biology term 1 2023

Cells

building blocks of life

Differentiation

process in which cells become specialized in structure and function

expressed gene in differentiation

switched on

unexpressed gene in differentiation

switched off

organelles

structures found inside cells that perform a specific function

prokaryotic cells

simple cells that lack a cell nucleus and membrane-bound organelles

Prokaryotes

single-celled organisms that don't contain a nucleus or any membrane-bound cell organelles

prokaryote example

Bacteria and Archaea

cytoplasm

gel-like substance enclosed within the cell found where cellular chemical reaction take place

Nucleoid

A dense region of DNA in a prokaryotic cell

Ribosmes

plasma membrane

surrounds the cell and separates the contents of the cell from its surroundings

unicellular organism

An organism made up of one cel in which the single cell is responsible for carrying out all functions of life that are nesscary for its survival

Unicellular example

bacteria, amoeba, chlorella, paramecium, euglena

Metabolism

All of the chemical reactions that occur within the cell

Multicellular

Made up of more than one cell, differentiate to make differentiate to make different tissues that pefrom specialised functions

multicellular example

plants and animals

plasmid

A small ring of DNA that helps bacteria to adapt to unusual situations such as antibiotic resistance

Pili

hair-like structures found on surface which helps bacteria adhere to each other for the transfer of DNA from one cell to another by process called conjugation

Flagella

whip-like structure that helps bacteria move around

cell wall

A rigid layer of nonliving material that maintains cell shape + prevents it from bursting, made of peptidoglycan

Ribosomes

protein synthesis

prokaryotic ribosomes

70s

S (Ribosome units)

how fast molecule will sediment centrifuged

ATP (adenosine triphosphate)

high energy molecule which is composed of adenosine and three phosphate groups

ATP function

transfer and storage of energy for chemical reactions that take place in the cell

Nucleolus

ribosome synthesis

Synthesis

combining parts into a whole

Nucleus

surrounded by a phosphorus double membrane

Nucleus function

Contains DNA (genetic information that controls the cell)

mitochondrion

contains own ribosomes + DNA, made of two membranes (outer and inner which is folded inwards to increase surface area)

Mitochondrion function

is cellular respiration, facilitating the production of ATP

aerobic respiration

requires oxygen

Lysosomes

contains many enzymes

Lysosomes function

Digestion and recycling dead organelles + foreign particales

Rough Endoplasmic Reticulum

network of tables that extend from the nucleus to the rest of the cell

Rough Endoplasmic Reticulum function

protein synthesis and transport

Smooth Endoplasmic Reticulum

no ribosomes of the surface

Smooth Endoplasmic Reticulum function

Synthesises and processes lipids

Golgi apparatus (eukaryotic animal cell)

many flattened sacs stacked one top of each other, has two sides (cis (receives products from endoplasmic reticulum), trans side (vesicles are released))

Golgi apparatus function (eukaryotic animal cell)

processes proteins received through RER (packaging + modifying proteins to be used either inside the cell or excreted outside the cell)

Magnification

the ratio of an object's image size to its real size

Resolution

clarity of the view or image

Vacuoles

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

chloroplasts

surrounded by two membranes; contains own ribosomes + DNA+ captures energy from sunlight and use it to produce food for the cell

Hydrophobic

repelled by water (non-polar)

Hydrophilic

attracted to water (polar)

phospholipid bilayer

a two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward

intergral proteins

membrane proteins that penetrate the phospholipid bilayer

peripheral proteins

membrane proteins that remain on surface

stem cells

undifferentiated cells that can divide and differentiate into different types of cells

hematopoietic stem cells

produce blood cells in bone marrow

embryonic stem cells (for)

easy to obtain

pluripotent

unlimited growth potential

less chance of malignant tumours developing

less chance of genetic damage due to mutations with adult stem cells

embryonic stem cells (against)

destruction of embryo

possible tumor development

likely to be genetically different

adult stem cells (for)

no destruction of embryo

low tumour development chance

no chance of rejection (compatible with adult tissues)

no kill

adult stem cells (against)

limited differentation

not obtained easily sometimes

less growth potential

cord blood stem cells (for)

easily obtained

pluripotent

no embryo destruction

tumor development chances are low

no rejection

differentiation able

cord blood stem cells (against)

has to be obtained immediately after birth

limited quantities where

dilute solution

a solution that contains a small amount of solute dissolved in solvent

concentrated solution

a solution containing a large amount of solute dissolved in solvent

aqueous solution

a solution in which water is the solvent

soloution

a homogeneous mixture of two or more substances (the solutes) dissolved in another substance (the solvent)

simple diffusion

movement of a solute from an area of high concentration to an area of low concentration

Osmosis

Diffusion of water through a selectively permeable membrane, from hypotonic to hypertonic

hypotonic

Having a lower concentration of solute

hypertonic

Having a higher concentration of solute

isotonic solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution

turgid

swollen as from a fluid; bloated

flaccid

to limp

plasmolysed

the condition of a plant cell that has lost so much water that its cytoplasm shrinks and pulls the cell membrane away from the cell wall

active transport

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy

facillitated diffusion

process that moves materials from high to low concentration with the help of protein channels; does not require energy

Exocytosis

Large molecules going OUT of the cell (energy required)

Endocytosis

Large molecules going INTO the cell

Phagocytosis

Cell eating

endosymbiotic theory

evolutionary theory which describes the endosymbiotic relationship between organisms and how its resulted in the evolution of eukaryotic cells sand prokaryotic cells

cell cycle

series of events that cells go through as they grow and divide

Cytokinesis

division of the cytoplasm

1. Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

2. Mitosis

division of nucleus to form two genetically identical daughter nuclei

Prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Metaphase

Chromosomes line up in the middle of the cell

Anaphase

chromosomes separate and move to opposite ends of the cell

Telephase

the chromosomes become longer, thinner, and less distinct. the nucleur membrane forms. the neocleolus reappears and cell division is nearly complete

DNA replication

the process of making a copy of DNA

sister chomatids

identical chromatids joined at a centromere

benign tumor

a mass of abnormal cells that remains at the site of origin

maligant tumor

cancerous tumour that is invasive enough to impair the functions of one of more organs

binary fission

A form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

metstasis

the spread of cancerous cells to locations distant from their original site

Mutations

a random error in gene replication that leads to a change

Which process involves mitosis?

plant cell due to cell plate formation

Mutation causes

spontaneous generation, radiations, and certain chemicals

carcinogens

Cancer causing agents

Germline mutations are

inherited

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

Giant Algae challenges theory (3)

complex organism

large in size

single nucleus

giant algae

atypically large / uni-nucleated cells

aseptate fungal hyphae

Challenges the idea that a cell is a single unit

Functions of Life (MR. H. GREN)

, Metabolism

Response

Homeostasis

Growth

Excretion

Nutrition