IB Biology Unit 1

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Unit 1: Cell iology

67 Terms

1

Cell Theory:

  1. All living things are made up of cells

  2. cells are the smallest units of life

  3. cells come from preexisting cells

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2

Exceptions to cell theory and why

  1. Aseptate Fungal Hyphae: continuous cytoplasm, does not have septa

  2. Muscle Fibres: multinucleated and have 1 continuous plasma membrane

  3. giant algae: large unicellular organism

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3

How do you calculate magnification

M = I/A

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4

Define emergent Properties

Arise from the interaction of individual components in a complex system

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5

Define cell differentiation

Newly formed cells have the ability to differentiate and become specialized. They all have an identical genome and the expression of certain genes makes them differenciate.

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6

Gene Packing of active genes:

packaged in euchromatin for transcription

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7

Gene packaging of inactive genes

packaged in heterochromatin

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8

What are stem cells?

Unspecialized cells

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9

key qualities of stem cells

Self renewal —> they can continuously divide/replicate

Potency —> differentiate into any specialized cell

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10

what are totipotent stem cells?

Found in the embryo and can specialize into anything (T = furthest in the alphabet so the cells can specialize further into anything)

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11

what are pluripotent stem cells?

Found in the embryo, can specialize into nearly anything and are research useful (pluri = multiple)

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12

Applications for pluripotent stem cells:

Parkinson’s disease: nerve cells

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13

what are multipotent stem cells?

derived from adult stem cells limited range of differentiation (Multi —> more —> more years old)

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14

Applications for multipotent stem cells

Can be used to treat leukaemia: Bone marrow can specialize into any type of blood cell

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15

What are unipotent stem cells?

adult stem cells, can only divide into the same type of cell (uni = 1)

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16

Applications for unipotent stem cells:

Used to treat burn victims: skin cells can make more skin cells

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17

Stargard’s Disease

Genetic, progressive blindness: embryonic stem cells are applied to retinal cells

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18

Artificial stem cell techniques: somatic cell nuclear transfer

creation of embryonic clones by fusing a diploid nucleus w/ an enucleated egg

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19

Artificial stem cell techniques: Nuclear reprogramming

Induce a change in gene expression of a cell so it can differentiate into a desired cell

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20

Light microscopes

they can view living things

they have a lower magnification

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21

Electric Microscopes

High magnification

they can only view dead specimens

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22

Draw and label a prokaryotic cell

Pili

70 S ribosomes

Nucleoid

Plasmid

Slime capsule

Cell wall

Cell membrane

<p>Pili</p><p>70 S ribosomes</p><p>Nucleoid </p><p>Plasmid</p><p>Slime capsule</p><p>Cell wall </p><p>Cell membrane</p>
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23

Functions of components of a prokaryotic cell:

Pili

70 S ribosomes

Nucleoid

Plasmid

Slime capsule

Cell wall

Cell membrane

Pili: helps with adhesion

70 S ribosomes: sites for protein synthesis

Nucleoid: contains a singular strand of DNA

Plasmid: small independent DNA

Slime capsule: Made of polysaccharides

cell wall: maintains shape

cell membrane: controls what enters and leaves the cell

flagellum: works as a motor

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24

how do prokaryotic cells divide?

Binary fission:

  1. A circular strand of DNA is copied in the cell

  2. 2 DNA loops attach to membrane

  3. membrane elongates and pinches off through cytokinesis

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25

What is the difference between a eukaryotic cell and a prokaryotic cell?

Eukaryotic cells:

compartmentalized

mitochondria

chloroplasts

double membrane

nucleus

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26

Parts of a eukaryotic animal cell and their functions

cell wall: maintains shape

cytoplasm: medium for chemical reactions

80 S ribosomes: protein synthesis

ER: membrane network

  • RER: protein synthesis

  • SER: creation/storage of lipids

Golgi body: storage/processing proteins

mitochondria: energy

nucleus: DNA storage

Lysosome: sac w/ enyzmes

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27

Parts of a eukaryotic animal cell and their functions

cell wall: maintains shape

80 S ribosomes: protein synthesis

ER: membrane network

  • RER: protein synthesis

  • SER: creation/storage of lipids

Golgi body: storage/processing proteins

mitochondria: energy

nucleus: DNA storage

vacuole: hydrostatic pressure

chloroplasts: site of photosynthesis

cell wall: external covering

cytoskeleton: boning/structure

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28

draw and label a eukaryotic animal and plant cell

knowt flashcard image
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29

Fluid Mosaic Model:

knowt flashcard image
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30

Functions of phospholipids:

Amphipathic

polar head: hydrophilic

non-polar tail: hydrophobic

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31

Function of Channel Proteins

transmembrane protein:

  • passive transport of ions at a fast rate

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32

Function of glycoproteins

transmembrane protein:

  • alter their shape to translocate solute, active transport

(G for glyco: G for gemini —> change)

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33

Functions of integral proteins

Transmembrane protein:

  • keep toxins out

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34

Functions of peripheral proteins

temporarily attached:

  • lies on the surface of the membrane

  • cellular communication and binding site for carbohydrate

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35

carbohydrate:

Binding point and identifies the cell

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36

cholesterol:

stabilizes the membrane, amphipathic, reduces the fluidity of the membrane and prevents crystallization.

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37

Davson Danielli

phospholipids sandwiched between a layer of proteins on each side

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38

Membrane transport: Passive transport

goes along the concentration gradient and is divided into: facilitated diffusion, osmosis and simple diffusion

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39

Facilitated diffusion:

Through channel proteins, large/polar molecules move

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40

simple diffusion:

movement of small particles from high concentration to low

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41

osmosis:

net diffusion of H2O —> from low solute concentration to high

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42

active transport is divided into:

direct and indirect

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43

what is indirect:

indirectly uses energy: coupling molecules —> a molecules using another molecules ATP (Piggy backing)

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44

what is direct:

a molecule using its on ATP

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45

what factors affect diffusion?

temperature, molecule size, gradient steepness

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46

what is vesicular transport

Substances are transported within a cell in membrane-bound vesicles.

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47

Hypertonic

too much solute outside so water escapes the cell and makes it shrivel

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48

hypotonic

there is too much solute in the cell so water enters and makes it bulge

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49

isotonic

balanced osmolarity

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50

sodium potassium pump:

active transport: 3 sodiums leave the cell while 2 potassiums enter through the SP pump

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51

Endosymbiotic theory

1 prokaryotic cell engulfed another and engulfed mitochondria and chloroplasts

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52

evidence for endosymbiosis

MAD DR

Membrane: double membrane

Antibiotic resistance: bacterial origin

Division: similar to binary fission

DNA: naked and circular

Ribosomes: 70 S ribosomes in chloroplasts and mitochondria

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53

eukaryotic cell division

Cell cycle:

interphase

  • making DNA

  • Cellular functions

G1: cel is growing and producing more cytoplasm

S: Synthesis, DNA is replicated

G2: cell prepares for division

Mitosis

Cytokinesis

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54

Steps of mitosis

PMAT

Prophase: chromosomes supercoil, microtubules grow on opposite sides

Metaphase: Spindle fibres grow, attach to the centromere, and chromosomes align in the middle

Anaphase: spindle fibers pull sister chromatids apart

Telophase: spindle fibers are dissolved and nuclear membranes form around each cell

cytokenisis: microtubule breaks the cell in 2

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55

What are the cell checkpoints:

G0: resting state after cell divides

G1: checks nutrients, growth factors and DNA for damage

G2: check size and error in DNA replication

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56

Mitotic index calculation

cells in mitosis/ number of cells

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57

Necrosis

Murder: an injured cell, lacks nutrients, has toxins

  • cell swells —> increases in osmotic pressure

  • cell bursts —> can cause damage in surrounding cell

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58

Apoptosis

Cell suicide: necessary death because of mutations

  • cell contents are repackaged

  • cell shrinks + breaks down into apoptotic bundles

  • apoptotic bodies are engulfed

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59

Cancer: what are metasis

cells from primary to secondary structure

  1. tumour can invade other tissue

  2. can travel into blood supply

  3. invade healthy cells and start dividing

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60

How does smoking increase chances of cancer?

strong positive correlation between both:

  • 4000 chemicals —> 600 are carcinogenic

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61

normal cell vs cancer cell

normal cell:

  • small cytoplasm

  • regulated division

  • clear structure

Cancer cell:

  • large cytoplasm

  • irregular/rapid division

  • unclear structure

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62

mutagens: what are they?

Mutated genes: changes in the genetic sequence

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63

What causes mutagens:

exposure to ultraviolet waves

x rays

viruses like hepatitis

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64

what are oncogenes?

genes with potential to cause cancer

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65

Pro-oncogenes, what are they?

stimulate growth/cell cycle, can make it very rapid and irregular

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66

tumor repressor genes:

repress the cell cycle, apoptosis

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67

what happens if tumor repressor genes stop working?

higher risk for cancer

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