cells with two complete sets of chromosomes (2n).
What are haploid cells?
Cells with one complete set of chromosomes.
What is a gene?
A small segment of DNA that contains information for constructing proteins.
What is a centromere?
The point where two chromatids are attached.
What are the three important aspects of cell division?
- Replication of DNA
- Division of nucleus (karyokinesis)
- Division of cytoplasm (cytokinesis)
What are the three types of cell division?
- Binary fission
- Mitosis
- Meiosis
What is mitosis?
A process that produces two genetically identical cells from one cell.
What is meiosis?
Cell division that results in four daughter cells with half the number of chromosomes.
What occurs during interphase?
DNA and organelles are duplicated.
What are the three parts of interphase?
- G1 (first gap/growth)
- S (DNA synthesis)
- G2 (second gap/growth)
What happens during prophase of mitosis?
- Chromatin condenses into chromosomes
- Nuclear membrane disappears
- Mitotic spindle forms
What is the metaphase plate?
The arrangement of chromosomes at the equatorial plate during metaphase.
What occurs during anaphase?
Centromeres split and chromatids move to opposite poles.
What occurs during telophase?
- Chromosomes cluster at poles
- Nuclear membrane reforms
- Spindle disassembles
What is cytokinesis?
The division of the cytoplasm into two daughter cells.
What is the significance of mitosis?
- Maintains proper cell size
- Maintains DNA and RNA equilibrium
- Supports growth and development
- Replaces dead cells
How does mitosis differ in animal and plant cells?
- Animal cells have centrioles
- Plant cells generally lack centrioles
What is the first meiotic division called?
Heterotypic division.
What key process occurs during prophase I of meiosis?
Crossing over of homologous chromosomes.
What is the result of the second meiotic division?
Four haploid cells.
What is independent assortment?
Random arrangement of chromosomes during metaphase I.
What occurs during Prophase I of meiosis?
Homologous chromosomes become paired and crossing-over occurs between them
This process increases genetic variation among offspring.
What is independent assortment?
The random alignment pattern of homologous pairs in the center of the cell during Metaphase I
This leads to different combinations of chromosomes in gametes.
What happens during Anaphase I?
Homologous chromosomes separate.
What is Interkinesis?
A phase similar to interphase where DNA synthesis does not occur.
What is the significance of crossing over in meiosis?
It provides new combinations of chromosomes and hence new combinations of characters in offspring.
What type of cells undergo meiosis?
Sex cells (gonads).
How many daughter cells are produced in meiosis?
Four daughter cells.
What is the main difference between daughter cells produced by mitosis and meiosis?
Daughter cells from meiosis have half the number of chromosomes and different combinations of genes.
How many phases does meiosis consist of?
Two successive divisions.
What is a dominant allele?
An allele that masks the presence of a recessive allele in the phenotype.
What is codominance?
A situation where two different alleles for a trait are expressed unblended in the phenotype of heterozygous individuals.
What is a carrier in genetics?
An individual who is heterozygous for a trait that only shows up in the phenotype of those who are homozygous recessive.
What does the term ‘genotype’ refer to?
The genetic makeup of an individual.
What is genetic drift?
Evolution resulting from random chance, occurring most rapidly in small populations.
What is the function of DNA?
To store the genetic code for the synthesis of proteins.
Fill in the blank: The first offspring generation is referred to as _______.
F1 generation.
True or False: Mitosis occurs in sex cells.
False.
What are homologous chromosomes?
Chromosomes that are paired during the production of sex cells in meiosis.
What is a genome?
The full genetic complement of an individual or species.
What is genome imprinting?
An inheritance pattern where a gene has a different effect depending on the gender of the parent from whom it is inherited.
What is the difference between heterozygous and homozygous?
Heterozygous has two different alleles (Aa), while homozygous has the same allele at the same locus.
How many chromosomes do humans have in each somatic cell?
46 chromosomes.
What is the role of the gene pool in a population?
It is the collective genotype of a population.
