Cells Flashcards

Question

Internal Cell Structure + Functions Golgi Apparatus

Answer 1

Cell transport for lipids and proteins from the endoplasmic reticulum to other parts of the cell

Answer 2

Storage vessels with enzymes for breakdown of amino acids and fatty acids + detoxifying substances like hydrogen peroxide

Answer 3

Storage vessels for enzymes such as lysozyme for the digestion of old organelles or foreign matter (like bacteria)

Answer 4

A general term used for a fluid-filled structure used in cell digestion + transport

Answer 5

Located in the cell, they allow attachment and separation of duplicate chromosomes during cell division (*+ forms centrosome which organises microtubules and create spindle fibres)

Answer 6

Located on the outside of some cells, they move liquid past the cell surface. For example, in the trachea in combination with mucus they are whip-like cellular extensions that move substances along the cells surface the only example of flagella cell in humans are sperm (tails), and this propels sperm where cilia propel other substances along the cells

Answer 7

Outer membrane structure in the form of cell protrusions, creating increased surface area, such as for absorption of nutrients in the digestive tract found in active absorption (intestinal and kidney) core of actin filaments extend into the cytoskeleton

Answer 8

The cell to cell adhesion point

Answer 9

Connection point that allows ions, other molecules and electrical impulses directly between cells

Answer 10

Cells outer border - formed by a phospholipid bilayer membrane controls waht enters/exits the cell. Is semi-permeable maintains cell structure and shape

Answer 11

The cytoskeleton of a cell provides structural support for the cell membrane; the cytoskeleton consists of microfilaments such as actin - ***It is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms.****

Answer 12

The liquid component of the cells that houses all of the organelles ****It fills the space between the plasma membrane and the nucleus Cytosol is the semi-transparent fluid that suspends the elements Numerous small structures are part of the cytoplasm along with the fluid that acts as the interior environment of each cell Structures are called organelles (little organs) Cytoskeleton (cell skeleton) threadlike structures to hold organelles in place**** from later in the slides

Answer 13

Control centre of the cell - the main internal structure of the cell. ***The nucleus houses the cells genome/DNA and genetic information in the form of chromosomes (which carry the genetic code) and controls cellular activities (MRS C GREN)

Answer 14

A site within the nucleus that forms Ribsome subunits for the production of protein

Answer 15

The nuclear membrane is the membrane that surrounds the nucleus. The nuclear pores are small gaps in the nuclear membrane. ***They function to regulate the selective passage of molecules (like proteins and RNA) between the nucleus and cytoplasm***

Answer 16

'Cell powerhouse' for the production of energy in the form of ATP (adenosine triphosphate) using cellular aerobic respiration. ***The mitochondria is also in charge for regulating cell metabolism, generating heat, storing calcium, and helping with cell signalling and apoptosis (programmed cell death).***

Answer 17

Produces phospholipids for the cells outer membrane

Answer 18

Contains rRbosomes (the 'rough' spots on its surface) for protein production. ****It helps synthesize and transport proteins, which are made by the ribosomes attached to its surface. It also plays a role in folding and modifying proteins.****

Answer 19

Produce proteins from RNA (ribonucleic acid). ***Ribosomes synthesize proteins by assembling amino acids according to the instructions in messenger RNA (mRNA).*** ****Protein synthesis is the process by which cells create proteins. It involves two main stages: Transcription: In the nucleus, a segment of DNA is used to create a complementary strand of mRNA (messenger RNA). Translation: The mRNA travels to the ribosomes in the cytoplasm, where it is read, and the ribosomes assemble amino acids into a specific protein chain based on the mRNA's sequence. tRNA (transfer RNA) brings the correct amino acids to the ribosome, and rRNA (ribosomal RNA) helps form the ribosome's structure and catalyzes the assembly of amino acids into proteins.****

Answer 20

Cell transport for lipids and proteins from the endoplasmic reticulum to other parts of the cell. ***The Golgi apparatus transports proteins and lipids to various destinations within the cell, including: Plasma membrane: For secretion or incorporation into the cell membrane. Lysosomes: For digestion and breakdown of cellular materials. Vesicles: That transport materials to other organelles or out of the cell (e.g., through exocytosis). The Golgi helps sort and package molecules for specific functions and destinations.***

Answer 21

Storage vessels with enzymes for the breakdown of amino acids and fatty acids. ***Peroxisomes also function for detoxification of harmful substances (such as hydrogen peroxide), and the production of certain lipids. They contain enzymes that help neutralize reactive oxygen species (ROS) and convert hydrogen peroxide (H₂O₂) into water and oxygen.**

Answer 22

Storage vessel for enzymes (such as lysozyme) for the digestion of old organelles or foreign material (like bacteria/virus). ***Lysosomes help with breaking down waste, cellular debris, and harmful substances using digestive enzymes. They help with recycling cellular components, and maintaining cellular health through autophagy (self-digestion of damaged organelles).***

Answer 23

A general term for a fluid filled structure used in cell digestion. ***A vesicle is a small, membrane-bound sac that transports, stores, or digests substances within a cell. Functions of Vesicles: Transport – Move proteins, lipids, and other molecules between organelles or to the cell membrane for secretion. Storage – Hold nutrients, waste, or enzymes until needed. Digestion – Some vesicles, like lysosomes, contain digestive enzymes to break down waste and harmful substances. Vesicles act as cellular “containers”, shuttling materials where they are needed.***

Answer 24

Located in the cell cytoplasm (specifically in the centrosome near the nucleus), and a cylindrical shape made up of microtubules, centrioles allow attachment and separation of duplicate chromosomes during cell division by creating the miotic spindle. ***Cell Division – During mitosis and meiosis, centrioles help form the mitotic spindle, which separates chromosomes. Microtubule Organization – They help organize the cytoskeleton, providing structural support to the cell. Cilia & Flagella Formation – Centrioles give rise to basal bodies, which are essential for forming cilia and flagella, used for movement.***

Answer 25

Located on the outside of some cells, cilia move liquid over the cell surface (e.g mucus moving through the trachea). *** Cilia also help cells to move through liquids, move fluid over cells, and some cilia can act as sensory structures, detecting signals like sound or chemical changes***

Answer 26

Outer membrane structure in the form of cell protrusions. They create an increased surface area for increased absorption (e.g absorption of nutrients in the digestive tract).

Answer 27

The cell junction/desmosome is the cell to cell adhesion point. ***This means they connect neighbouring cells, preventing them from pulling apart. This is common in tissues with a lot of mechanical stress (e.g skin, heart muscle). They link to cytoskeleton connection, as they link to intermediate filaments; reinforcing the cells structure and integrity**

Answer 28

Connection point that enable communication between cells by allowing ions, other molecules and electrical impulses directly between cells. Found in the plasma membrane of the cell (much like the desmosome/cell junction).

Answer 29

The plasma membrane is a flexible, fragile and transparent barrier that contains the cell contents and separates them from the surrounding environment. ***The plasma membrane is structured as a phospholipid bilayer. 2 lipid layers (can be phospholipds or cholesterol) are arranged 'tail to tail', with hydrophillic heads facing outward (internally and externally to the cell), and hydrophobic tails facing inward. Protein molecules 'float'/are embedded in the membrane. These are not rigidly fixed and are fluid to move sideways within the bilayer - giving the membrane a fluid like consistency. Some proteins are found spanning across it (integral proteins) and others attached to the surface (peripheral proteins). These proteins have various functions, including transport, signaling, and structural support.***

Answer 30

Membrane lipids are a basic component of the cell membrane. They are responsible for the structural integrity of the cell membrane. Membrane lipids are structures in a phospholipid bilayer. The Polar heads of the lipid layer are hydophillic - lining both the intra/extracellular surfaces. The polar tails are hydrophobic, and they line the interior of the membrane. The bilayer serves as a barrier to the diffusion of water and hydrophillic substances such as glucose, while allowing lipid-soluble molecules (such as oxygen and carbon dioxide) to diffuse through it readily.

Answer 31

Plasma membrane proteins are responsible for the most specialised functions of the membrane: receptors for hormones, chemical messengers and binding sites for anchoring the cell to other structures. The three membrane proteins include the following: 1 - Integral/Intrinsic Membrane Proteins/IMP (embedded in the plasma membrane) - These proteins include transport (carrier/channel) proteins. Channel proteins cluster together to form pores/protein channels that allow water or water soluble molecules (e.g ions) to pass through, and enable signals from hormones and chemicals to be transmitted inside the cell. Carrier membranes bind and transport substances across the membrane surface; changing shape to do so before reverting back to their original shape.

Answer 32

1 - Solutions: (A homogenous mixture of two or more components) - e.g Interisital, Intra/Extracellular fluids 2 - Solvents: (Has the ability to dissolve other substances) e.g Water 3 - Solutes: (Smaller components or substances) e.g Ions, Nutrients (glucose, amino acids), Gases (O2, CO2) 3 - Intracellular Fluid solution (Nucleoplasm and Cytosol) – solution containing small amounts of gases, nutrients and salts dissolved in water 4 - Intersitial Fluid solution (Exterior of cells) – solution containing rich nutritious (amino acids, sugars, fatty acids, vitamins) fluid, contains hormones, neurotransmitters, salts and waste products SUMMARY: Water is the solvent in biological systems. Ions, nutrients, gases, and waste products are solutes. The mixture of water (solvent) and these solutes forms a solution (e.g fluids) that can be transported across the plasma membrane via various transport mechanisms.

Answer 33

INTRO TO TRANSPORT - NO BACK OF CARD

Answer 34

Passive transport is the movement of substances from an area of high concentration to an area of low concentration across a semi-permeable membrane (e.g cell membrane) It does not require energy It instead relies on concentration and pressure gradients Occurs through a semipermeable membrane ***Example of passive transport include: Diffusion, Facilitated diffusion (larger molecules involving membrane proteins to help move them), Osmosis (diffusion of water using specialised channels called aquaporins)***

Answer 35

Filtration is an example of passive transport in the body, where water and solutes move due to a greater force/pressure (hydrostatic pressure) on one side of the membrane. The pressure gradient is high to low pressure. Facilitated diffusion can also be called carrier mediated facilitated diffusion, where substances such as electrolytes and glucose cannot pass (too large) directly through the cell membrane without facilitation. The IMP transport the substances via a specific channel (carrier) used as a note in the slides An example of hydrostatic pressure in the body is the vascular system. Blood pressure is generated in the vessels when the heart contracts. The blood reaching the capillary bed has a hydrostatic pressure sufficient to force water across the thin capillary membranes into the spaces between the cells (Intersitial spaces).

Answer 36

Osmosis is the movement of water from an area of high concentration to an area of low concentration across a semi-permeable membrane (concentration gradient). The membrane must be more permeable to water than to solutes Concentration of solutes must be greater, so that water moves easily for efficient diffusion Osmosis controls the distribution and movement of water between body compartments Osmosis is vital for maintaining normal fluid balance

Answer 37

Active transport is the movement of substances against/up their concentration gradient, from an area of low concentration to an area of high concentration across a semi-permeable membrane using ATP/energy. Is similar to carrier mediated Facilitated diffusion Requires protein carriers (solute pump) that combine with substances to be transported across the membrane ***from slideshow notes***The best-known pump is the sodium–potassium (ATP) pump , which continuously pumps sodium and potassium against their concentration gradient to maintain ionic concentration gradients vital for nerve conduction and homeostasis. The important aspect is that ATP is required, which means that when energy is available the pump works, but when ATP is depleted, such as during disease, the pump will not be as efficient.

Answer 38

Some larger substances cannot get through the plasma membrane with passive OR active transport. Vesicular transport requires help from ATP. This includes processes such as: exocytosis (cell expels substances to external environment) and endocytosis (cell engulfs substances from external environment)

Answer 39

Exocytosis is the process by which a cell expels substances by fusing a vesicle with the plasma membrane, releasing its contents outside the cell. This is how cells secrete materials like hormones, neurotransmitters, and waste.**** Cells actively secrete hormones, mucus and other cell products/waste in a vesicle

Answer 40

Endocytosis is the process by which a cell engulfs substances from its external environment by forming a vesicle from the plasma membrane. This allows the cell to take in large molecules, fluids, or even other cells.**** moves substances INTO the cell

Answer 41

Mitosis is the process in which a single eukaryotic cell divides to produce two genetically identical daughter cells, each with the same number of chromosomes as the original cell. Mitosis is used to produce more cells for growth and repair

Answer 42

Cell Cycle Overview The cell cycle consists of interphase and mitosis. Interphase is divided into three phases: G₁ (Gap 1), S (Synthesis), and G₂ (Gap 2). 90% of the cell cycle is spent in interphase Mitosis comes after interphase, and is then followed by cytokinesis in the last two stages of mitosis. 1. Interphase (Before Mitosis) G₁ Phase (Gap 1): The cell grows, carries out normal functions, and synthesizes proteins necessary for growth and metabolism. When: The first phase of interphase. Protein Synthesis: Occurs actively here as the cell prepares for DNA replication and mitosis. S Phase (Synthesis):DNA replication occurs ONLY here, ensuring that the cell’s genetic material is copied. Second phase of interphase Protein Synthesis: Continues in this phase, though its focus shifts to producing proteins for DNA replication and mitosis. G₂ Phase (Gap 2):The final phase of interphase, after DNA replication. The cell prepares for mitosis by synthesizing additional proteins and checking the DNA for errors. Protein Synthesis: Continues here, focusing on preparing the cell for mitosis. 2. Mitosis (Cell Division) Prophase: First stage of mitosis. Chromosomes condense, and the nuclear envelope breaks down. Protein Synthesis: Protein synthesis slows down during mitosis, but it may still occur for certain structural proteins needed for division. Metaphase: Second stage of mitosis. Chromosomes align in the middle of the cell. Anaphase: Third stage of mitosis. Sister chromatids are pulled apart to opposite sides of the cell. Telophase: Fourth stage of mitosis. New nuclear envelopes form around the separated chromosomes, and the cell prepares to divide. Cytokinesis: Occurs during late anaphase stage/into telophase. The cytoplasm divides, forming two daughter cells.

Answer 43

DNA Replication DNA helix uncoils, separates into its 2 nucleotide chains: This describes the initial step in DNA replication. The DNA double helix unwinds and separates into two single strands. Each chain serves as a template: Each single strand of DNA serves as a template to build a new complementary strand. This process occurs during the S phase of interphase before cell division (mitosis or meiosis). The goal of DNA replication is to ensure that each new cell gets an identical copy of the DNA.

Answer 44

Transcription - Nucleotides join in a complementary way – A & T, G & C (transcription): This describes transcription, where a messenger RNA (mRNA) molecule is synthesized using one strand of DNA as a template. Base pairing occurs (A with T, G with C), but with RNA, A pairs with U (uracil) instead of thymine. Transcription creates mRNA and DNA: During transcription, an mRNA transcript is produced from the DNA template. The mRNA carries the genetic code from the DNA in the nucleus to the ribosomes in the cytoplasm. Transcription occurs in the nucleus. Translation - Code in mRNA transcript allows ribosomes to synthesize proteins: This describes the process of translation. The mRNA leaves the nucleus and enters the cytoplasm, where ribosomes read the mRNA sequence and use it to build a protein. Translation – amino acid building: In translation, the ribosomes read the mRNA codons (groups of three nucleotides) and assemble the corresponding amino acids into a polypeptide chain (protein). Translation occurs in the cytoplasm at the ribosomes.

Answer 45

Mitosis and Cytokinesis

Answer 46

The process whereby a single parent cell divides to create two genetically identical daughter cells, each with the same number of chromosomes as the original cell

Answer 47

Prophase Metaphase Anaphase Telophase

Answer 48

Prophase is the first stage of mitosis In this phase, chromatin condenses down into visible chromosomes (where the chromatids are attached at the centromere) Spindle fibers appear in this phase of mitosis (later used to seperate chomosomes during cell division) The nucleolus and nuclear envelope/membrane disappear

Answer 49

The second stage of mitosis is Metaphase In this phase, chromosomes align at the centre of the cell (the cells' equator) The spindle fibres attach to the centromeres of each chromosome

Answer 50

The third stage of mitosis is Anaphase In this stage, the centromeres break apart, and sister chromatids are pulled apart by spindle fibers Chromosomes move away from the centre of the cell The cleavage furrow appears in this stage (beginning of split)

Answer 51

The fourth stage of mitosis is telophase In this stage, a new nuclei is formed around each of the the seperated chromatids + a new nuclear membrane/envelope for each new cell Chromosomes decondense back into chromatin (so the cell can continue to work as normal) + the spindle fibres disappear The cytoplasm and organelles divide equally into each cell The process of cell division is completed

Answer 52

Cytokinesis usually begins late into the anaphase of mitosis (third stage), and completes during telophase (fourth stage)

Answer 53

Cytokinesis is one of the steps of mitosis

Answer 54

During cytokinesis, a contractile ring forms a cleavage furrow over the midline, eventually squeezing the original cytoplasm into two parts The contractile ring is made of protein microfilaments, and forms just below the plasma membrane, this then creates the cleavage furrow over the midline of the spindle It shrinks, pinching the plasma membrane inward until it separates into 2 distinct cells

Answer 55

Meiosis is a type of cell division that creates four genetically unique gametes (sperm or egg cells), each with half the chromosome number of the original cell

Answer 56

Meiosis is essential for sexual reproduction, and genetic diversity through gene shuffling

Answer 57

Structure Provide structural support for cells, connective tissue e.g. collagen Transport Proteins transport molecules across cell membranes and throughout the body Communication Proteins allow cells to communicate with their environment by binding to signalling molecules DNA DNA associated proteins regulate chromosome structure during cell division and or play a role in regulating gene expression Enzymes Proteins act as enzymes that catalyse chemical reactions Cell division Proteins control cell division Metabolism Proteins control metabolism pH balance Proteins help maintain proper pH balance in the blood Signal transduction Proteins allow cells to respond to cues by changing their levels localisation activity and interactions

Answer 58

cell membrane enfolds substances and encloses them in a small membranous vesicle This then detaches from the cell membrane and moves into the cystol (fluid portion of the cytoplasm)

Answer 59

Pinocytosis (cell 'drinking') - ingestion of fluids and solute molecules through small vesicles Phagocytosis (cell 'eating') - ingestion of large particles (e.g bacteria) through large vesicles

Cells Flashcards

(84 cards)