Bio 111 Exam 2

Eukaryotic cells

• a “true” nucleus enclosed within a plasma membrane.

• Includes plants and animals

• membrane-bound organelles, including the nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosomes.

Plasma membrane

• known as the cell membrane, a flexible barrier that surrounds the cell

• phospholipid bilayer with embedded proteins, cholesterol, and etc

• The plasma membrane regulates the movement of substances in and out of the cell, allowing for selective permeability. I

• cell signaling and communication.

Prokaryotic cells

• lack a nucleus and other membrane-bound organelles

• smaller and simpler in structure

• include bacteria and archaea. They reproduce through binary fission, a process where the cell divides into two identical daughter cells.

Cytoplasm

• gel-like substance found within cells

• composed of water, salts, and various organic molecules.

• responsible for supporting the organelles within the cell and facilitating their movement.

• many cellular processes, such as protein synthesis and metabolism, occur within

Nucleus

• found in the center of eukaryotic cells.

• contains the cell's genetic material, including DNA, and is responsible for controlling the cell's activities.

• surrounded by a nuclear envelope, which separates it from the rest of the cell.

• Within the nucleus is a dense region called the nucleolus, where ribosomes are synthesized.

• cell division, gene expression, and the overall functioning of the cell.

Chromatin

• complex of DNA, RNA, and proteins found in the nucleus of eukaryotic cells.

• makes up chromosomes and plays a crucial role in gene regulation and DNA packaging.

Chromosomes

• thread-like structures made of DNA and proteins found in the nucleus of cells.

• carry genetic information in the form of genes, which determine an organism's traits and characteristics.

• Humans typically have 46 chromosomes (23 pairs), with one set inherited from each parent.

• cell division and reproduction, ensuring the accurate transmission of genetic material to offspring.

Nuclear Pores

Release RNA that is produced inside the nucleus

Ribosomes

• Small structures responsible for protein synthesis.

• can be found in the cytoplasm of both prokaryotic and eukaryotic cells, as well as on the endoplasmic reticulum in eukaryotic cells.

• read the genetic information encoded in messenger RNA (mRNA) and use it to assemble amino acids into polypeptide chains, which then fold into functional proteins

• are essential for cell growth, development, and maintenance.

Glycocalyx

a layer of polysaccharides that lies outside the cell wall in some bacteria

Cyanobacteria

a form of bacteria that are capable of photosynthesis in the same manner as plants.

chromoplasts

• specialized plastids found in plant cells that are responsible for the synthesis and storage of pigments

• They give fruits and flowers their vibrant colors. Unlike chloroplasts, which are involved in photosynthesis, chromoplasts do not contain chlorophyll.

• use solar energy to synthesize carbonhydrates

Thylakoids

• flattened sac within a granum of chloroplast

• location where the light reactions of photosynthesis occur

• stacked to form grana

Stroma

• supportive tissue found in plant leaves, stems, and other organs.

• In chloroplasts, refers to the fluid-filled space surrounding the thylakoid membranes where the light-independent reactions of photosynthesis occur.

  • contains enzymes

Leucoplasts

colorless plastids store oils and starches

Mitochondria

• double-membraned organelles found in eukaryotic cells.

• "powerhouses" of the cell because they generate most of the cell's energy through cellular respiration.

• have their own DNA and can reproduce independently within the cell.

• involved in cellular respiration

  • inner membrane surrounds the matrix, semifluid that contains mitochondrial DNA & ribosomes

Golgi Body

• found in eukaryotic cells.

• involved in the processing, packaging, and distribution of proteins and lipids within the cell.

• It receives proteins and lipids from the endoplasmic reticulum and modifies them by adding sugars and other molecules.

• These modified molecules are then sorted and packaged into vesicles for transport to their final destinations within the cell or for secretion outside the cell.

Vesicles

• produced by Golgi Body

• transport proteins

Cell

smallest unit of living matter

Endosymbiotic theory

• mitochondria and chloroplasts, were once free-living prokaryotic organisms that were engulfed by a large eukaryotic cell.

• a mutually beneficial relationship developed (endosymbiosis), the smaller species lives inside larger species

• energy organelles occurred when larger eukaryotic cells engulfed smaller prokaryotic cells

Cell wall

maintains the shape of cell and strengthened by peptidoglycan

Endomembrane system

• network of membranes within a eukaryotic cell that work together to transport molecules, synthesize proteins, and modify and package molecules for transport within and outside the cell.

• It includes the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and plasma membrane.

Rough ER

has ribosomes

• involves in protein sorting

Smooth ER

lack ribosomes

• detoxification

Plant cells

• cell wall made of cellulose, which provides support and protection.

• contain chloroplasts, responsible for photosynthesis, which animal cells lack.

• have a large central vacuole that stores water, nutrients, and waste products.

• have various organelles like the nucleus, mitochondria, endoplasmic reticulum, and Golgi apparatus, similar to animal cells

• plant growth, development, and reproduction.

Peroxisomes

• the breakdown of fatty acids and the detoxification of harmful substances.

• contain enzymes such as catalase and peroxidase, which help carry out these functions.

• catalyze reactions that produce hydrogen peroxide (H2O)

Lysosomes

• contain digestive enzymes that break down waste materials, cellular debris, and foreign substances.

• cellular waste management and recycling processes.

Vaculoes

stores water, nutrients, waste products

• plants have a central vaculoe, 90% takes up cell

Chloroplast

• in plant cells and some algae.

• It is responsible for photosynthesis, the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen.

• contain chlorophyll, a pigment that captures light energy, and other enzymes necessary for photosynthesis.

• They have a double membrane and contain their own DNA.

Cytoskeleton

• maintains cell shape

• movement

• make internal transports possible

Actin filaments

• microfilaments, are thin protein fibers found in the cytoplasm of eukaryotic cells. They are composed of actin monomers that polymerize to form long, flexible filaments (pearl necklace).

• cell movement, muscle contraction, cell division, and maintenance of cell shape.

Intermediate filaments

• cytoskeletal protein found in the cells of many organisms.

• They provide structural support and help maintain the shape and integrity of cells.

  • composed of various proteins, such as keratins, vimentin, and neurofilaments, which form a network of filaments throughout the cell.

Microtubles

• cylindrical structures found in cells that play a crucial role in various cellular processes.

• composed of tubulin protein subunits and are involved in cell division, cell shape maintenance, intracellular transport, and the movement of organelles.

• form the structural framework of cilia and flagella, which are involved in cell motility.

• serve as tracks for motor proteins to transport vesicles and other cellular components within the cell.

Spirillum

a type of bacteria that has a spiral or helical shape.

Coccus

type of bacteria that has a spherical or circle shape

Bacillus

type of bacteria that has a rod like shape

Membrane Permeability

• the ability of substances to pass through a cell membrane.

• can vary for different substances, with some being able to freely pass through, while others require specific transport mechanisms.

Channel Protein

allows a particular molecule or ion to cross the plasma freely

• allows a substance to simply move from one side to the other

Carrier Protein

selectively interacts with a specific molecule so that it can cross the plasma membrane.

• receive a substance and change its shape

• transports sodium and potassium ions

Cell Recognition Protein

the MHC (major histocompatibility complex) glycoproteins are different for each person, so organ transplants are difficult to achieve.

• help the body recognize when it is being invaded by pathogens

Receptor protein

is shaped in such a way that a specific molecule can bind to it.

• signaling

Enzymatic Protein

enzymes that carry out metabolic reactions

Junction proteins

Tight junctions join cells so that a tissue can fulfill a function

Diffusion

passive transport movement of molecules from a higher to a lower concentration until equilibrium is achieved & molecules are distributed equally.

• lipid-soluble molecules, gases, temp

Bulk Transport

a way large particles (macromolecules) can exit or enter the cell

• exocytosis, moves particles outside the membrane

• endocytosis, moves particles inside the membrane

Aquaporins

allow water to cross a membrane more quickly

Soultion

contains both a solute and solvent

solute

solid

Solvent

liquid

Facilitated transport

• passive transport mechanism in which molecules or ions are transported across a cell membrane with the help of specific carrier proteins.

• allows for the selective movement of substances based on their size, charge, or solubility.

  • glucose, amino acids, and ions such as potassium and calcium.

Active transport

• move molecules or ions across a cell membrane against their concentration gradient, requiring the expenditure of energy.

• This energy is typically derived from ATP (adenosine triphosphate).

• allows cells to transport molecules or ions from an area of lower concentration to an area of higher concentration.

• sugars, amino acids, ions

osmosis

movement of water across a selectively permeable membrane from high to low concentration

• does not require energy

Osmotic pressure

the greater the possible pressure, the more likely it is that water will diffuse in that direction

Isotonic

has the same concentration of solutes as the cell or system it is being compared to.

• there is no net movement of water across the cell membrane, resulting in a stable cell volume.

Tonicity

Tonicity refers to the relative concentration of solutes in a solution compared to the concentration of solutes inside a cell. It determines the direction and extent of water movement across a cell membrane. A solution can be hypertonic (higher solute concentration), hypotonic (lower solute concentration), or isotonic (equal solute concentration) to a cell.

Hypertonic soultion

higher-solute concentration (less water) than the cytoplasm of a cell

• cell loses water

  • crenation: in animal cells, shriveling of the cell

  • plasmolysis: in plant cells, shrinking of the cytoplasm

Hypotonic solution

solution that contains a lower-solute (more water) concentration than the cytoplasm of a cell

• cell gains water

  • Hemolysis: bursting of a red blood cell

As a cell increases in size..

surface-area-to-volume ratio decreases

surface area and volum increases

Cilia

short hairlike projection

Myosin

responsible for attaching and pulling the other filaments along

Fluidity of a membrane increases the percentage of unsaturated fatty acids in the phospholipids decreases.

False

Phagocytosis

• type of endocytosis where a cell engulfs solid particles, such as bacteria or cellular debris, by forming a phagosome.

Pinocytosis

form of endocytosis where cells take in fluid and dissolved solutes by forming small vesicles.

Receptor-mediated endocytosis

• a process by which cells take in specific molecules from the extracellular environment.

Extracellular matrix

helps some celss adhere to neighboring cells

Gap Junctions

allow direct communication between adjacent cells.

Desmosomes

provide strong adhesion between cells.

• commonly found in tissues that experience mechanical stress, such as the skin and heart muscle.

Cell cycle

Interphase & Mitotic stage

• cell grows larger

• number of organelles doubles

• DNA is replicated

Interphase

DNA replication

G1 phase

cell growth occurs

S phase

chromosomes replicate

• sister chromatids are made

  • centromere: waist of the duplicated chrromosomes

G2 phase

synthesize proteins during mitosis and cytokinesis

Mitotic

Mitosis: nuclear division

Cytokinesis: cell complete phase; division of the cytoplasm

• results in 2 genetically identical daugther cells

Cyclins

family of proteins increase and decrease as cell cycle. continues

• without it cell cycle stops at G1, M, or G2

• must be present for cell to proceed from one stage to the next

Prophase

nucleoli disappear

centrosomes move apart

splindle fibers start to form

Metaphase

chromosomes line down the metaphase plate in a single row

• consist of 2 chromatids

Anaphase

Sister chromatids separate

• now called chromosomes

spindle fibers shorten

Telophase

2 daughter nuclei reorganize

splindle fibers disapper

nuclear evelopes and nucleoi reform

2 genetically identical daughter nuclei

Haploid

half the usual number of chromosomes. In humans, haploid cells are the sperm and egg cells, which contain 23 chromosomes each.

Diploid

contains two sets of chromosomes, one set inherited from each parent. In humans, diploid cells have 46 chromosomes, with 23 chromosomes coming from the mother and 23 from the father.

Cloning

Clon

creating an identical copy of an organism or a specific gene or DNA sequence. It can be done through various techniques, such as somatic cell nuclear transfer or gene cloning.

interkinesis

a period of rest that cells of some species enter during meiosis between meiosis I and meiosis II.

oncogene

has the potential to cause cancer. When these genes are mutated or activated, they can promote abnormal cell growth and division, leading to the development of tumors.

• can be derived from normal genes called proto-oncogenes, which are involved in regulating cell growth and division. Mutations or alterations in proto-oncogenes can convert them into oncogenes, disrupting the normal control mechanisms of cell growth and contributing to the development of cancer.

Angiogenesis

the growth of new blood vessels into cancerous tissues

Tumor suppressor genes

a class of genes that help regulate cell growth and prevent the formation of tumors.

• They play a crucial role in maintaining the normal functioning of cells and preventing the development of cancer.

• Mutations or inactivation of tumor suppressor genes can lead to uncontrolled cell growth and an increased risk of cancer.

Eukaryotic chromosomes

structures found in the nucleus of eukaryotic cells that contain DNA.

• They are composed of chromatin, which consists of DNA tightly wrapped around proteins called histone

• They play a crucial role in storing and transmitting genetic information during cell division.

Binary Fission

a form of asexual reproduction in which a single organism divides into two identical daughter cells.

• observed in prokaryotes, such as bacteria.

Homolgous Chromosomes

pairs of chromosomes that have the same genes at the same loci, but may have different alleles.

come together & line side by side forming a synaptonemal complex

• They are similar in size, shape, and carry genetic information for the same traits.

• During meiosis, homologous chromosomes undergo crossing over, which leads to genetic variation.

Synapsis

pairing of homolgous chromo.

Tetrad

composed of two homologous chromosomes, each containing two sister chromatids. Therefore, it is composed of four chromatids that line up during meiosis.

Meiosis

purpose to produce haploid cells (gametes) with half the number of chromosomes as the parent cell.

nuclear division that reduces chromosome number of cell by 50%

Genetic variation

enables a species to evolve

• provides more genetic diversity

• increases the chances of survival in changing environments

Chiasma

describe the point of crossing over between homologous chromosomes during meiosis. It is the site where genetic material is exchanged between the chromosomes, resulting in genetic recombination.

Gametogensis

the process of formation and development of gametes (reproductive cells) in organisms.

• In males, it is called spermatogenesis, which occurs in the testes and produces sperm cells.

• In females, it is called oogenesis, which occurs in the ovaries and produces egg cells.

• Both processes involve meiosis, where the number of chromosomes is halved, resulting in haploid gametes.

polar bodies

are small, non-functional cells that are produced during oogenesis (the formation of eggs) in females.

• They are created as a result of the unequal division of cytoplasm during meiosis.

• While the primary oocyte undergoes meiosis, it produces one large egg cell and three smaller polar bodies.

• These polar bodies do not have the ability to be fertilized and eventually disintegrate.

• Their main purpose is to ensure that the majority of the cytoplasm and nutrients are preserved for the developing egg cell.

Chromosome structure

• It consists of DNA molecules tightly coiled around proteins called histones.

• The DNA and histones together form a structure called chromatin.

• During cell division, the chromatin further condenses and becomes visible as distinct structures known as chromosomes.

• Chromosomes have a characteristic X-shaped appearance, with two identical sister chromatids held together by a centromere.