biology december exam 2024

what do all living organisms contain

cells

what are the two main types of cells

prokaryotic and eukaryotic

what are considered are prokaryotic cells

bacteria and archaea

what are considered as eukaryotic cells

plants, animals, fungi and protists

what do eukaryotes contain

cell membrane

cytoplasm

nucleus that contains DNA

membrane bound organelles

what do prokaryotic cells contain

cell membrance

cytoplasm

no nucleus- DNA is free in the cytoplasm

what are unicellular organisms

one celled organisms that carry out all the functions of life

protists are…

uncellular but eukaryotic

bacteria is…

unicellular and prokaryotic

cell wall

protection from chemical and mechanical damage

maintains shape

prevents cell from bursting bc of too much water

plasma membrane

partially permeable

controls what enters and leaves the cell

cytoplasm

jelly-like substance where all the metabolic reactions occur

capsule

gives extra protection of the cell (not all cells have it)

flagellum

whip-like structure used for movement

ribosomes

where proteins are made

plasmid

additional DNA with several genes

DNA

genetic material

nucleoid region

carries genetic material, controls all processes for the cell

are plants and animals cells prokaryotic or eukaryotic

eukaryotic

what are the two types of microscopes

light and electron

what are the characteristics of a light microscope

light is used as a source of radiation

color images possible

portable

living organisms observed

what are the characteristics of electron microscopes

uses beam of electrons as a source of radiation

living organisms cannot be observed

black/white images available

not portable

what is magnification

the ability to enlarge an image

what is resolution

the ability to define two close objects as seperate

structure of plasma membrane

made of phospholipids and protiens

partially permeable

holds the cell together

controls what enters and leaves the cell

structure of cytoplasm

contains water with different solutes dissolved in it

supports the cell organelles within

where all biochemical reactions occur

structure of mitochondria

where are respiration happens (produces energy)

ATP is needed to drive evergy consuming processes

many more mitochondria in “active cells” like liver cells and pancreatic cells

structure of the nucleus

surrounded by nuclear envelope with pores

contains thread like chromosomes made of DNA

controls all cell processes

structure of ribosomes

small structures where proteins are made during protein synthesis

structure of the endoplasmic reticulum

system of channels and membranes in the cytoplasm usually connected to the nuclear envelope

structure of the rough endoplasmic reticulum

ribosomes attached

proteins made are usually exported out of the cell

travels and gets modified though ER towards cell membrane

structure of smooth endoplasmic reticulum

no ribosomes attached

makes phospholipids, lipids and hormones

function of golgi apparatus

system of sacs close to the plasma membrane

proteins from the ER are further modified and packaged into vesicles before being secreted from the cell

stucture of vesicles

small sac like structures in cytoplasm surrounded by a membrane to prevent the substances inside from interfering with the cell

contain many different substances

structure of lysosomes

membrance bound organeeles

contain digestive enzymes that break down damaged organelles

rarely found in plants

structures of the centrioles

structures involved in cell division

structure of cilia/flagellum

not all cells have them

used for movement

structure of cell wall (plant cells only)

surrounds cell, gives it shape

made of tough cellulose

protects from chemical and mechanical damage

prevents cell from bursting

structure of choroplasts (in plant cells only)

cite of photosynthesis

contains green pigment, chlorophyll

structure of the large vacuole (in plant cells only)

takes up most of the cell

liquid inside is called cell sap

stores water and other substances

what are the levels of organisation in the body

atoms, molecules, cells, tissues, organs, organ systems, organism

what is the first statement about cell theory

all living organisms are made out of cells

what is the second statement about cell theory

all cells come from pre existing cells

what is the third statement about cell theory

the cell is the smallest living unit in all organisms

what does differentiation result in

specialization

what happens during differentiation

some cell genes are “switched on” while other genes are “switched off” meaning cells will develop differently

what is the function of the ciliated epethelial cells

help trap bacterial and dust particles that have entered the respiratory tract

the flicking movement moves the bad mucus upward so it is swallowed and away from the lungs

what are ciliated epethelial cells specialised for

keeping the lungs clean

what can reduce effectiveness of ciliated epethelial cells

smoking

what are paliside leaf cells

plant cells

located on the tops of leaves

what are paliside leaf cells specialised for

photosynthesis

what are root hair cells

plant cells

water and dissolved mineral ions are absorbed form the soil into the roots by the cells

what are root hair cells specialised for

absorption on the surface of the root

what are xylem vessels

plant cells

used to transport water with dissolved minteral ions to leaves

how do xylem vessels differentiate from xylem cells

by losing their cytoplasm and cross wall and impregnating the walls with a very tough, waterproof substance called ligning

what are nerve cells (neurons) specialised for

conducting a nerve impulse around the body

what are nerve cells (neurons)

made of a cell body with nucleus

impulses travel along the long axons and through to another cell

what are red blood cells

made in the bone marrow from stem cells and then differentiate

what are red blood ceels specialised for

transporting oxygen from the lungs around the body

what are the characteristics of red blood cells

no nucleus

disc-shaped

large surface area

smooth surface

what are the gametes (human sex cells) specialised for

reproduction

what are stem cells

undifferentiated cells

what are stem cells important for

the grown the replacing damaged cells

what are early embryonic cells

stem cells that will differentiate along any pathway and become any type of cell

what are stem cells able to possible treat

parkinsons disease

type 1 diabetes

paralysis

what are the advantages of using stem cells

easy to extract from embryo

produce any type of cell

replace faulty cell with healthy cell

if taken from person to be treated, the body will not reject

what are the disadvatages of using stem cells

may produce cancer cells rather then healthy cell

adult stem cells can only produce a few type of cells

destroys the embryo

magnification=

size of image/ actual size of object

how do you calculate magnification from images with a scale bar

magnification= measured length of scale bar (ruler)/ acutal length of scale bar

what are the seven characteristics of life

metabolism

respone

homeostasis

growth

reproduction

excretion

nutrition

what is metabolism

biochemical reactions in the cytoplasm

what is response

the ability to move/ react to environment

what is homeostasis

the ability of the body to maintain a state of equilibrium

what is growth

irreversible increase in size

what is reproduction

where individuals are generated- sexual and asexual

what is excretion

expelling waste products out of the cell

what is nutrition

obtaining food to provide energy and materials needed for growth

are viruses alive

no because they are not able to carry out any of the 7 characteristics of life

how does a virus make copies of itself

the virus first attaches itself to a host cell then injects its DNa into the cell. the virus uses the cells biomolecules to attach its DNA to make copies

what does HIV do

attachs wbc in the body’s immune system

body becomes vulnerable to infections

results in AIDS

what does AIDS stand for

acquired immune deficiancy syndrom

how is HIV transmitted

sexual intercourse

blood transfusion

mother to foetus through placenta

dirty needles

mother to baby through breast milk

what is the process of classifying organisms called

taxonomy

what is a species

a group of similar organisms that cn interbredd to give fertile offspring

what is the order of taxa

domain

kingdon

phylum

class

order

family

genus

species

what are the three domains of life

1. eubacteria

2. archaea

3. eukaryotes

what are the values of classification

1. helps in conservation of species

2. prevents confusion

3. helps understand the evolutionary relationships between organisms

4. makes it possible to predict characteristics of animals that belong in the same group

how is the binomial system (latin names) ordered

genus name, then species

what are the methods of classification

morphology-based

biochemistry

how is morphology based classification used

group animals accorning to characteristics like:

• morphological- what the body looks like, structure

• anatomical- the study of the body structure/bone structure

when does morphology based classification work

when organisms share characteristics because they evolved from common ancestors

when does morphology based classification fail

when organisms share characteristics because of adaptation and way of life

how does biochemistry classification work

group organisms according to common ancestors

requires the help of genetics

how do you determine common ancestry

DNA analysis

protien analysis

what is evolution

any change in the heritable traits within a population across generations

what are inherited traits

passed from parent to child

transferrred through DNA

physical appearance

what are acquired traits

passed from one person to another

transferred through learning and observing

personality/ behaviour

what was charles darwins theory of evolution

by natural selection

characteristics of populations are changing over time by traits must be heritable

jean baptiste lamarcks theory of evolution

acquired characteristics throughout the life time of an organism

what is required for natural selection to occur

advantageous characteristics

genetic variation