Stage 2 - Cells

What is a cell?

Smallest independent unit of life

Part 1 of cell theory

All living things are mades up of one or more cells

Part 2 of cell theory

Cells are the basic unit of structure and function in all living things

Part 3 of cell theory

Every cell arises from a pre-existing cell

What are some features of a prokaryotic cell?

NO membrane-bound organelles, NO nucleus, DNA is one singular circular chromosome

What are some features of a eukaryotic cell?

CONTAINS membrane-bound organelles, has nucleus that contains multiple linear chromosomes

Where else can DNA be found in eukaryotic cells

Mitochondria and Chloroplasts (plant only)

Where else can DNA be found in prokaryotic cells

Plasmids

What is eukaryotic cells found in

plants, animals, fungi and protists

What is an organelle

Specialised subunit of a cell that has special function

What is the function of the nucleus

Stores genetic material

What is a nucleolus

A region inside the nucleus composed of DNA, RNA, and proteins

What is the function of the nucleolus

Site of ribosomal RNA synthesis ad ribosome production

What is the function of the mitochondrion

Site of final stages of aerobic respiration

Describe the structure of the mitochondria

Contains double membrane - highly folded inner membrane as well as outer membrane, has own circular DNA and ribosomes

What does being a semi-autonomous organelle mean?

Capable of independent reproduction within the cell

What is the worded equation for aerobic respiration

Glucose + Oxygen --> Carbon Dioxide + Water

What is the function of chloroplast

The site of photosynthesis

What is photosynthesis

Where light energy is converted into chemical energy and stored in the bonds of glucose

Describe the structure of the chloroplast

Contains chlorophyll which gives the green pigment, contains inner and outer membrane

Name the two semi-autonomous organelles

Chloroplast and mitochondria

Write the worded equation for photosynthesis

Carbon Dioxide + Water --Light--Chlorophyll--> Glucose + Oxygen

What are the two main types of the endoplasmic reticulum

Rough endoplasmic reticulum, Smooth endoplasmic reticulum

What is the function of the Rough ER

Site of protein synthesis, site of membrane synthesis

What is the function of the Smooth ER

Involved in the detoxification of drugs, poisons, and alcohol, synthesis of lipids

What is the main structural difference between the Smooth and Rough ER?

Rough ER has ribosomes attached and Smooth ER doesn't

What is the function of the Golgi body/apparatus

Modify, sort, and package macromolecules into membrane-bound vesicles to be secreted from the cell

What is a vacuole

Fluid-filled space surrounded by a membrane

What are the two main functions of a vacuole

Storage: Excess water, slats, sugars, amino acids

Shape retention: Maintaining water balance/salt equilibrium

Describe the structure of a lysosome

Membrane enclosed organelles containing digestive enzymes that break down substances

What is the function of the lysosome

Digest food vacuoles, destroy harmful bacteria, recycle damaged organelles or macromolceules

What is the function of the ribosome

Site of protein synthesis

What is the cytoskeleton

Structure made of proteins that form long fibres and provide a scaffold/framework in the cell

Name at least two functions of the cytoskeleton

Chromosome alignment and movement in cell division: Microtubules form spindle fibres that align/seperate sister chromatids

Intracellular transport of organelles and vesicles: Microtubules act as train tracks to transport organelles or vesicles within cell

Cell motility (movement): microtubule in cilia or flagella enable cells to move

Maintenance of cell shape: Protein structures help maintain the cells shape

What is the function of the cell wall

Maintain cell shape

What is the cytoplasm and cytosol

CYTOSOL is the intracellular liquid inside the CYTOPLASM

What is the cell membrane

A barrier separating the interior of a cell from the exterior environment

Describe the structure of the cell membrane

Composed of a bi-layer of phospholipids

Describe the structure of the phospholipids that make up the bi-layer

Phosphate-containing head that is hydrophilic and two tails that are hydrophobic

What are three features of the fluid-mosaic model

Proteins and other macromolecules embedded (1) in phospholipid bi-layer (2), The membrane is dynamic (constantly in motion) (3)

What is the main function of the mosaic model

to maintain a stable intracellular environment by controlling passage of substances in and out of the cell

What is an aquaporin

Kind of channel protein that allows the transfer of water across the membrane

true or false: smaller cells have a larger surface area:volume ratio which makes them less efficient in moving substances across their membrane

false

The difference between an autotroph and a heterotroph

Autotroph's produce their own glucose whereas heterotrophs get their glucose from external substances (like food)

What is oxygen a reactant for In both hetero/autotrophs

Aerobic respiration

What processes make CO2

Autotroph: aerobic respiration and fermentation

Heterotroph: aerobic respiration

Are there different outputs of fermentation depending on the kind of cell? If there is, name them

Heterotrophs: Lactic acid (animals), ethanol (yeasts)

Autotrophs: Ethanol (plants)

What does the cell membrane being semi-permeable entail?

allows some substances to pass and not others

What is diffusion

High -> low concentration gradient, passive transport, net movement of molecules

name the two kinds of diffusion

Simple and facilitated

What is simple diffusion

small molecules pass freely across the membrane

what is facilitated diffusion

diffusion of molecules via transport proteins in the membrane

What are the kinds of transport proteins that help with facilitated diffusion

Carrier and channel proteins

What is a channel protein and what does it let through

Passageway that allows water and ions through the membrane

What does a carrier protein carry and how does it do so

Carries larger molecules like amino acids and glucose and does so by binding to the molecules and undergoes conformational change, allowing molecules passage

What is water diffusion called and how does water move?

Osmosis - water moves from a low solute (high water concentration) to a high solute (low water concentration)

What does hypOtonic mean

High water concentration (low solute)

What does hypERtonic mean

Low water concentration (high solute)

Why don't plant cells burst when in a hypotonic solution

the cell wall

What is active transport and what does it need

Low -> high concentration gradient and needs ATP/energy to occur

What kind of protein is used for active transportation

Protein pump

Step 1 of exocytosis

large molecules (protein/hormone) packaged into vesicle at Golgi body

Step 2 of exocytosis

Vesicle moves towards cell membrane

Step 3 of exocytosis

Vesicle fuses with cell membrane and expels content into extracellular environment

Step 1 of endocytosis

Membrane begins to invaginate near particle

Step 2 of endocytosis

Membrane surrounds particle completely

Step 3 of endocytosis

Membrane surrounded particles pinch off to form intracellular vesicle

What do cells use the sun for

Light energy (photosynthesis) and Heat energy (ensure suitable temperature)

Name three limiting factors of photosynthesis

Temperature, carbon dioxide concentration, water availability, wavelength/colour of light, light intensity

Fill the blanks:

The total energy … when new chemical bonds are forming is … than the energy required for the …

released, greater, initial break

What is a form of anaerobic respiration

Fermentation

Anaerobic respiration is less efficient than aerobic respiration. Why?

Aerobic respiration: glucose almost completely broken down and producing 36-38ATp

Anaerobic respiration: glucose partially broke down and producing2 ATP

What is the worded equation for alcohol fermentation

glucose -> ethanol + carbon dioxide

what is the worded equation for lactic acid fermentation

glucose -> lactic acid (split glucose molecule in half)

What does ATP stand for

Adenosine TriPhosphate

What is ATP

cells immediate cells immediate source of energy that is used for most energy requiring processes

What is the worded equation between ATP and ADP

ADP + Pi

What does Pi stand for

inorganic phosphate

How is the ADP combined with the Pi

Energy used to breakdown glucose is used to combine the two

what are the three components of ATP and ADP

Phosphate groups, Ribose sugar, Adenine

Why do metabolic pathways often consist of small, regulated steps that occur in a series?

Allows for greater control and efficiency of energy release, and to avoid negative cellular conditions

Why are metabolic pathways not 100% efficient

Some energy trapped but some is also lost as heat

What are intermediate compounds

molecules formed in metabolic pathways or enzyme catalysed chemical reactions

What do intermediate compounds do

play a vital role in regulating metabolic processes and energy production within cells

What is binary fission?

bacteria divides in half

Who performs binary fission

Prokaryotic cells

Step 1 of binary fission

DNA replicates to form 2 identical DNA molecules in cytosol

Step 2 of binary fission

Chromosomes gradually seperate, cell wall and plasma membrane grow inward to constrict the cell and divide into 2

Who performs mitosis

Eukaryotic cells

What does mitosis do

Repairs and replaces damaged somatic cells

What are the three phases of interphase

G1, S phase, G2

In what interphase stage does cell division stop

G1