Biology - Semester review

Cell

The basic unit of structure and function in living things

cell theory

1. All living organisms are composed of one or more cells.
2. The cell is the basic unit of structure and organization in organisms.
3. Cells arise from pre-existing cells.

cell wall

Tough, flexible, rigid
Only in plants cells
For structural support, protection, filtering mechanism and pressure vessel, preventing over-expansion
Contains cellulose (C6H10O5)

Rough ER

tubular transport network for molecules targeted for certain modifications and final destinations
Produces proteins
Fused to nuclear membrane
Ribosomes attached to it.

Smooth ER

synthesizes lipids, phospholipids as in plasma membranes, and steroids

Glogi Apparatus

modifies molecules and packages them into vesicles to sent elsewhere
temporary storage
chemical reactions and lipid synthesis take place here

vesciles

small membrane bound sacs used to move chemicals to other locations

Lysosomes

Contain digestive enzymes to break up waste and debris.
Fuse with vacuoles to digest their contents
found in animal cells
in yeast and plants the same roles are performed by lytic vacuoles

Vacuole

Storage organelles
Bigger in plant cells as they also mantain structure
Filled with water containing inorganic and organic molecules

Nucleus

Cellular control centre in eukaryotes.
Contains the genetic information (DNA and RNA) surrounded by a two-layer nuclear envelope
Found at the centre of the cell.
For communicating with other organelles

Nucleolus

Where ribosomes are assembled, DNA is kept and RNA is transcribed.
RNA, nucelous messages and proteins are transported out of the nucleus through the nuclear pores.

Ribosomes

floating freely and function in the cytoplasm or bound to RER
small, made up of 50 proteins and several long RNAs bound together.
for protein synthesis (RNA is translated into protein
many in the cell
non-membrane bound

Cytoplasm

A jellylike fluid inside the cell which provides a platform for other organelles to operate
All of the functions for expansion, growth and replication are carried out in the cytoplasm

Chloroplast

Only in plant cells
Convert light energy to chemical energy (photosynthesis)
pigment from chlorophyll.
outer membrane and inner membrane separated by an intermembrane space.
interconnected system0 of stacks of disks (thylakoid)
Has own DNA (Plasmid

Centrioles

Paired cylindrical organelles near nucleus
Made of nine tubes, each with three tubules
Involved in cellular division
Lie at right angles to each other and not found in plant cells

Cytoskeleton

Made of microtubules
Supports cell and provides shape
Helps move materials in and out of cells

cell membrane

Separates the interior of the cell from the outside environment.
Consists of a semipermeable lipid bilayer
Regulates the transport of materials entering and exiting the cell

Mitochondria

Many in the cell
smooth outer membrane and folded inner membrane separated by an intermembrane space.
For converting sugar into ATP energy (cellular respiration)
Increases surface area for reactions
Has own DNA (plasmid)

cell respiration

the process in cells in which oxygen is used to release stored energy by breaking down sugar molecules

plant vs animal cells

1. Plant cell has cell wall, animal cell does not.
2. Plant cell has one large vacuole, animal cell has several small vacuoles.
3. Plant cell has choloroplasts for making food, animal cell does not.

unicelluar organism can...

carry out all functions of life in one cell

Magnification, Image and Actual Size

m = i/a
a = i/m
i = ma

FOV

Feild number / objective magnification

total magnification

objective lens m x ocular lens m

object size

FOV/objects across

mm to micrometers

mm to micrometer = x 1000
Micrometer to mm = /1000

Characteristics of living things

Movement
Respiration
Sensitivity
Growth
Reproduction
Excretion
Nutrition

Are viruses living?

no, as they can't keep stable, grow or make their own energy, but they can replicte, and adapt to their enviroment

Light vs TEM vs SEM

Light = x2000 magnification
TEM = beam of electrons through an object, cross sectional 2d image, x2million magnification up to a subatomic level, very clear image
SEM = 3d image of shape and surface texture, beam of electrons, 10 to 500000 x maginification, as small as atom

light vs. electron microscope

light - uses light, glass lens, 0.25um - 0.3um resolve, x2000 m, 5um or thicker specimen, coloured, senn through lens, specimens may be living or dead, internal structure

electron - uses electron beam, dired or dead specimen, electromagnetic lens, 0.001 um resolve, 100000 to 300000x m, 0.1um or thinner specimen, not coloured, seen throgh tech, external structures

Prokaryote

first form of life
double stranded DNA bundled together in nucleiod area
non-membrane bound organelles
unicellular
0.1-5 um
bacteria and archea groups

Prokaryote vs. Eukaryote

1. prokaryotes do not have nucleus (DNA bundled in nucleiod area)
2. prokaryotes have double starnded and circular DNA
3. prokaryotes have no membrane-bound organelles
4. Both have cell membrane, ctyoplam, ribosomes and sometimes cell wall
e. pro = coupled, meaning translation begins during mRNA synthesis, eu = not coupled, so transcription occurs in the nucleus, producing mRNA, which exits the nucleus, and translation occurs in cytoplasm
f. Prokaryotes are only unicellular
g. pro = 0.1-5 μm, eu = 10-100 μm

Flagella

whiplike tails found in prokaryotes to aid in movement

Pilli/fimbrae

protein structures that extend from the bacterial cell envelope, up to 2 μm, to attach the cells to surfaces

Plasmid DNA

small, circular, double-stranded DNA molecule that is distinct from a cell's chromosomal DNA

Capsule

A sticky layer that surrounds the cell walls of some bacteria, to protect the cell surface and help glue the cell to surfaces.

Nucleiod

Region of prokaryotic cells where DNA is located

Septum

key cellular structure during binary fission that is formed between the nucleoids and the center of the cell

Theory of Endosymbiosis

Eukaryotic cells emerged when mitochondria and chloroplasts, once free-living prokaryotes, took up permanent residence inside other larger cells.

Binary fusion

Asexual reproduction for prokaryotic cells
1. Replication -> replication into 2 idnetical DNA molecules
2. Condensation of DNA -> two identical cicrular chromosomes
3. Attachment -> each chromosome attaches the inside the cell membrane using anchors
4. Elongation ->size increase length-ways
5. Seperation -> chromosomes move to the opposite ends of the cell
6. Formation -> new cell wall and membrane forms and divides into 2 identical daughter cells

diffusion

Movement of molecules from higher concentration to lower concentration.

which way to solutes diffuse

higher concentration to lower concentration.

Osmosis

Diffusion of water through a selectively permeable membrane from higher concentration to lower concentration.

is diffusion passive or active

passive as it requires no energy as moelcules move naturally due to the membrane

if a beaker has a water permiable membrane with one side of salt+water (A) and on side of water (B), which way will diffusion occur?

from B to A, so water rises on A and falls on B as salt+water can't move through the membrane

if a beaker has a membrance with 8 salts (A) on one side and 0 (B) on the other, which way will diffusion occur?

A to B as the salts move across to balance and create a equilbrium

Active transport requires...

energy

role of lipids

energy reserve, regulate hormones, transmit nerve impulses, cushion vital organs, and transport fat-soluble nutrients

sa:v ratio meaning

as size increase sa:v ratio decreases, high sa:v ratio means cells can reatin more

membrane permability

all molecules can diffuse across the membranse

semi-permability

some molecules can diffuse across the membrane but others cannot

solute

substance that dissolves in a solvent

soloution

homogeneous mixture of one or more solutes dissolved in a solvent

concentration gradient

the change of concentration per unit distance in a solution caused by diffusion between two regions where the concentration of a substance differs

hydrophollic

attracted to water

hydrophobic

reples water

cell cycle

Interphase: G1, G2, Syntheis
Mitosis
different cells take differnet amoutn of time to comeplete

G1

recovery from previous divison
cell doubles its organelles
accumlates raw materials for DNA syntheis
becomes larger

Syntheis

DNA replication
chromosones enter with 1 chormatid each and leave with 2 identical chromatids each
centromere duplicates

G2

cell synthesis proteins need for divsion

Mitosis

duaghter chromosomes distributed in two daughter cells, 10% of cell cycle
prohase, premetaphase, metaphase, anaphase, telophase, cytokensis

prophase

chromosomes bceome visible and fully condense
nucelar membrane disapperas and completly breaks down
spindle forms

metaphase

paired chromatids line up at cell equator

anaphase

centromere splits
spindle fibres pull chromatids to ploar ends of the cell

telophase

nucelar membrane reforms around each DNA set
spindle disapperas

cytokensis

cytoplasm divides to form 2 identicial daughter cells cleavage forrow forms
chromosomes begin to decondense and return to stringy form
cell plate forms
cells seperated by a new wall

spindle fibres

aggregates of microtubles that move chromatids to ploar cells ends during mitosis

chromatin

composed of DNA and histones packaged into thin stringy fibres
condenses to form chromosomes during mitosis

chromatid

either of the two starnd of a replicated chromosoe
are sister chromatids when connected by centromere
sister chromatids seperate to become duaghter chromosomes in duaghter cells at end of mitosis

centromere

reigon on chromosome that connects two sister chromatids

microtubles

fibrous, hollow rods that support and shape cell

eukaryotic chromosomal organistaion

chromosome, supercoil, coiling, chromatin fiber, nucleosome

somatic cells

all body cells except reproductive cells
each contains 46 chromosones (2 sets of 23, one set from each parent)
diploid

reproductive cells

gametes
one set of 23 chromosomes, haploid

chromosomes

long, thin, stringy, single-starnded fibre combination of condensed DNA
connected in cental region called centromere
each strand is chromatid
duplicated are double-stranded (like in mitosis), X shaped, identical

chromosomes of the same type are...

homologous as they have genes controlling same traits in same position (same lengths, centromere locatopm, similar pattern when starined)

paternal homology

chromosome set from father

maternal homology

chromosome set from mother

DNA

deoxyribonucleic acid
double-stranded helix strcuture
controls type of cell, what chemical changes occur for function, function and type of organism
every cell has same amount

DNA molecule

very large
made of nucelotides (long chain of subunits)
three components:
1. pentose sugar (deoxyribose)
2. phosphate group (-PO4)
3. nitrogenous base

DNA types

two types of DNA: DNA and RNA
DNA is more stable double-stranded form that stores genetic blueprint
RNA is more versatile single stranded form that transfers genetic info

Bases

base pairs made of two strands of nucelotides joined by hydrogen bonds
purine: adenine, cytosine
pyramidine: thymine, guanine (uracil in RNA)
a+t = 2 hydrogen bonds
c+g = 3 hydrogen bonds
hydrogen bonds are weak but their are millions in DNA

DNA strcuture

sugar-phosphate backbone and base pairs

chagraff's rule

1:1 ratio between pryamidine and pruine so always adenie and thymine, cytosine and guanine

polymer nuceleotide/monomers

one DNA strand is a polymer of nucelotides with millions of them
sugar-phosphate chains on outside and starnds are held together by covalent chemical bonds between bases

Stable arrangement

strands run in opposite direction for base pairing
two strands are antiparallel
as antiparallel chains lenghten, atoms orgainse themselves into stable double-helix structure

DNA function

codes for protiens and enzymes by producing enzymes

gene

DNA sequnece

amino acids

20 kinds with unique shapes that attach to each other to create proteins
need perfect shape to function
DNA tells amino acids how to line up to make protiens
found in cytoplasm

organisation of organisms

organisim -> organs -> tissue -> living cells -> proteins -> amino acids

how are proteins made

RNA exits nucelus through pores and enters ribosome to build protiens
ribosome reads RNA code 3 letters at a time to create a chain of amino acids that bend prefectly to make proteins
every 3 letter of RNA code corresponds to an amino acid

photosynthesis

makes glucose in plants (similar to cellular respiration)
plants make glucose by capturing light through pigment chlorophyll
two reactions make up photosynethis: light dependent and light independent

chemical equation of photosynethsis

6CO2+6H20 -> (light) C6H12O6+6O2

inputs and products of photosynethis and worded equation

carbon dioxide +water -> (light) glucose +oxygen
inputs: carbon dioxide and water
products: glucose and oxygen

chlorophyll

absorbs red and blue light and reflects green, so most plants appear green
found in chlorplast

light dependent reaction/LDR

occurs in thylakoids
light captured is 'split'
produces water, oxygen, ATP and NADPH

light independent reaction/calvin cycle/dark reaction/LIR

occurs in stroma
carbon dioxide enters through pores called stomata often at the bottom of the leaf
it is 'fixed' by another enzyme to create a more usauble orgainc form
ATP from LDR in energy in LIR
NADPH from LDR supplies reducing power by adding high energy electrons to the process
fixed carbon dioxide, ATP and NADPH used to make a product that can be converted into glucose (sugar)

thylakoids

small compartment in chlorphyll that has pigment
stack of thylakoids = granum
multiple stacks = grana

stroma

fluid outside thylakoids

CAM photosynethsis

Crassulacean Acis Metabolism
in desert plants to prevent dehydration
opens stomata at night when cooler to capture carbon dioxide and chemically store it to use the next day when its hot but have stomata closed