Week 2 content: Cells

Question 1

what is a cell

Answer 1

cell are the building blocks of all living organisms
cells can only be created from pre-existing cells, this occurs in interphase, G1, where cells grow, replicate DNA and organelles, preparing for separation

Question 2

what are the two cell types

Answer 2

Eukaryotes and Prokaryotes

Question 3

what is a Eukaryotic cell

Answer 3

a type of complex cells that contain a nucleus and organelles contained within a plasma membrane

Question 4

what is a prokaryotic cell

Answer 4

a small, single-cell organism (bacteria), that lacks a nucleus and membrane bound organelles

Question 5

what are some cell types in human bodies

Answer 5

• red blood cells
• epithelial cells
• skeletal muscle cells
• nerve cells

Question 6

name the components and organelles in eukaryotes
(15)

Answer 6

• nucleus
• ribosome
• mitochondria
• Golgi complex
• vacuole
• cytoplasm
• lysosome
• plasma membrane
• centriole
• cilia
• cytoskeleton
• protein fibres
• endoplasmic reticulum (rough and smooth)
• microvilli

Question 7

what are the different types of protein fibers found in a cell

Answer 7

• microfilaments: smallest and are part of the cytoskeleton, they are important for muscle contraction and cell movement. Made of polymers of actin.
  intermediate filaments: found inside cell, responsible for stability and organisation of organelles
  microtubules: provide cell shape, help move organelles, separate chromosomes during cell division

Question 8

what do each of these organelles do

Answer 8

cell membrane:
- a barrier between inside and outside of cell.
- regulates what substances enter and exit the cell
- allows communication between cells
nucleus:
- found within the nucleus envelope
- contains pores in membrane
- contains DNA, genes code for proteins
- nucleolus produces ribonucleic acid
Cytoskeleton: a network of protein fibers that provide structural support and movement.
microvilli: small, finger-like projections found on cells surface, increases SA
mitochondria:
- production of ATP
- contains its own DNA (mDNA)
- mDNA contains 37 genes that code for ATP production
Endoplasmic reticulum:
- smooth: no ribosomes, makes and stores lipids and steroids, makes cellular material, detoxifies, stores calcium for cell signaling
- rough: covered in ribosomes, produces proteins that when released into the lumen (small spaces inside rER) are folded and modified until functional
Golgi complex:
- receives products from rER
- releases products into plasma membrane or out of cell
lysosomes:
- contain digestive enzymes
- have a low pH
- breakdown of damaged cells and bacteria
- lysosomes fuse to cell membrane to eject unwanted components

Question 9

what is the cell membrane made up of

Answer 9

• lipid membrane made of phospholipids
• proteins

Question 10

what proteins are found in the phospholipid membrane of cells

Answer 10

• channel proteins allow movement of water substances through the membrane
• integral proteins: span through the entire membrane, from external layer to internal
• peripheral proteins: slightly embedded in membrane
  -glycoproteins: made up of a carbohydrate bound to protein (receives messages)

Question 11

what are examples of integral proteins

Answer 11

• ion channel and carrier proteins: create channels to transport ions and substances
• receptors: communication between cells
• some enzymes: break down substances
• some linker proteins: anchor, provide structural stability

Question 12

what are examples of peripheral proteins

Answer 12

• some enzymes
• cell identity markers: recognition of your own body’s cell

Question 13

what are the two categories of membrane transport

Answer 13

passive (doesn’t require energy) and active (requires energy)

Question 14

what are the seven (7) types of membrane transport

Answer 14

• diffusion
• facilitated diffusion
• osmosis
• active transport
• vesicular transport
• endocytosis
• exocytosis

Question 15

what is diffusion

Answer 15

• movement of substance from an area of high conc. to an area of low conc.
• does not require energy
• rate of diffusion is influenced by:
• distance,
  *size of molecules, *temperatures,
  *steepness of conc. gradient (larger conc. gradient = faster diffusion),
  *electrical forces within cells (more -ive charge in cells = faster diffusion for positively charged ions)
  eg CO2 and diffusion (the product of ATP production)
• excess CO2 in cells = high conc. gradient.
• CO2 moves from area of high to low conc. - out of cell
  cell interior–> interstitual fluid–> bloodstream –> lungs –> exhaled

Question 16

what is osmosis

Answer 16

movement of water across cell membrane by diffusion
- area of high conc of solutes –> area of low conc. solutes
- high water levels in cell = low conc. of solutes
- low water levels outside cell = high solute conc.
- even levels of solute conc. inside and outside of cell = no net movement of water

Question 17

what is facilitated diffusion

Answer 17

ions and polar/ionic molecules cross in or out of cells via channel or carrier proteins

Question 18

what is active transport

Answer 18

• can transport solutes without conc. gradient
• requires ATP
• involves ion pumps to transport ions such as Na+, K+, and Ca2+

Question 19

what is vesicular diffusion

Answer 19

use of fluid filled sacks that move material into or out of cell

Question 20

what is endocytosis

Answer 20

• a type of vesicular transport for entry of material into cell
• cell membrane invaginates and collects molecules
• encloses over molecules creating a sack.
• material is moved into cell

Question 21

what is exocytosis

Answer 21

• a type of vesicular transport used to remove molecules from the cell
• material is collected and enclosed within a vessel in the cell
• vessel fuses to cell membrane
• cell membrane moves apart to release contents

Question 22

what happens to human cells in solution?

Answer 22

hypertonic solution: having greater conc. of solutes and less water than another solution. E.g. high conc. of sodium ions outside a cell and low conc. inside the cell cause the cell to release water to dilute the solution outside, causing it to shrink
hypotonic: low solute conc. and more water than another solution. E.g. a cell placed in water = more Na+ ions inside the cell compared to outside and less water
- causes water to move into cell to dilute Na+ ions, causes cell to swell, and potentially burst
isotonic: concentrations of water and ions are the same inside and outside of cell. No net movement, the cell and its environment are at equilibrium.

Question 23

what solution is used to treat dehydration or used in a saline drip, why?

Answer 23

isotonic solutions
- does not affect the cells volume or structure
- increases the amount of extracellular fluid

Question 24

what is extracellular fluid

Answer 24

a fluid found outside of cells

Question 25

what is intracellular fluid. How does it differ from the cytoplasm and cytosol

Answer 25

Intracellular fluid is found inside the cell. It is essentially the same as the cytoplasm, however, the cytoplasm encompasses all the cell contents within the cell membrane. the cytosol is the liquid portion of the cytoplasm

Question 26

what are the major types of cell division

Answer 26

mitosis and meiosis

Question 27

what is involved in mitosis

Answer 27

division of a parent cell into two daughter cells. Each daughter cell contains the same genetic material as the parent (46 chromosomes, 23 pairs)

Question 28

what is involved in meiosis

Answer 28

division of a cell into four daughter cells, containing half the number of chromosomes to the parent this is necessary for reproduction

Question 29

what are the major phases in the cell cycle (two) in mitosis

Answer 29

Mitotic phase and interphase

Question 30

breakdown the phases in the cell cycle

Answer 30

Mitotic phase = prophase, metaphase, anaphase, telophase, cytokinesis interphase = G1, G0, S and G2

Question 31

draw the phases and what occurs within each phase

Answer 31

interphase - G2 = growth and centromere replication - S = DNA replication - G0 = some cells exit the cell cycle for no further replication - G1 = the first stage of mitosis, duplication of organelles mitotic phase - prophase = chromosomes duplicate and coil, become visible. centrosomes divide and position at opposite ends of cell, spindle fibers begin to extend from each end - metaphase = chromosomes align along the metaphase plate, spindle fibers attach to kineticore - anaphase = sister chromatids split and are pulled by microtubules to opposite cell ends - telophase = nuclear envelope reforms, chromosomes uncoil, nucleoli reappears, indentation in cytoplasm (cleavage furrow) - cytokinesis = division of daughter cells

Question 32

what are different cells lifespans

Answer 32

Neutrophils = hours to days skin cells = 2-3 weeks

Question 33

what is DNA and what is DNA replication

Answer 33

DNA is the genetic material that codes for the functions of a cell. DNA is made up of different genes, each gene consists of nitrogenous bases grouped into codons (3 bases), and each gene is responsible for coding a certain protein

Question 34

what is DNA replication

Answer 34

DNA replication is when the parent DNA helicase separates, producing exact copies of its DNA so that each daughter cell produced contains the same information

Question 35

what makes up a nitrogenous base

Answer 35

on a DNA strand - adenine - thymine - guanine - cytosine On RNA strand - adenine - uracil - guanine - cytosine

Question 36

what are the mitotic phases (four stages) and cell division phase

Answer 36

- prophase - metaphase - anaphase - telophase Cell division = cytokinesis

Question 37

where are checkpoints in the cell cycle (3)

Answer 37

- G2 = cell size and correct DNA replication - Mitotic phase = chromosomes attachment to spindles - G1 = DNA damage

Question 38

what are proteins made up of

Answer 38

long polymer chains of amino acids

Question 39

Explain the role of proteins in a cell

Answer 39

different cells = different proteins determine - molecule transport - cellular signaling response - enzyme production --> metabolic pathways - structural layout of cell

Question 40

how do proteins produced in the ER get exported outside of the cell

Answer 40

as proteins pass through the ER to the Golgi apparatus and from the Golgi apparatus to the outside of the cell, they are modified. modified proteins are transported by vesicular transport or progressive maturation to the outside of the cell. Some proteins are transported to lysosomes or plasma membrane

Question 41

what is the role of proteins outside of a cell?

Answer 41

repair immunity pH energy fluid balance

Question 42

what is a genome

Question 43

what does a gene code for

Question 44

explain the structural breakdown of DNA in a cell

Question 45

what are the main components of genes

Question 46

define each region and its role

Question 47

what is transcription, where does it occur and what does it produce

Question 48

what is translation, where does it occur and what does it produce

Question 49

What are the different types of DNA

Question 50

what are the components of RNA

Question 51

what are the four/five nucleic acid bases

Question 52

what determines the production of certain proteins

Question 53

what is a codon and an anticodon

Question 54

what codons codes for stop

Question 55

what codon codes for start

Question 56

what is protein synthesis

Question 57

in protein synthesis, what types of RNA is involved

Question 58

what are the three main steps in protein synthesis

Question 59

how is DNA packed

Question 60

what are the components of a ribosome

Question 61

what is the purpose of a ribosome

Question 62

what enzymes are used in protein synthesis and what is their role

Question 63

when does a protein become functional

Question 64

what bonds hold amino acids together