11BIO term 2 exam - cell & cell processes, classification, cell division & genetics

what is an organelle?

A tiny cell structure that carries out a specific function within the cell

what is a tissue?

group of cells with similar structure and function that are made of cells

what is an organ?

A group of different tissues that work together to perform a certain function.

what is an organ system?

group of organs that work together to perform a specific function

what is microscopy?

Unit is micrometers (μm)
1mm\=1000μm

how do you calculate image size?

actual size x magnification

how do you calculate the actual size?

image size/magnification

how do you calculate magnification?

Image size/actual size

what is diffusion?

The movement of particles from an area of high concentration to an area of low concentration, down the concentration gradient until the concentration is equal

what is diffusion in cells?

- cell membranes plays a critical role in regulating movement of dissolved molecules in, and out of cells
- cell membrane is partially permeable so it acts as a barrier for most substances

what factors affect diffusion?

- difference in concentration (concentration gradient)
-\> steeper gradient\=faster diffusion
- temperature -\> higher temperature\=faster the rate of reaction (gains more kinetic energy)
- surface area -\> larger the area\=greater the rate of reaction
- distance -\> shorter distance molecules have to diffuse across\=faster diffusion

what is osmosis?

diffusion of water from a high water potential (dilute) to a low water potential (concentrated) through a partially permeable membrane

how does osmosis work in cells?

cells regulate how much water comes, in and out to maintain their shape

what is an isotonic solution?

- Solute concentration is the same as that inside the cell; no net water movement across the partially permeable membrane
- solution has same water potential

what is a hypotonic solution?

- Solute concentration is less than that inside the cell; cell gains water
- solution has higher water potential (very dilute solution)

what is a hypertonic solution?

- Solute concentration is greater than that inside the cell; cell loses water
- Solution has lower water potential (very concentrated solution)

what happens to a plant cell in a hypertonic solution?

- becomes plasmolysed
- shrivels, and dies
- cell membrane peels away from cell wall

what happens to an animal cell in a hypertonic solution?

- becomes crenated
- shrivels, and dies

what happens to a plant cell in an isotonic solution?

- becomes flaccid

what happens to a animal cell in an isotonic solution?

- is normal

what happens to a plant cell in a hypotonic solution?

- becomes turgid

what happens to an animal cell in a hypotonic solution?

- becomes lysed (hemolysis)

what is turgor pressure?

- the water pressure inside the vacuole of the plant cell in response to the force of water within the cell
- this allows for cells to maintain their shape

what is active transport?

- the movement of ions or molecules across a cell membrane into a region of higher concentration
- assisted by enzymes and requiring energy (usually from respiration)

what does the 'M' in MRS GREN mean?

Movement - an action by an organism/part of organism causing a change in position or place

what does the 'R' in MRS GREN mean?

Respiration - the chemical reaction in cells that breakdown nutrient molecules and release energy for metabolism

what does the 'S' in MRS GREN mean?

Sensitivity - the ability to detect/sense stimuli in the internal/external environment & make appropriate responses

what does the 'G' in MRS GREN mean?

Growth - permanent increase in size and dry mass by an increase in cell number, cell size, or both

what does the 'R' in MRS GREN mean?

Reproduction - the ability to make new organisms of the the same species of themselves

what does the 'E' in MRS GREN mean?

Excretion - the removal from organisms of the waste production of metabolism, toxic material, and substances of excess requirement

what does the 'N' in MRS GREN mean?

Nutrition - the intake of materials for energy, growth, and development
-\> plants need light, carbon dioxide, water, and ions
-\> animals need organic compounds, ions, and water

what is a species?

A group of similar organisms that can breed and produce fertile offspring.

what is classification?

putting things into groups based off of their similarities, and differences

why is classification useful?

- makes it easier to study them
- helps us understand the relationships between the organisms

how are living things classified?

1) morphology - shape, size, structure
2) anatomy - determined through dissection
3) DNA - similarities, and differences in DNA sequence

why is DNA useful for classification?

- can easily compare 2 different species
-\> the more similar the DNA is, the more closely related the species are to one another

what is the order for the Linnaean classification system?

Kingdom -\> Phylum -\> Class -\> Order -\> Family -\> Genus -\> Species
- King Philip Cried Out For Good Soup

what are the 5 kingdoms of life?

1) Animals
2) Plants
3) Fungi
4) Protoctista
5) Prokaryotes

what are the characteristics of animals?

- eukaryotic
- multicellular
- has nucleus
- no cell wall or chloroplasts
- heterotrophic

what are the characteristics of plants?

- eukaryotic
- multicellular
- has cell wall (made of cellulose)
- has nucleus
- autotrophic (photosynthesis)

what are the characteristics of fungi?

- eukaryotic
- multicellular
- have nuclei
- have cell wall (not made of cellulose)
- feed by saprophytic or parasitic nutrition

what are the characteristics of protoctista?

- eukaryotic
- unicellular
- has nucleus
- some have animal/plant-like characteristics

what are the characteristics of prokaryotes?

- prokaryotic
- unicellular
- no nucleus
- no mitochondria
- cell wall (not made of cellulose)

what does ectothermic mean?

cold blood

what does endothermic mean?

warm blooded

what does phylum vertebrates mean?

animals with a supporting rod running along the length of their bodies

what are the characteristics of class fish?

- vertebrates
- scaly skin
- gills
- fins
- eggs in soft eggs
- ectothermic

what are the characteristics of class amphibians?

- vertebrates
- moist, scale-less skin
- larva have gills, adults ahve lungs
- lay eggs in water
- ectothermic

what are the characteristics of class reptiles?

- vertebrates
- scaly skin
- lay waterproof, rubbery eggs
- ahve lungs
- ectothermic

what are the characteristics of class birds?

- vertebrates
- feathers
- wings
- beak
- 4 heart chamber
- lay eggs in hard shells
- endothermic

what are the characteristics of class mammal?

- vertebrates
- hair
- diaphragm
- 4 heart chamber
- different type of teeth (inscissors, canines, premolars, molars)
- young feed off of milk (mammary glands)
- endothermic

what does phylym arthropods mean?

- animals with jointed legs, and no backbone
- waterproof extoskeleton

what are the characteristics of insects?

- 2 pairs of wings
- breathe through tracheae
- body divided by head, thorax, and abdomen
- 3 pairs of jointed legs

what are the characteristics of crustaceans?

- more than 4 pairs of legs
- breathe through gills

what are the characteristics of arachnids?

- 4 pairs of jointed legs
- breathe through gills (book lungs)

what are the characteristics of myriapods?

- body consists of many segments
- each segment has jointed legs
- breathes through tracheae

what are the characteristics of ferns?

- have roots, stems, and leaves
- does not produce flowers
- have leaves called fronds
-\> reproduces by spores which are produced from the underside of fronds

what are the characteristics of flowering plants (angiosperms)?

- have roots, stems, and leaves
- reproduces sexually (flowers, and seeds)
-\> seeds are produced in the ovary of a plant

how are angiosperms classified?

monocotyledons (monocots), or dicotyledons (dicots)

what are the characteristics of monocots?

- single cotyledon (embryonic leaf)
- long narrow leaves with parallel veins
- vascular bundles are scattered
- petals in multiples of 3

what are the characteristics of dicots?

- 2 cotyledons (embryonic leaf)
- broad leaf with network of branching veins
- ring of vascular bundles
- petals in mainly groups of 4, sometimes 5

what is DNA?

- deoxyribonucleic acid
- unit of genetic inheritance that is found as chromosomes in the nucleus
- each chromosome contains a number of genes -\> contains code for a specific protein

what is the structure of DNA?

- double stranded helix
- polynucleotides
-\> linked together by sugar-phosphate base arranged in specific order
- order determines genetic characteristics

what is DNA coding?

- sequence of DNA bases provides a code which determines the types of protein made by cells
- 3 base pairs (triplet) codes for 1 amino acid

what is the DNA ladder?

- each strand of DNA binds to the other using the complementary base-pairing rule
- A (Adenine) binds to T (Thymine)
- G (Guanine) binds to C (Cytosine)
-\> these are joined together by hydrogen bonds

what is an allele?

an alternative version of a gene

what is a mutation?

- change in DNA sequence
- base is substituted for another
- base is deleted or added
- mistake in DNA replication (spontaneous mutations)
- result of exposure to mutagen (induced mutations)

what are diploid cells?

- cells with two sets of chromosomes (2n)
- produced by mitosis
- normal body cells
-\> skin, muscles, liver

what are haploid cells?

- cells with one set of chromosomes (n)
- produced by meiosis
- are gametes (egg, and sperm cells)

what is mitosis?

- nuclear reproduction in body cells that produces two identical daughter cells that are genetically identical to the other, and to the parent cells

what is the process of mitosis?

- DNA replication occurs before mitosis
- the chromosomes in the parent cell are copied
- the chromatids (copied chromosomes) are held together at a point called the centromere

parent cell -\> (interphase) chromosomes are replicated -\> (mitosis occurs) splits into two daughter cells

what is the purpose of mitosis?

- growth
- repair
- asexual reproduction

what is meiosis?

parent cell, DNA duplicates -\> homologous pair up -\> cross over -\> creates variation

-\> first division: 1 chromosome from each homologous pair goes to each daughter cells
second division: each chromatid from each chromosome goes to each daughter cell

-cell reduction division, the chromosome number is halved
- diploid -\> haploid
- results in genetically different daughter cells
- produces gametes

how does meiosis create variation?

- forms new combinations (of paternal, and maternal) chromosomes every time gamete is produced
- gametes randomly fuse at fertilisation -\> each off-spring will be different

what is the process of fertilisation?

haploid gamete combines with another haploid gamete ( fertilsation)-\> produces diploid zygotes -\> goes through mitotis -\> somatic diploid body cells are created -\> diploid organism produce haploid gametes (meisosis)

what is a genotype?

genetic makeup of an organism, in terms of the alleles present

what is a phenotype?

physical characteristics determined by an organism's genotype

what are dominant alleles?

- expressed as capital letter
- always expressed (even if there is only 1 copy)

what are recessive alleles?

- expressed as lower case letter
- only expressed if there are 2 copies of that allele

what does homozygous dominant mean?

- 2 dominant alleles that are identical for the same characteristic (BB)

what does homozygous recessive mean?

- 2 recessive alleles that are identical for the same characteristic (bb)

what does heterozygous mean?

- 2 alleles are both different for the same characteristic (Bb)

what does co dominance mean?

- both traits from a gene are equally expressed in organism
- the allele is not completely recessive, nor dominant

what is a test cross?

- breeding experiment used to determine the genotype of an individual with a dominant phenotype

what is the process of test cross?

individual with dominant phenotype is crossed with individual that is homozygous recessive

if individual with dominant phenotype is homozygous dominant -\> all off-spring will display dominant phenotype (pure-breed)

if individual with dominant phenotype is heterozygous -\> aprpox. half the off-spring will display dominant phenotype, other half will display recessive phenotype (not pure-breed)

what is sex determination?

- last pair of chromosomes are responsible
- XX\=female
- XY\=male

what are sex-linked characteristics?

- Sex-linked characteristics are often associated with the X chromosome as it is larger, and contains more genes

what are X-linked recessive traits?

- more common in males because they only have 1 X chromosome
- if male inherits X-linked recessive allele, he will express that trait as it has no second X chromosome to mask it

- females need to inherit the recessive allele on both X chromosomes to exhibit trait

what are X-linked dominant traits?

- seen in both genders but more severe in males
- if male inherits X-linked dominant allele, he will express that trait as it has no second X chromosome to mask it

- females can become carries, don't exhibit the phenotype but carries the genotype

what is the process of asexual reproduction?

parent cells are divided (mitosis) -\> new cells are genetically identical -\> clones are produced
- only 1 organism needed

what is the result of asexual reproduction?

- does not create diversity
- faster, and efficient for population growth

what is the process of sexual reproduction?

parent cells are divided (meiosis) -\> gametes are created -\> 2 different gametes fuse at fertilisation -\> new combination of genes are created
- 2 organisms fo different sexes needed

what is the result of sexual reproduction?

- creates variation -\> ..enhances adaption to different/changing environments
- survival and potential for evolutionary adaptations increases
- requires more energy, and time

what is self-pollination?

- type of sexual reproduction
- only 1 organism needed
- does not create variation
- quick, does not require outside help

pollen reaches female part of flower -\> plant fertilises own flower

what is variation?

- differences between individuals in a species

what are the causes of variation?

- genotype -\> mutation from change in DNA sequence
- environment -\> temperature, availability to resources. exposure to pollutants -\> affect growth of organism
- natural selection
- artificial selection

what is discontinuous variation?

- individuals within a population can be grouped together into distinct categories
- represented by bar graph

what is continuous variation?

- characteristics in population can vary without distinct categories
- represented by line graph

what are adaptive features?

- inherited characteristics of organisms that have evolved though natural selection to increase its fitness

what is natural selection?

- natural process that occurs in the ecosystem
- certain characteristics make an organism better suited to survive in their environment -\> more likely to reproduce -\> passes on advantageous alleles to off-spring
- less helpful traits become more uncommon

- over times process leads to evolution -\> organism become better adapted to their environment