A2.2 CELLS

main component of cytoplasm

water

cell theory

cells are the basic & smallest unit of life, they can only come from other cells

3 basic components of cells

plasma membrane, DNA, cytoplasm

prokaryotic cells

cells without a nucleus or other membrane-bound organelles (simpler)

eukaryotic cells

cells that contain membrane-bound organelles, including a central nucleus (more complex)

cytosol

liquid part of cytoplasm

chitin

building material for fungi cell wall

prokaryotic cells have ... ribosomes

70s

eukaryotic cells have ... ribosomes

80s

prokaryotic cells have ... DNA

circular

eukaryotic cells have ... DNA

linear

DNA is contained in ... in prokaryotic cells

nucleoid

DNA is contained in ... in eukaryotic cells

nucleus

prokaryotic cells have ... based cell wall

peptidoglycan

eukaryotic cells have ... based cell wall

cellulose

prokaryotic cells: ATP production occurs in...

infolded regions of cell surface membrane

eukaryotic cells: ATP production occurs in...

mitochondria

what do prokaryotic cells have on the outer surface

pili, flagella

what's it called when the plasma membrane bursts

lysis

cause of lysis

excess pressure or viruses

lysis always leads to...

the death of a cell

role of plasma membrane

controls entry and exit of substances

what do genes contain?

information needed for a cell to carry out all its functions (eg. making proteins)

proteins are needed for...

growth and repair / enzymes

first organisms to evolve on earth

prokaryotic cells

prokaryotic cells have a ... DNA

naked

what does a naked DNA mean?

not associated with histone proteins

eukaryotic cells have ... cytoplasm

compartmentalized

mitochondrion is surrounded by a...

double membrane

role of mitochondria

carry out aerobic cell respiration

characteristics of life (7)

Metabolism

Response to stimuli

Homeostasis

Growth

Reproduction

Excretion

Nutrition

why do unicellular organisms have a limit on size?

surface area to volume ratios

(cell cannot survive if he surface area is too small relative to the cell size - it is important to have higher SA to vol ratio for survival)

benefits of SA/V ratio

faster absorption of food, faster rate of heat loss, faster rate of material exchange

resolution vs magnification

resolution is the amount of detail, magnification is the amount of enlargement

smaller wavelengths can penetrate ______

more

example of smaller wavelength

x-rays

advantages of cell compartmentalization in eukaryotes

efficiency of metabolism, localized conditions (eg. pH), toxic/damaging substances can be isolated, number and location of organelles can be changed depending on the cell's requirements

examples of atypical cell structure in eukaryotes

red blood cells, phloem sieve tubes - no nucleus

skeletal muscle, Aseptate fungal hyphae - multinucleate

resolution is limited by...

wavelength of radiation

types of microscopes

light, transmission electron, and scanning electron

compare resolution of light and electron microscopes

electron > light (electron has shorter wavelength)

compare price of light and electron microscopes

electron > light

compare organism preservation of light and electron microscopes

electron microscopes lead to death of organism, whilst light microscopes preserve them

freeze-fracture technique in electron microscopes

physically breaks apart a frozen biological sample, used to produce images of surfaces within cells

compare colors of light and electron microscopes

light microscopes show color, but electron microscopes do not (black and white)

fluorescent microscopy

uses higher intensity light to illuminate the sample, longer light wavelength is emitted

cryogenic microscopy

molecular, 3D level

magnification formula

magnification = image size / real size

1000 nm = ___ um

1 um

1000 um = ___ mm

1

which cells have plastids?

plants only

which cells have a cell wall?

plant and fungal cells only

which cells have vacuoles and vesicles?

animal, plant, fungal cells

which cells have centrioles?

animals only

which cells have cilia and flagella for movement?

animals only

the genetic code is

universal

all cell arised from

LUCA (Last Universal Common Ancestor)

symbiosis

close interaction of two species where at least one species benefits from the interaction, neither is killed

endosymbiosis

symbiotic relationship where one organism lives inside the other

emergence of eukaryotic cells

1. development of the nucleus

2. development of mitochondria

3. development of chloroplast

the smaller prokaryotic cell is supplied with...

nutrients and food

the larger cell is benefited with...

receiving energy from aerobic cell respiration or sugars from photosynthetic bacteria

endosymbiotic theory

eukaryotic cells evolved from prokaryotic cells

proof of endosymbiotic theory

similarity between mitochondria and chloroplasts & prokaryotes

features of mitochondria and chloroplasts that are similar to those of prokaryotes

circular DNA independent from rest of cell, 70s ribosomes, divide by binary fission, double membranes, similar size

development of specialized cells happens during...

embryonal stage

multicellular organisms evolved from...

unicellular eukaryotes

advantages of multicellularity

cell specialization, larger body size

all diploid cells of an individual share ______ genome

the same

every cell contains _______ of genetic instructions for that organism, but _______ are expressed

the entire set, not all genes

_____ genes are active in embryonic stem cells

all

newly formed cells receive signals which ______ genes

deactivate

layers of embryos (of humans) from outer to inner

ectoderm, mesoderm, endoderm

ectoderm

skin, nails, teeth / nervous system, eyes, lining of mouth

mesoderm

blood & lymph, bone & notochord (vertebra), muscle / excretory & reproductive systems

endoderm

digestive system / lining of respiratory, excretory & reproductive systems

first organisms to appear on earth

prokaryotes

prokaryotes divide by

binary fission (asexual reproduction)

do prokaryotes have organelles?

no but exception of ribosomes

what are chromatins?

loosely coiled DNA and proteins, material from which chromosomes are made)

what are chromosomes?

entire chromatin tightly bound

organelles examples

nucleus, mitochondria, golgi, ER, lysosomes, vacuoles, mitochondria, chloroplast, ribosomes, microtubules

rough endoplasmic reticulum function

synthesizes proteins which are then transported by vesicles to the golgi apparatus for modification before secretion outside cell

structural difference between rER and sER

rER has eukaryotic ribosomes embedded in the membrane, while sER does not, giving it a smooth appearance

smooth endoplasmic reticulum function

metabolize lipids, steroid hormones, store calcium ions

ribosomes function

create proteins by translating mRNA

where are ribosomes created?

nucleolus

two types of ribosomes

free ribosomes and bound ribosomes

difference between two types of ribosomes

free ribosomes create proteins to be used by the cell, bound ribosomes (like those on rER) create proteins to be secreted outside of cell

what is golgi apparatus made of?

flattened membrane sacs called cisternae

golgi apparatus function

finalize protein modification

what are vesicles/vacuoles?

sacs made up of membrane containing fluid

plant cells have ______ vacuoles

permanent, large

animal cells have _______ vacuoles

temporary, small

what are lysosomes?

spherical vesicles w/ single membrane containing digestive enzymes

where are lysosomes formed?

golgi

lysosomes function

digesting and breaking down material

lysosomes have a _________ internal environment

acidic

mitochondria function

create ATP through cell respiration

mitochondria structure

outer and inner membrane, intermembrane space, mitochondrial matrix, cristae