Eucaryotes cell physiology

Question 1

What is the nucleus made up of

Answer 1

Nuclear pore
Chromatin
Nuclear enveloppe
Nucleolus

Question 2

Nuclear Pore

Answer 2

Channels in the nuclear envelope that regulate
the exchange of substances (such as RNA and proteins)
between the nucleus and the cytoplasm

Question 3

Chromatin

Answer 3

DNA-protein complex that packages DNA into
compact, dense shape = DNA wrapped around
histone proteins, is the material of which chromosomes are
composed.

Question 4

Nuclear Envelope

Answer 4

Double membrane structure that encloses
the nucleus, separating its contents from the cytoplasm. It
provides a barrier that controls the flow of information and
materials in and out of the nucleus.

Question 5

Nucleolus

Answer 5

Dense region within nucleus responsible for ribosomal RNA (rRNA) synthesis and ribosome assembly

Question 6

Rough endoplasmic reticulum

Answer 6

Studded with ribosomes, involved in the synthesis of proteins

Question 7

Smooth Endoplasmic Reticulum

Answer 7

Lacks ribosomes. It is involved in lipid synthesis, detoxification of drugs and
poisons, and storage of calcium ions

Question 8

Golgi Apparatus (Golgi Vesicles)

Answer 8

Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles

Question 9

Ribosomes

Answer 9

Sites of protein synthesis. Ribosomes translate messenger RNA (mRNA) into polypeptide chains

Question 10

What are the 3 elements of the cytoskeleton

Answer 10

Microtubules
Microfilaments
Intermediate filaments

Question 11

Microtubules

Answer 11

Hollow rods composed of tubulin proteins that help maintain cell shape, enable cell mobility (cilia and flagella),
and facilitate intracellular transport and chromosome separation during cell division

Question 12

Microfilaments (Actin Filaments)

Answer 12

Thin filaments composed of actin that are involved in muscle contraction, cell movement,
and cell division.

Question 13

Intermediate Filaments

Answer 13

Provide mechanical support for the plasma membrane where it comes into contact with other cells
or with the extracellular matrix

Question 14

Mitochondria

Answer 14

The powerhouse of the cell, generating ATP through oxidative phosphorylation, also regulates cell death and calcium ion storage

Question 15

Lysosome

Answer 15

Contains hydrolytic enzymes necessary for intracellular digestion, and breaks down waste materials and cellular debris

Question 16

Peroxisome

Answer 16

enzymes that oxidize certain molecules normally found in the cell, notably fatty acids and amino acids. It also
detoxifies harmful substances, producing hydrogen peroxide as a byproduct, which is then broken down by catalase

Question 17

Plasma Membrane

Answer 17

Semi-permeable membrane that surrounds the cell, providing protection and structural support, controls mvt of substances in and out of cell through transport mechanisms

Question 18

Centrosome

Answer 18

Organizes microtubules and provides structure for the cell and forms
the spindle fibers that separate chromosomes during cell division

Question 19

Secretory Vesicle

Answer 19

Transports materials that are to be secreted from the cell

Question 20

Cytoplasm

Answer 20

Jelly substance containing everything

Question 21

Flagellum

Answer 21

tail that enables cell mobility

Question 22

Chloroplast

Answer 22

Conducts photosynthesis, converting light energy into chemical energy stored in glucose

Question 23

What are the 5 things that the chloroplast does

Answer 23

1) Photosynthesis : captures light to produce ATP and NADPH and release oxygen
2) Synthesis of organic molecules : produces glucose (using calvin cycle that converts CO2 into glucose with ATP and NADPH)
3) Oxygen production : released as a byproduct
4) Storage of starch : converts and stores glucose as starch (to use later for energy)
5) Pigment containment : contains chlorophyll and other pigments for capturing light giving plants their green color

Question 24

What are the 2 methods of passive transport called in membrane transport

Answer 24

Simple Diffusion and Facilitated Diffusion

Question 25

Simple Diffusion

Answer 25

Movement of small non-polar, hydrophobic molecules through the lipid bilayer -Mvt from area of high concentration to low -No energy required

Question 26

Facilitated Diffusion

Answer 26

Movement of larger or polar molecules, such as glucose and ions, through the membrane via specific transport proteins Channel proteins make hydrophilic pathways Rest same as simple diffusion

Question 27

What are the 2 types of active transport

Answer 27

Primary and Secondary

Question 28

Primary Active transport

Answer 28

Use of ATP to transport molecules against their concentration gradient -transports proteins by using energy from ATP hydrolysis to change shape and move molecules across membrane -moves ions against concentration gradients

Question 29

secondary active transport

Answer 29

uses energy of gradient of another molecule to drive the transport of a second molecule against its gradient -= co-transport -uses the energy produced by primary to transport p.ex glucose into the cell against concentration gradient

Question 30

Hydrophilic substance

Answer 30

water soluble and can't pass through hydrophobic lipid bilayer without assistance (need either facilitated diffusion or active transport)

Question 31

Hydrophobic Substances

Answer 31

Lipid-soluble and can easily pass through the lipid bilayer by simple diffusion

Question 32

What are the 3 types of cell-cell interactions

Answer 32

Tight junction Desmosomes Gap Junction

Question 33

Tight Junctions

Answer 33

forms watertight seals between adjacent cells used in intestines or blood-brain barrier

Question 34

Desmosomes

Answer 34

Act like spot welds anchoring cells together used in tissues that experience mechanical stress (skin, heart, muscles)

Question 35

Gap Junctions

Answer 35

Creates channels that allow for direct passage of ion, nutrients, ... used in cardiac and smooth muscle where we need to facilitate synchronized contraction

Question 36

What are the 3 Cytoskeleton Components

Answer 36

Microtubules Microfilaments Intermediate Filaments

Question 37

Microtubules

Answer 37

Hollow tubes made of tubulin proteins Provides structural support, facilitates cell division and enables intracellular transport

Question 38

Microfilaments

Answer 38

Thin filaments made of actin proteins involved in cell mvt, shape maintenance and muscle contraction, also used in cytokinesis during cell division

Question 39

Intermediate filaments

Answer 39

fibrous proteins coiled into cables provide mechanical strength and help maintain cell integrity, by anchoring organelles and supporting cell structure

Question 40

Steps of Bacterial Cell Division (Binary Fission)

Answer 40

1. Initiation of Replication: ○ Chromosome Replication: at the origin of replication (oriC). ○ Bidirectional Replication: DNA replication proceeds bidirectionally from the origin, creating two replication forks that move in opposite directions around the chromosome. 2. Cell Growth: ○ Elongation: As the DNA replicates, the cell elongates. ○ Segregation of Chromosomes: The two copies of the chromosome are separated and moved towards opposite poles of the cell. 3. Formation of the Division Septum: ○ FtsZ Ring Formation: A protein called FtsZ forms a ring (the Z-ring) at the future site of the septum, the division site. This ring is crucial for recruiting other proteins that will help in the division process. ○ Constriction and Invagination: The Z-ring contracts, leading to the formation of a septum. 4. Completion of Cell Division: ○ Septum Formation: The septum is completed, dividing the cytoplasm and the chromosomes into two separate ○ Separation of Daughter Cells

Question 41

3 big steps of eukaryotic cell cycle

Answer 41

Interphase M phase (Mitosis) Cytokinesis

Question 42

Interphase

Answer 42

-G1 phase: Cell growth and normal metabolic processes, increases in size and prepares the necessary proteins and organelles for DNA synthesis. -S Phase: : DNA replication. Each chromosome is duplicated, resulting in two sister chromatids held together by a centromere -G2 Phase: Further cell growth and preparation for mitosis. The cell produces proteins and organelles necessary for cell division.

Question 43

Mitosis

Answer 43

-Prophase: Chromosomes condense and become visible. The nuclear envelope begins to break down. The mitotic spindle starts to form. -Metaphase: Chromosomes align at the metaphase plate (the cell’s equator). Spindle fibers attach to the centromeres of the chromosomes -Anaphase: Sister chromatids are pulled apart toward opposite poles of the cell by the spindle fibers -Telophase: Chromosomes arrive at the poles and begin to de-condense. The nuclear envelope re-forms around each set of chromosomes, creating two separate nuclei

Question 44

Cytokinesis

Answer 44

Division of the cytoplasm to form two daughter cells. This process usually begins during telophase and completes shortly after Mechanism: -Animal cells: contractile ring that pinches the cell in two -Plant cells: cell plate forms along center line of cell => formation of new cell wall